# Smoking in pregnancy: report

Chapter 2.3 of ZIP Code Destiny, by Vishal Singh (NYU Stern). Generated from the chapter's data files; the reading version is at https://vishalsingh.org/zipcode/smoking-in-pregnancy. Table n of this report is figure n of the chapter.

## Identification

- Title: Smoking in pregnancy
- Label: Before the first breath
- Chapter: 2.3 (Part II, Birth; An American life)
- Question: How does smoking during pregnancy vary with county income within each state, and is the slope the same everywhere?
- Dek: In large counties with a usable count, the share of births to mothers who reported smoking fell from 5.4% in 2018 to 1.9% in 2024 and stayed higher where county income was lower.
- Grain: counties
- Status: published
- Published: 2026-10-09
- Updated: not revised
- Data sources:
  - CDC WONDER natality. CDC WONDER natality, county by tobacco use during pregnancy and county totals, births in 2018 to 2024 (consolidated pulls); 2024 is final; years: 2018-2024; weights: none (full counts of births); shares pooled over counties, births-weighted or unweighted as stated
  - County Health Rankings. County Health Rankings 2024 release, median household income (Census Small Area Income and Poverty Estimates, 2022); years: 2024 release; weights: none (published county values)
  - Area Deprivation Index. Neighborhood Atlas Area Deprivation Index 2023 (v4.0.1), tract national rank, averaged to counties with 2019-2023 tract population; used as a check on the income measure; years: 2023 release (version 4.0.1; built on ACS 2019-2023); weights: 2019-2023 tract population
  - Published estimates from cited studies. Findings of two studies of state policy and maternal smoking: the abstract of Lien and Evans (2005) and Table 2 of Markowitz and coauthors (2017); years: as reported in each study; weights: not applicable
- Canonical URL: https://vishalsingh.org/zipcode/smoking-in-pregnancy
- Report: https://vishalsingh.org/zipcode/smoking-in-pregnancy/report
- Markdown: https://vishalsingh.org/zipcode/smoking-in-pregnancy/report.md
- BibTeX key: singh2026smokinginpregnancy

```bibtex
@misc{singh2026smokinginpregnancy,
  author = {Singh, Vishal},
  title = {Smoking in pregnancy},
  year = {2026},
  url = {https://vishalsingh.org/zipcode/smoking-in-pregnancy},
  note = {In ZIP Code Destiny. Published 9 October 2026.}
}
```

## Principal estimates

The facts the dek and the opening prose cite, in order of appearance.

| Estimand | Population | Period | Value | Interval | n | Weights | Source | Fact id |
| --- | --- | --- | ---: | --- | ---: | --- | --- | --- |
| pooled share of births to mothers who reported smoking; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | 2018 | 5.4% | 95% CI 4.9% to 5.9% | 530 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | share_all_2018 |
| pooled share of births to mothers who reported smoking; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | 2024 | 1.9% | 95% CI 1.7% to 2.1% | 530 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | share_all_2024 |
| count of complete counties | named counties outside California with a published smoking count in every year | births in 2018 to 2024 | 530 |   |   | none (full count) | CDC WONDER natality | n_complete |
| fall in the pooled share from 2018 to 2024; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | 2018 to 2024 | 64.6% | 95% CI 63.5% to 65.7% | 530 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | decline_all |
| difference of two pooled shares; shared bootstrap draws over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; lowest-income third minus highest-income third of counties | 2018 | 4.6 | 95% CI 3.6 to 5.6 | 530 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | gap_2018 |
| state fixed-effects slope of the smoking share (percent) on log2 county income, weighted by births with a known tobacco answer; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope within states | births in 2018 to 2024 | 3.9 | 95% CI 2.7 to 5.5 | 45 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | slope_within_w |
| state fixed-effects slope of the smoking share (percent) on log2 county income, each county counts once; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope within states | births in 2018 to 2024 | 6.6 | 95% CI 5.1 to 8.2 | 45 states | none (each county counts once); interval from a bootstrap over states | CDC WONDER natality | slope_within_u |
| population size at which WONDER natality names a county (a definition) | the counties and cells of CDC WONDER natality | all years (a definition) | 100,000 |   |   | none (definition) | CDC WONDER natality | wonder_threshold |
| count of counties | counties that WONDER natality names in every year from 2018 to 2024 and that have births | births in 2018 to 2024 | 578 |   |   | none (full count) | CDC WONDER natality | n_named |
| share of births in the named counties | live births in the 50 states and DC | births in 2018 to 2024 | 79.5% |   | 578 counties | none (full count) | CDC WONDER natality | named_share |
| share of births in the complete counties | live births in the 50 states and DC | births in 2018 to 2024 | 66.9% |   | 530 counties | none (full count) | CDC WONDER natality | complete_share |

## Findings

Among births in the 530 large counties that CDC WONDER names and that publish a smoking count in every year, the share to mothers who reported smoking fell from 5.4% (95% CI 4.9% to 5.9%) in 2018 to 1.9% (95% CI 1.7% to 2.1%) in 2024. That is a fall of 64.6% (95% CI 63.5% to 65.7%) of the 2018 share. The share was higher in counties with lower median household income in every year, and in 2018 the lowest-income third of counties exceeded the highest-income third by 4.6 (95% CI 3.6 to 5.6) points. Across counties within a state, each doubling of county median household income goes with a smoking share 3.9 (95% CI 2.7 to 5.5) points lower when counties are weighted by their births, for births pooled over 2018 to 2024. When each county counts once it goes with a share 6.6 (95% CI 5.1 to 8.2) points lower.

WONDER names a county only if it has 100,000 residents or more, and every county number in this chapter describes a county of that size. The 578 counties named in every year hold 79.5% of the births in the United States from 2018 to 2024, and the 530 counties used here hold 66.9%. California, which does not collect the item routinely, is left out. Requiring a published smoking count in every year selects on the outcome and leaves out affluent counties, as the next section shows. The smaller counties are pooled by WONDER and cannot be placed on an income scale. Everything below describes counties and groups of births, not mothers. Smoking among adults is the subject of Chapter 7.1, Health behaviors and the supply of care (https://vishalsingh.org/zipcode/health-behaviors-and-the-supply-of-care) for neighborhoods and of Chapter 7.2, Health behaviors, person by person (https://vishalsingh.org/zipcode/health-behaviors-person-by-person) for people. The weight of the babies born to these mothers is the subject of Chapter 2.1, Birthweight and preterm birth (https://vishalsingh.org/zipcode/birthweight-and-preterm-birth).

### What the tobacco item counts

The birth certificate records whether the mother used tobacco during pregnancy, and WONDER reports the answer as Yes, No, Unknown or Not Stated, or Not Reported. This chapter writes smoking for a Yes answer, although the item is named tobacco use and the documentation that comes with the data does not say which products count. A county's smoking share is its Yes births over its births with a known answer, Yes plus No, so births with an Unknown or Not Stated answer are left out of the denominator. The Unknown cells that WONDER publishes hold 0.4% of births. WONDER withholds 1,794 of the 3,710 Unknown cells because each holds fewer than 10 births, so together they could hold at most 0.1%, the most that the left-out births could add.

Not Reported, the code for reporting areas that did not collect the item, is a published zero in all 4,046 county-years. The counties used record 17.1 million births with a known answer from 2018 to 2024, and 632,733 of them are to mothers who reported smoking.

California is left out. WONDER's documentation says that every reporting area except California routinely collects the item. The California counties report a share of 1.2% for 2018, against 5.4% in the counties kept, and below the share in every state kept. The item in California therefore cannot be compared with the item elsewhere, and the 35 California counties are in no estimate.

The smoking count is withheld whenever a county has fewer than 10 smoking births in a year, which happens in low-smoking counties. A withheld cell is missing, never zero, and nothing here is derived from a county total minus the published cells. The named counties have 68 withheld Yes cells, 33 of them in California. The other 35 sit in 13 counties, and those counties are left out of every estimate. Pooling a county over only the years in which its count is published would drop its lowest years and raise its share. A county therefore stays only if its count is published in every year from 2018 to 2024.

The withheld cells could hold at most 315 births, or 0.05% of the smoking births in the counties kept, so they change who is in the sample and not the totals. Virginia lost 4 of its 15 large counties (Arlington, Fairfax, Loudoun and Alexandria), and 9 more counties in Florida, Georgia, Illinois, New York, Tennessee and Texas are out.

The rule selects on the outcome, and the counties it removes are affluent. Of the 13 counties, 11 are above the cut for the highest-income third of the counties kept, and their median income is $109,358 against $72,077 for the counties kept. Suppose each of the 29 withheld cells in the high-income counties held one fewer birth than the withholding floor, a limit and not a value for any cell. Those cells could then add at most 0.17% to the smoking births of the highest-income third.

Adding back the 9 counties whose 2018 count is published moves the weighted within-state slope for 2018 from 4.9 to 4.8 points lower. The same check for 2024 adds only 1 county, because most of the counties left out have a withheld 2024 cell, so it says little about the later years.

### Smoking fell in every income group

Ranking the 530 counties on median household income and splitting them into equal thirds gives three groups, with the lowest-income third up to $64,868 and the middle third up to $80,017. The smoking share in the lowest-income third went from 8.2% (95% CI 7.3% to 9.2%) in 2018 to 3.3% (95% CI 2.9% to 3.7%) in 2024. In the middle third it went from 5.5% (95% CI 4.4% to 6.7%) to 1.9% (95% CI 1.5% to 2.3%). In the highest-income third it went from 3.6% (95% CI 3.2% to 4.0%) to 1.1% (95% CI 1.0% to 1.3%) (Table 1). All of the lines fall in every year and the thirds keep their order, with separate intervals in each year.

Table 1. Smoking in pregnancy fell from 8.2% to 3.3% of births in the lowest-income third of large counties and from 3.6% to 1.1% in the highest-income third

Smoking fell faster in proportion where income is higher. The lowest-income third lost 60.0% (95% CI 57.7% to 62.3%) of its 2018 share and the highest-income third lost 68.8% (95% CI 67.0% to 70.4%), and the two intervals do not overlap.

The gap in points between the lowest-income and highest-income thirds narrowed from 4.6 (95% CI 3.6 to 5.6) to 2.1 (95% CI 1.7 to 2.6), a narrowing of 2.4 (95% CI 1.8 to 3.1) points. The ratio of their shares rose from 2.3 (95% CI 1.9 to 2.7) to 2.9 (95% CI 2.4 to 3.5), a rise of 0.6 (95% CI 0.4 to 0.9). A gap in points shrinks when the level falls even if the proportional difference stays the same. Here the proportional difference grew, so the gradient flattened in one scale and steepened in the other, a pattern that a later section follows year by year.

### Where smoking in pregnancy is most common

Pooled over 2018 to 2024, the share of births to mothers who reported smoking runs from 0.8% in the county at the 5th percentile to 13.2% at the 95th (Table 2). The counties in the top tenth by share are concentrated in Pennsylvania, Ohio, Michigan, New York, Indiana and Missouri. The counties in the bottom tenth are concentrated in Texas, New Jersey, New York, Florida and Georgia, and New York has counties in both groups.

Table 2. The share of births to mothers who smoked is 0.8% in the county at the 5th percentile and 13.2% at the 95th percentile of large counties, and the highest shares cluster in Pennsylvania, Ohio, Michigan, New York, Indiana and Missouri

A county's shade is its own count, so a county with few smoking births has a less stable shade than a large one, and the tooltip gives its interval. The gray counties are not a random draw of counties. Of the 2,613 gray counties, 2,563 are below WONDER's size threshold. The California counties are gray for the reason above, and the counties with a withheld smoking count are gray because their smoking births fell below the withholding floor in some year.

### Smoking is lower where county income is higher

Median household income places each county on one scale. This chapter takes it from County Health Rankings, which reports a Census estimate for 2022, so its year differs from the births, which are from 2018 to 2024. The lowest-income tenth of counties has a median income of $54,059 and the highest-income tenth $107,649, a ratio of 2.0. The smoking share is 5.7% (95% CI 4.2% to 8.0%) in the lowest-income tenth and 1.7% (95% CI 1.4% to 2.1%) in the highest, and the intervals do not overlap (Table 3). The decline is not smooth from tenth to tenth, and counties at lower incomes differ more from one another than counties at higher incomes.

Table 3. Large counties with higher median household income have a lower share of births to mothers who smoked, from 5.7% in the lowest-income tenth to 1.7% in the highest

A second measure checks the choice of income. The Area Deprivation Index orders neighborhoods by deprivation, and a county's rank here is the average of its tracts' ranks, weighted by tract population.[1] The check is not independent, since income is among the index's inputs. Within a state, the smoking share is higher by 1.3 (95% CI 0.9 to 1.6) points for each ten-point step in a county's rank. The correlation between a county's rank and the log of its median income is −0.79 (95% CI −0.90 to −0.67), so the two measures place counties alike. That is agreement and not independent confirmation, and the chapter uses income.

### The slope within states is close to the slope across all counties

A slope across all counties can come from comparing states that differ in both income and smoking. Table 4 separates the two. The first slope is a least-squares line through all counties. The second gives each state its own intercept, a fixed-effects slope that compares counties only inside a state, and the third compares state averages. The slopes are in points of the smoking share for a doubling of county median household income.

Table 4. Within a state, a doubling of county income goes with a smoking share 3.9 points lower when counties are weighted by births, and 6.6 points lower when each county counts once

When counties are weighted by their births with a known answer, the slope across all counties is 4.1 (95% CI 2.7 to 5.9) points, the slope within states 3.9 (95% CI 2.7 to 5.5) and the slope between states 4.7 (95% CI 1.8 to 8.3). The within-state slope differs from the slope across the counties of the same 45 states, those with two or more counties, by +0.3 (95% CI −0.7 to 1.1) points, an interval that includes zero.

When each county counts once, the three are 6.2 (95% CI 4.6 to 8.0), 6.6 (95% CI 5.1 to 8.2) and 5.3 (95% CI 2.2 to 8.7). The within-state slope then differs from that comparison slope by −0.4 (95% CI −1.3 to 0.5) points, again an interval that includes zero. The between-state slope is the least precise because it rests on 49 state averages. The gap between higher-income and lower-income counties therefore appears inside states about as it appears across them.

The weights matter. The weighted within-state slope is shallower than the unweighted one by 2.8 (95% CI 1.3 to 3.9) points. The counties at or above the median in births hold 82.2% of the births. Among them the within-state slope is 3.7 (95% CI 2.6 to 5.1) points, against 8.3 (95% CI 6.3 to 10.2) among the counties below the median, a difference of 4.6 (95% CI 2.5 to 6.6) points. A weighted slope leans on large counties, where the gradient is shallower in points.

Expressed as the proportional difference in the smoking share for a 10% higher county income, the smoking share is 12.0% (95% CI 8.2% to 17.0%) lower within a state when counties are weighted and 16.7% (95% CI 14.4% to 19.0%) lower when each county counts once. The scope figure shows both weightings, the figure of state slopes has a view for each, and the other state figures are weighted by births.

### One slope for each state with enough counties

A state gets a slope of its own if it has at least 8 complete counties. That leaves 26 states and 449 counties, and the other states have too few large counties to fit a line (Table 5). Across these states the common within-state slope is 3.8 (95% CI 2.6 to 5.6) points per doubling.

Every state's estimated slope is below zero, 26 of 26. The interval lies wholly below zero in 10 of them (Colorado, Georgia, Illinois, Indiana, Massachusetts, Missouri, North Carolina, Ohio, Oregon and Virginia), and no interval lies wholly above zero (0 states). With each county counting once, the estimated slope is below zero in 26 states and the interval lies wholly below zero in 12. No interval lies wholly above zero (0 states), as the second view of the figure shows.

Table 5. In all 26 states with a slope of their own the estimated slope is below zero, and the 95% interval lies below zero in 10 when counties are weighted by births

The intervals are wide because a state's line rests on a handful of counties that span less than a doubling of income. The median state's highest-income county has 0.9 doublings more income than its lowest-income county, so a slope per doubling extends past what most states' own counties cover. The figure orders its rows by the estimate only to make it readable, and the order is not a ranking. A state's dot moves with the counties it happens to hold, the intervals overlap widely, and a state is said to differ from another only where the intervals separate. Virginia has 4 of its 15 large counties left out for a withheld count. Those counties are among the highest in income of all the large counties, so its slope describes the counties that remain.

### Whether the slope is the same everywhere

Whether the within-state slope is the same in every state depends on the weights and on the scale. Each of the 26 states with enough large counties for a slope of its own has an estimated slope below zero. The intervals are wide, though, and only 10 lie wholly below zero when counties are weighted by births. Only one of four tests of equal slopes rejects, the test in points when each county counts once (p = 0.009). It does not reject in points when counties are weighted by births (p = 0.108) or in proportion to a state's own smoking share (p = 0.664 weighted and 0.343 unweighted).

A visual impression of spread in a figure of intervals does not test equality, so the chapter tests it. The test compares the spread of the state slopes with the spread their own intervals allow, which is Cochran's Q. With a handful of counties per state the usual reference distribution for Q rejects too often. Each p-value here is therefore the share of bootstrap draws in which Q is at least as large as the observed one, with the draws generated on the assumption that every state has the same slope. The test is run in points and in proportion, with counties weighted by births and with each county counting once.

In points the answer depends on the weights. With each county counting once, p = 0.009 and the estimated standard deviation of the true state slopes is 3.0 (95% CI 1.6 to 3.6) points, with 70% of the variation in the slopes beyond what sampling allows. With counties weighted by births, p = 0.108 and the standard deviation is 1.9 (95% CI 0.0 to 2.7) points, an interval that reaches zero, with 52% of the variation beyond sampling. The standard deviation is the DerSimonian and Laird estimate used in meta-analysis.[2]

The steeper slopes also belong to states with more smoking. Across the states, the correlation between a state's pooled smoking share and its slope is −0.62 (95% CI −0.83 to −0.20), weighted by births (Table 6).

Table 6. States with a higher share of births to mothers who smoked have steeper slopes in points, a correlation of −0.62, with no detectable relation in proportion, where the correlation is −0.19

The same proportional gradient gives a larger difference in points in a state with more smoking, so a steeper slope in points is expected there even if the slope in proportion is the same. The second view of the figure tests that. Written as the proportional difference in the smoking share for a 10% higher county income, the smoking share is 11.9% (95% CI 8.0% to 17.5%) lower. The tests of equal slopes give p = 0.664 weighted and 0.343 unweighted. The correlation with the state's smoking level is −0.19 (95% CI −0.56 to 0.37), an interval that includes zero.

Of the 26 estimated slopes, 25 are below zero in proportion and 8 have an interval wholly below zero. With each county counting once the counts are 26 and 12.

The spread of the true proportional slopes is estimated at 2.1% (95% CI 0.0% to 6.5%) weighted and 2.7% (95% CI 0.0% to 7.0%) unweighted, in the units of the proportional slope. The data are therefore compatible with state slopes that differ moderately around the common value and do not show that they do. The proportional tests have little power: the upper limit of the interval for the unweighted spread sits beside a within-state slope of 16.7% lower. A rejection in points with no rejection in proportion does not show that the scales differ in heterogeneity.

### How the minimum number of counties changes the results

The floor of 8 counties is a choice. A lower floor adds states with a few counties, whose lines are unstable, and a higher floor drops states (Table 7). Moving the floor from 3 to 10 counties changes the number of states from 41 to 23. The number of states with an interval wholly below zero stays between 9 and 11, and at no floor does an interval lie wholly above zero (0 states).

Table 7. Raising the minimum number of counties from 3 to 10 leaves 9 to 11 states with an interval below zero and none above it, and the test of equal proportional slopes never rejects

The tests depend on the weights more than on the floor. In proportion the smallest p-value across all floors and both weightings is 0.319. In points, with counties weighted by births, p runs from 0.108 to 0.165. With each county counting once p is at most 0.009 at every floor above 3 counties. It is 0.264 at a floor of 3 counties, where the lines of the smallest states add noise. The conclusion that the state slopes differ in points rests on counting each county once.

### The slope in points shrank and the slope in proportion grew

The within-state slope can be measured year by year for the same counties (Table 8). In 2018 a doubling of county income went with a smoking share 4.9 (95% CI 3.5 to 7.0) points lower, and in 2024 with a share 2.4 (95% CI 1.7 to 3.4) points lower, so the slope became shallower by 2.5 (95% CI 1.7 to 3.7) points.

In proportion the slope went the other way. A 10% higher county income went with a smoking share 10.1% (95% CI 6.3% to 15.1%) lower in 2018 and 14.7% (95% CI 11.6% to 19.3%) lower in 2024, a steepening of 4.5 (95% CI 3.3 to 5.8) points.

Table 8. The within-state slope in points shrank from 4.9 to 2.4 points per doubling of county income from 2018 to 2024 while the slope in proportion grew from 10.1% to 14.7%

### What moves smoking in pregnancy

Two studies of state policy, each reported under its own design, bear on what changes smoking in pregnancy. Neither measures the county gradient in this chapter.

> Causal evidence: Cigarette taxes and smoking in pregnancy (Matched comparison states around large tax increases, with an instrumental variable for birth weight)
>
> Lien and Evans studied 4 states that adopted large cigarette tax increases and chose control groups of states by a statistical matching procedure. Smoking participation among pregnant women fell in the states with the increases relative to their matched controls.[3] The paper also uses the tax increases as an instrument for smoking in equations for birth weight, pooled across the experiments, and estimates that smoking in pregnancy raises the chance of a low-birthweight birth to 2 times its level without smoking. These statements come from the paper's abstract. The study estimates the effect of higher cigarette taxes on smoking and does not speak to why smoking differs between higher-income and lower-income counties.

> Causal evidence: State income support and maternal smoking (Difference-in-differences)
>
> Markowitz and colleagues compared births in states with and without state Earned Income Tax Credit laws from 1995 to 2013, in a multi-state, multi-year difference-in-differences analysis with state and year-by-quarter fixed effects, standard errors clustered by state and a credit measured in the year before conception.[4] For tobacco use during pregnancy, a low state credit with no refund went with a probability of smoking 1.6 points lower, a high credit with no refund with a probability 0.9 points higher that is significant only at the weakest of the usual levels, and credits with a refund with no significant change. The authors find little difference in maternal health behaviors associated with the credits and write that the policies do not appear to reduce smoking. They find small improvements in birth weight and gestation in states with credits. The estimates are for mothers with a high-school education or less and for the laws in force from 1995 to 2013.

### What these data cannot show

The comparison is between counties. A county with higher median household income has a lower smoking share, and that says nothing about the income of the mothers who smoked, which these data do not hold. The pattern is ecological and need not hold for the mothers inside the counties. The county tables staged for this book carry one stratifier each, so mother's education cannot be crossed with the tobacco item.

The item is reported at birth. The fall in the share from 5.4% to 1.9% can reflect less smoking, a change in how or whether the item is recorded, or a change in who gives birth, and these data cannot separate them. The item is named tobacco use and may include products other than cigarettes.

The counties are the 530 large counties that remain after the rules above, and they hold 66.9% of the births in the United States. California is out because its item is not collected routinely, and 13 counties are out because their smoking count is withheld in some year, a rule that selects on the outcome. Smaller counties are not in these data, so the chapter says nothing about them. The income measure is an estimate for 2022 and the births are from 2018 to 2024, so a county's income stands in for its income in earlier years. The Area Deprivation Index describes neighborhoods in 2019 to 2023.

State slopes rest on 8 counties or more, and the states with a slope hold 449 counties in all. The intervals use a t distribution and standard errors that allow for unequal variance, and they can be too narrow where one county dominates the line. The tests have little power to detect moderate differences, their p-values depend on how counties are weighted, and a test that finds no difference does not show equality. A slope per doubling of income is a statement about a difference larger than most states' own counties span. None of this identifies why smoking is less common where incomes are higher, and the studies in the box above are the only evidence here on what changes it.

## Tables

### Table 1. Smoking in pregnancy fell from 8.2% to 3.3% of births in the lowest-income third of large counties and from 3.6% to 1.1% in the highest-income third

Share of births to mothers who reported smoking, among births with a known tobacco answer, by third of the 530 large counties ranked on median household income, 2018 to 2024, with 95% intervals from a bootstrap over counties

| conf_high | conf_low | n | series | share | year |
| ---: | ---: | ---: | --- | ---: | ---: |
| 9.17 | 7.31 | 603,928 | Lowest-income third | 8.18 | 2018 |
| 8.45 | 6.75 | 599,484 | Lowest-income third | 7.56 | 2019 |
| 7.99 | 6.34 | 580,344 | Lowest-income third | 7.14 | 2020 |
| 6.75 | 5.32 | 579,539 | Lowest-income third | 6.01 | 2021 |
| 5.43 | 4.26 | 579,736 | Lowest-income third | 4.81 | 2022 |
| 4.49 | 3.51 | 567,037 | Lowest-income third | 3.97 | 2023 |
| 3.71 | 2.89 | 567,610 | Lowest-income third | 3.27 | 2024 |
| 6.73 | 4.42 | 938,985 | Middle third | 5.47 | 2018 |
| 6.17 | 4.04 | 924,476 | Middle third | 5 | 2019 |
| 5.63 | 3.70 | 890,673 | Middle third | 4.58 | 2020 |
| 4.59 | 2.99 | 899,921 | Middle third | 3.72 | 2021 |
| 3.66 | 2.37 | 906,572 | Middle third | 2.96 | 2022 |
| 2.91 | 1.89 | 890,288 | Middle third | 2.36 | 2023 |
| 2.32 | 1.52 | 894,429 | Middle third | 1.89 | 2024 |
| 4.04 | 3.22 | 968,024 | Highest-income third | 3.61 | 2018 |
| 3.60 | 2.85 | 959,133 | Highest-income third | 3.21 | 2019 |
| 3.23 | 2.56 | 932,668 | Highest-income third | 2.88 | 2020 |
| 2.58 | 2.05 | 960,611 | Highest-income third | 2.30 | 2021 |
| 1.98 | 1.57 | 962,137 | Highest-income third | 1.76 | 2022 |
| 1.65 | 1.29 | 946,374 | Highest-income third | 1.46 | 2023 |
| 1.28 | 0.990 | 961,896 | Highest-income third | 1.13 | 2024 |
| 5.91 | 4.88 | 2,510,937 | All large counties | 5.40 | 2018 |
| 5.41 | 4.45 | 2,483,093 | All large counties | 4.93 | 2019 |
| 5 | 4.09 | 2,403,685 | All large counties | 4.54 | 2020 |
| 4.08 | 3.34 | 2,440,071 | All large counties | 3.71 | 2021 |
| 3.23 | 2.63 | 2,448,445 | All large counties | 2.93 | 2022 |
| 2.64 | 2.14 | 2,403,699 | All large counties | 2.38 | 2023 |
| 2.11 | 1.72 | 2,423,935 | All large counties | 1.91 | 2024 |

Note: Large counties are the counties that CDC WONDER names individually: those with 100,000 residents or more. WONDER pools the births of every smaller county in a state into one row, so smaller counties are not in these data. Of the 578 large counties named in every year from 2018 to 2024, California (35) and 13 counties with a withheld smoking count are left out, which leaves 530.

Note: A county's smoking share is the births to mothers who reported smoking over the births with a known answer, Yes plus No. Births with an Unknown or Not Stated answer are left out of the denominator.

Note: County median household income is the County Health Rankings 2024 release, a Census Small Area Income and Poverty Estimates value for 2022. Its year differs from the births, which are from 2018 to 2024. Thirds hold equal numbers of counties.

Note: Intervals are 95% intervals from a bootstrap over counties (replicates and seed in the methods note). Births are full counts, so an interval shows how much a pooled share depends on which counties are in the group.

Source: CDC WONDER natality, tobacco use during pregnancy, births in 2018-2024; full counts of births; counties ranked on County Health Rankings 2024 median household income (Census SAIPE 2022); intervals from a bootstrap over counties

Data: https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/smoking_by_income_third.json

### Table 2. The share of births to mothers who smoked is 0.8% in the county at the 5th percentile and 13.2% at the 95th percentile of large counties, and the highest shares cluster in Pennsylvania, Ohio, Michigan, New York, Indiana and Missouri

Share of births to mothers who reported smoking among births with a known tobacco answer, 2018 to 2024, 530 large counties (counties of 100,000 residents or more)

No inline rows: the values of Table 2 are in https://vishalsingh.org/zipcode/data/smoking-in-pregnancy/smoking_county_map.json.

Note: Large counties are the counties that CDC WONDER names individually: those with 100,000 residents or more. WONDER pools the births of every smaller county in a state into one row, so smaller counties are not in these data. Of the 578 large counties named in every year from 2018 to 2024, California (35) and 13 counties with a withheld smoking count are left out, which leaves 530.

Note: A county's smoking share is the births to mothers who reported smoking over the births with a known answer, Yes plus No. Births with an Unknown or Not Stated answer are left out of the denominator.

Note: A county's interval is a Wilson score interval on its births, which treats births as independent; it describes the county's own count and not the spread across counties.

Note: Connecticut is shown as its eight legacy counties, the coding of the source. Alaska is drawn. Puerto Rico is not in these data and is not drawn.

Note: California's counties are gray because the source states that California does not routinely collect the item; its reported share for 2018 is 1.2%, against 5.4% in the counties kept, and lower than the share in any state kept.

Source: CDC WONDER natality, tobacco use during pregnancy, births in 2018-2024; full counts of births; county shares are not weighted

Data: https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/smoking_county_map.json

### Table 3. Large counties with higher median household income have a lower share of births to mothers who smoked, from 5.7% in the lowest-income tenth to 1.7% in the highest

Share of births to mothers who reported smoking, 2018 to 2024, against county median household income (SAIPE 2022, log scale), one dot per county, with pooled shares for tenths of counties

| births | county | income | share |
| ---: | --- | ---: | ---: |
| 17160 | Baldwin County, AL | 71704 | 5.15 |
| 9085 | Calhoun County, AL | 52772 | 11.61 |
| 8291 | Etowah County, AL | 55487 | 9.20 |
| 9150 | Houston County, AL | 56842 | 7.64 |
| 56274 | Jefferson County, AL | 61996 | 2.81 |
| 13383 | Lee County, AL | 59637 | 2.79 |
| 30871 | Madison County, AL | 80426 | 4.14 |
| 36143 | Mobile County, AL | 54315 | 5.40 |
| 20991 | Montgomery County, AL | 56862 | 3.02 |
| 10183 | Morgan County, AL | 62260 | 9.38 |
| 16052 | Shelby County, AL | 98263 | 2.70 |
| 17613 | Tuscaloosa County, AL | 60875 | 3.37 |
| 25397 | Anchorage Borough, AK | 99162 | 5.15 |
| 8855 | Cochise County, AZ | 55254 | 6.15 |
| 9343 | Coconino County, AZ | 64016 | 2.24 |
| 354234 | Maricopa County, AZ | 83668 | 2.41 |
| 12222 | Mohave County, AZ | 54842 | 10.94 |
| 8894 | Navajo County, AZ | 49948 | 5.73 |
| 70533 | Pima County, AZ | 64007 | 4.14 |
| 34615 | Pinal County, AZ | 76232 | 4.17 |
| 12334 | Yavapai County, AZ | 64187 | 8.72 |
| 20395 | Yuma County, AZ | 54209 | 1.73 |
| 26446 | Benton County, AR | 86374 | 4.39 |
| 10357 | Faulkner County, AR | 63429 | 7.01 |
| 34300 | Pulaski County, AR | 57057 | 4.08 |
| 9524 | Saline County, AR | 70330 | 6.72 |
| 11184 | Sebastian County, AR | 52679 | 13.26 |
| 22486 | Washington County, AR | 62100 | 4.57 |
| 43713 | Adams County, CO | 89849 | 3.90 |
| 52605 | Arapahoe County, CO | 93525 | 3.38 |
| 17177 | Boulder County, CO | 96584 | 3.05 |
| 63854 | Denver County, CO | 87619 | 2.94 |
| 25857 | Douglas County, CO | 140768 | 1.44 |
| 63657 | El Paso County, CO | 82248 | 2.95 |
| 38524 | Jefferson County, CO | 102413 | 3.57 |
| 21451 | Larimer County, CO | 88338 | 4.69 |
| 10630 | Mesa County, CO | 69578 | 7.97 |
| 11938 | Pueblo County, CO | 58314 | 8.55 |
| 32098 | Weld County, CO | 90770 | 5.16 |
| 69264 | Fairfield County, CT | 100703 | 0.800 |
| 62361 | Hartford County, CT | 79958 | 2.61 |
| 9943 | Litchfield County, CT | 84689 | 5 |
| 9096 | Middlesex County, CT | 94735 | 2.86 |
| 59057 | New Haven County, CT | 75094 | 3.15 |
| 17367 | New London County, CT | 78552 | 4.35 |
| 8040 | Tolland County, CT | 86430 | 3.40 |
| 7251 | Windham County, CT | 71581 | 7.06 |
| 14677 | Kent County, DE | 71866 | 7.02 |
| 42417 | New Castle County, DE | 85427 | 4.37 |
| 16347 | Sussex County, DE | 81188 | 7.18 |
| 58922 | District of Columbia, DC | 99897 | 1.59 |
| 18307 | Alachua County, FL | 58783 | 3.30 |
| 14566 | Bay County, FL | 65521 | 4.82 |
| 36399 | Brevard County, FL | 74899 | 5.84 |
| 145116 | Broward County, FL | 70834 | 0.440 |
| 7347 | Charlotte County, FL | 65040 | 7.51 |
| 7206 | Citrus County, FL | 52534 | 12.14 |
| 15562 | Clay County, FL | 84364 | 5.49 |
| 88927 | Duval County, FL | 70203 | 3.97 |
| 26002 | Escambia County, FL | 61634 | 7.33 |
| 11396 | Hernando County, FL | 60582 | 6.90 |
| 118938 | Hillsborough County, FL | 74091 | 2.68 |
| 8688 | Indian River County, FL | 69462 | 4.52 |
| 24964 | Lake County, FL | 67637 | 3.71 |
| 50754 | Lee County, FL | 71607 | 2.27 |
| 19699 | Leon County, FL | 61560 | 2.56 |
| 25681 | Manatee County, FL | 72176 | 3.82 |
| 25082 | Marion County, FL | 54517 | 6.04 |
| 8810 | Martin County, FL | 80678 | 2.95 |
| 203848 | Miami-Dade County, FL | 66952 | 0.330 |
| 18394 | Okaloosa County, FL | 76663 | 6.73 |
| 113897 | Orange County, FL | 72129 | 0.960 |
| 32984 | Osceola County, FL | 63782 | 0.880 |
| 103462 | Palm Beach County, FL | 76713 | 0.900 |
| 37949 | Pasco County, FL | 65933 | 6.02 |
| 52244 | Pinellas County, FL | 66427 | 5.59 |
| 60104 | Polk County, FL | 61941 | 3.99 |
| 16550 | St. Johns County, FL | 103757 | 2.76 |
| 23841 | St. Lucie County, FL | 64038 | 3.04 |
| 13753 | Santa Rosa County, FL | 82537 | 7.42 |
| 20203 | Sarasota County, FL | 78309 | 3.20 |
| 31335 | Seminole County, FL | 80296 | 1.63 |
| 34159 | Volusia County, FL | 64601 | 5.03 |
| 9290 | Bartow County, GA | 80017 | 5.87 |
| 14374 | Bibb County, GA | 48539 | 5.57 |
| 11113 | Carroll County, GA | 69924 | 6.63 |
| 25199 | Chatham County, GA | 64029 | 2.04 |
| 19635 | Cherokee County, GA | 99932 | 1.95 |
| 9263 | Clarke County, GA | 49832 | 3.57 |
| 24517 | Clayton County, GA | 57625 | 1.51 |
| 61734 | Cobb County, GA | 96798 | 0.640 |
| 11456 | Columbia County, GA | 94224 | 1.55 |
| 11488 | Coweta County, GA | 87618 | 2.15 |
| 70132 | DeKalb County, GA | 76736 | 0.550 |
| 11749 | Douglas County, GA | 79242 | 2.55 |
| 86437 | Fulton County, GA | 89798 | 0.810 |
| 76767 | Gwinnett County, GA | 83918 | 0.530 |
| 18680 | Hall County, GA | 76789 | 2.17 |
| 19450 | Henry County, GA | 82379 | 1.84 |
| 13798 | Houston County, GA | 71237 | 3.26 |
| 11235 | Lowndes County, GA | 52623 | 3.90 |
| 18898 | Muscogee County, GA | 53740 | 3.33 |
| 12678 | Paulding County, GA | 87459 | 2.07 |
| 18963 | Richmond County, GA | 50079 | 3.09 |
| 8845 | Whitfield County, GA | 61680 | 8.64 |
| 13721 | Hawaii County, HI | 71143 | 5.29 |
| 78177 | Honolulu County, HI | 96304 | 0.980 |
| 11460 | Maui County, HI | 89794 | 2.34 |
| 35094 | Ada County, ID | 87748 | 3.21 |
| 12619 | Bonneville County, ID | 74505 | 5.42 |
| 22754 | Canyon County, ID | 70594 | 5.05 |
| 13213 | Kootenai County, ID | 75583 | 5.87 |
| 14447 | Champaign County, IL | 61205 | 4.98 |
| 383990 | Cook County, IL | 76614 | 1.23 |
| 7336 | DeKalb County, IL | 71882 | 4.57 |
| 68155 | DuPage County, IL | 102383 | 0.910 |
| 40030 | Kane County, IL | 93475 | 1.52 |
| 8124 | Kankakee County, IL | 70494 | 8.03 |
| 47165 | Lake County, IL | 101621 | 1.47 |
| 7651 | LaSalle County, IL | 64711 | 11.93 |
| 21307 | McHenry County, IL | 99128 | 2.45 |
| 11768 | McLean County, IL | 71825 | 6.26 |
| 8211 | Macon County, IL | 60648 | 11.53 |
| 18669 | Madison County, IL | 67441 | 8.96 |
| 15369 | Peoria County, IL | 65421 | 9.19 |
| 11015 | Rock Island County, IL | 62652 | 7.46 |
| 19069 | St. Clair County, IL | 67185 | 8.16 |
| 14427 | Sangamon County, IL | 73684 | 11.01 |
| 9039 | Tazewell County, IL | 73285 | 9.55 |
| 48876 | Will County, IL | 97076 | 2.09 |
| 23007 | Winnebago County, IL | 62557 | 9.35 |
| 36434 | Allen County, IN | 65967 | 6.36 |
| 10024 | Clark County, IN | 68493 | 8.82 |
| 7485 | Delaware County, IN | 54059 | 14.83 |
| 20565 | Elkhart County, IN | 63777 | 6.54 |
| 26730 | Hamilton County, IN | 117068 | 1.08 |
| 12470 | Hendricks County, IN | 94760 | 3.70 |
| 13190 | Johnson County, IN | 83036 | 7.22 |
| 37599 | Lake County, IN | 66169 | 4.72 |
| 7988 | La Porte County, IN | 66336 | 14.20 |
| 9959 | Madison County, IN | 58926 | 14.33 |
| 98302 | Marion County, IN | 62776 | 5.89 |
| 7574 | Monroe County, IN | 64299 | 9.69 |
| 11244 | Porter County, IN | 84352 | 5.55 |
| 22894 | St. Joseph County, IN | 61028 | 6.36 |
| 13904 | Tippecanoe County, IN | 56088 | 7.40 |
| 14931 | Vanderburgh County, IN | 57997 | 9.65 |
| 7850 | Vigo County, IN | 52286 | 14.76 |
| 11181 | Black Hawk County, IA | 62020 | 10.06 |
| 11741 | Johnson County, IA | 74909 | 2.67 |
| 18297 | Linn County, IA | 74134 | 7.81 |
| 45236 | Polk County, IA | 77369 | 6.53 |
| 13715 | Scott County, IA | 68576 | 8.09 |
| 9940 | Woodbury County, IA | 66830 | 11.03 |
| 7172 | Douglas County, KS | 67482 | 7.11 |
| 48396 | Johnson County, KS | 99174 | 1.51 |
| 46079 | Sedgwick County, KS | 64720 | 7.31 |
| 13791 | Shawnee County, KS | 61255 | 11 |
| 16991 | Wyandotte County, KS | 58701 | 4.74 |
| 11860 | Boone County, KY | 90265 | 7.10 |
| 26174 | Fayette County, KY | 63667 | 7.25 |
| 9385 | Hardin County, KY | 61920 | 12.66 |
| 66206 | Jefferson County, KY | 64719 | 7.48 |
| 15267 | Kenton County, KY | 77284 | 11.12 |
| 12523 | Warren County, KY | 60651 | 5.40 |
| 11564 | Ascension Parish, LA | 81284 | 1.79 |
| 11284 | Bossier Parish, LA | 63812 | 4.33 |
| 19927 | Caddo Parish, LA | 47699 | 5.03 |
| 17588 | Calcasieu Parish, LA | 61797 | 3.29 |
| 38804 | East Baton Rouge Parish, LA | 61376 | 1.83 |
| 37142 | Jefferson Parish, LA | 61157 | 1.77 |
| 23015 | Lafayette Parish, LA | 58641 | 2.65 |
| 12889 | Livingston Parish, LA | 72887 | 3.41 |
| 29212 | Orleans Parish, LA | 51913 | 1.57 |
| 13883 | Ouachita Parish, LA | 47283 | 5.01 |
| 11340 | Rapides Parish, LA | 55870 | 5.91 |
| 20165 | St. Tammany Parish, LA | 78629 | 4.81 |
| 13379 | Tangipahoa Parish, LA | 54942 | 2.92 |
| 9366 | Terrebonne Parish, LA | 57376 | 4.49 |
| 8063 | Androscoggin County, ME | 62848 | 10.62 |
| 19382 | Cumberland County, ME | 88571 | 4.16 |
| 7569 | Kennebec County, ME | 63191 | 10.13 |
| 8985 | Penobscot County, ME | 60761 | 10.92 |
| 12761 | York County, ME | 81315 | 7.14 |
| 47232 | Anne Arundel County, MD | 112525 | 2.98 |
| 65127 | Baltimore County, MD | 86198 | 3.64 |
| 11842 | Carroll County, MD | 105096 | 4.52 |
| 7980 | Cecil County, MD | 84513 | 12.29 |
| 12626 | Charles County, MD | 112932 | 3.08 |
| 21532 | Frederick County, MD | 116796 | 3.27 |
| 18269 | Harford County, MD | 100334 | 5.16 |
| 22263 | Howard County, MD | 133068 | 1.07 |
| 81230 | Montgomery County, MD | 118020 | 0.680 |
| 77654 | Prince George's County, MD | 93833 | 0.930 |
| 9508 | St. Mary's County, MD | 112154 | 5.57 |
| 11317 | Washington County, MD | 69271 | 11.33 |
| 50682 | Baltimore city, MD | 54735 | 5.46 |
| 10378 | Barnstable County, MA | 89774 | 5.69 |
| 6394 | Berkshire County, MA | 71102 | 10.76 |
| 39208 | Bristol County, MA | 80702 | 5.39 |
| 59374 | Essex County, MA | 92118 | 1.94 |
| 33261 | Hampden County, MA | 64030 | 4.36 |
| 6421 | Hampshire County, MA | 81878 | 4.06 |
| 112463 | Middlesex County, MA | 118494 | 1.49 |
| 49207 | Norfolk County, MA | 115770 | 1.39 |
| 36705 | Plymouth County, MA | 102647 | 3.06 |
| 59159 | Suffolk County, MA | 84548 | 1.12 |
| 59265 | Worcester County, MA | 86078 | 4.64 |
| 8704 | Allegan County, MI | 75893 | 8.95 |
| 6344 | Bay County, MI | 56388 | 15.61 |
| 10619 | Berrien County, MI | 61790 | 10.17 |
| 10267 | Calhoun County, MI | 59652 | 13.60 |
| 7231 | Eaton County, MI | 71499 | 8.39 |
| 30202 | Genesee County, MI | 57443 | 13.24 |
| 20064 | Ingham County, MI | 60571 | 9.30 |
| 11293 | Jackson County, MI | 61299 | 14.49 |
| 19251 | Kalamazoo County, MI | 69689 | 11.28 |
| 56939 | Kent County, MI | 76923 | 2.97 |
| 11820 | Livingston County, MI | 101227 | 4.42 |
| 61113 | Macomb County, MI | 73927 | 5.40 |
| 10327 | Monroe County, MI | 72166 | 10.08 |
| 13230 | Muskegon County, MI | 58303 | 12.49 |
| 87631 | Oakland County, MI | 90801 | 2.97 |
| 21658 | Ottawa County, MI | 85968 | 3.42 |
| 13662 | Saginaw County, MI | 54064 | 12.71 |
| 10247 | St. Clair County, MI | 64894 | 14.59 |
| 22242 | Washtenaw County, MI | 80941 | 4.21 |
| 147992 | Wayne County, MI | 55928 | 5.38 |
| 28534 | Anoka County, MN | 92249 | 4.04 |
| 34738 | Dakota County, MN | 97727 | 2.62 |
| 103273 | Hennepin County, MN | 89418 | 2.57 |
| 13730 | Olmsted County, MN | 88032 | 4.29 |
| 47518 | Ramsey County, MN | 75041 | 3.96 |
| 12496 | St. Louis County, MN | 63141 | 12.86 |
| 11743 | Scott County, MN | 115687 | 2.73 |
| 14058 | Stearns County, MN | 72378 | 6.62 |
| 19167 | Washington County, MN | 107649 | 2.69 |
| 12703 | Wright County, MN | 95259 | 4.09 |
| 15318 | DeSoto County, MS | 79967 | 4.69 |
| 17326 | Harrison County, MS | 55916 | 6.20 |
| 19281 | Hinds County, MS | 47479 | 4.05 |
| 10864 | Jackson County, MS | 61515 | 7.29 |
| 12150 | Rankin County, MS | 72906 | 4.06 |
| 13590 | Boone County, MO | 63981 | 7.45 |
| 20781 | Clay County, MO | 78930 | 6.28 |
| 7934 | Franklin County, MO | 65779 | 13.12 |
| 22914 | Greene County, MO | 55751 | 11.69 |
| 60264 | Jackson County, MO | 62509 | 7.23 |
| 10728 | Jasper County, MO | 53548 | 11.36 |
| 16677 | Jefferson County, MO | 78297 | 11.52 |
| 28851 | St. Charles County, MO | 98925 | 4.23 |
| 72521 | St. Louis County, MO | 79609 | 4.59 |
| 24881 | St. Louis city, MO | 52278 | 7.78 |
| 7491 | Missoula County, MT | 68210 | 7.74 |
| 12828 | Yellowstone County, MT | 78216 | 13.21 |
| 55993 | Douglas County, NE | 74424 | 4.89 |
| 26001 | Lancaster County, NE | 68358 | 5.90 |
| 16778 | Sarpy County, NE | 98619 | 3.64 |
| 175327 | Clark County, NV | 70838 | 2.53 |
| 34800 | Washoe County, NV | 80245 | 3.30 |
| 28953 | Hillsborough County, NH | 96415 | 5.46 |
| 8961 | Merrimack County, NH | 84898 | 5.99 |
| 18894 | Rockingham County, NH | 107445 | 2.88 |
| 7901 | Strafford County, NH | 82845 | 8.10 |
| 19276 | Atlantic County, NJ | 76108 | 6.15 |
| 61993 | Bergen County, NJ | 113885 | 0.640 |
| 31600 | Burlington County, NJ | 100188 | 3.37 |
| 42040 | Camden County, NJ | 81372 | 4.21 |
| 12773 | Cumberland County, NJ | 60892 | 6.73 |
| 69450 | Essex County, NJ | 74747 | 1.39 |
| 20188 | Gloucester County, NJ | 97851 | 4.81 |
| 65455 | Hudson County, NJ | 82361 | 0.770 |
| 7241 | Hunterdon County, NJ | 137334 | 1.84 |
| 28477 | Mercer County, NJ | 94832 | 2.14 |
| 59370 | Middlesex County, NJ | 102073 | 1.24 |
| 42622 | Monmouth County, NJ | 117699 | 1.37 |
| 33345 | Morris County, NJ | 131562 | 0.700 |
| 68988 | Ocean County, NJ | 81152 | 1.57 |
| 43760 | Passaic County, NJ | 78779 | 1.30 |
| 22098 | Somerset County, NJ | 134735 | 1.27 |
| 9249 | Sussex County, NJ | 111308 | 3.80 |
| 46241 | Union County, NJ | 96483 | 0.730 |
| 7177 | Warren County, NJ | 97729 | 4.82 |
| 45975 | Bernalillo County, NM | 65034 | 3.68 |
| 17941 | Dona Ana County, NM | 52011 | 2.31 |
| 9258 | Sandoval County, NM | 82862 | 2.59 |
| 9165 | San Juan County, NM | 51898 | 5.72 |
| 7868 | Santa Fe County, NM | 72836 | 3.34 |
| 19642 | Albany County, NY | 76997 | 6.03 |
| 124230 | Bronx County, NY | 45864 | 0.610 |
| 12582 | Broome County, NY | 60533 | 12.14 |
| 8649 | Chautauqua County, NY | 55644 | 12.90 |
| 18274 | Dutchess County, NY | 90740 | 3.05 |
| 65097 | Erie County, NY | 69888 | 6.82 |
| 12213 | Jefferson County, NY | 58763 | 9.42 |
| 243533 | Kings County, NY | 73244 | 0.230 |
| 51812 | Monroe County, NY | 68169 | 5.89 |
| 96131 | Nassau County, NY | 135528 | 0.420 |
| 103761 | New York County, NY | 95514 | 0.340 |
| 13749 | Niagara County, NY | 63565 | 12.44 |
| 16428 | Oneida County, NY | 63894 | 9.73 |
| 33510 | Onondaga County, NY | 70939 | 7.68 |
| 6712 | Ontario County, NY | 76601 | 8.05 |
| 37791 | Orange County, NY | 88532 | 1.83 |
| 8126 | Oswego County, NY | 59335 | 16.21 |
| 175588 | Queens County, NY | 80180 | 0.310 |
| 10754 | Rensselaer County, NY | 80040 | 7.86 |
| 35382 | Richmond County, NY | 91582 | 0.840 |
| 6920 | St. Lawrence County, NY | 59451 | 14.29 |
| 14110 | Saratoga County, NY | 93341 | 5.07 |
| 12440 | Schenectady County, NY | 74206 | 3.62 |
| 108290 | Suffolk County, NY | 119253 | 1.47 |
| 4697 | Tompkins County, NY | 72025 | 8.11 |
| 10433 | Ulster County, NY | 79340 | 6.58 |
| 69003 | Westchester County, NY | 108037 | 0.520 |
| 13463 | Alamance County, NC | 61034 | 5.30 |
| 7779 | Brunswick County, NC | 73536 | 10.09 |
| 16798 | Buncombe County, NC | 67906 | 6.48 |
| 18401 | Cabarrus County, NC | 79649 | 3.74 |
| 11683 | Catawba County, NC | 63934 | 9.60 |
| 9020 | Craven County, NC | 63076 | 6.43 |
| 36657 | Cumberland County, NC | 58013 | 5.94 |
| 12394 | Davidson County, NC | 63590 | 10.56 |
| 28827 | Durham County, NC | 79524 | 1.67 |
| 30890 | Forsyth County, NC | 62992 | 4.78 |
| 18836 | Gaston County, NC | 65430 | 9.20 |
| 41136 | Guilford County, NC | 63822 | 4.19 |
| 13131 | Harnett County, NC | 65242 | 6.06 |
| 7163 | Henderson County, NC | 65252 | 6.91 |
| 13881 | Iredell County, NC | 73446 | 6.37 |
| 18759 | Johnston County, NC | 80612 | 1.88 |
| 104441 | Mecklenburg County, NC | 80645 | 1.24 |
| 15155 | New Hanover County, NC | 70995 | 4.47 |
| 26602 | Onslow County, NC | 62190 | 3.71 |
| 8043 | Orange County, NC | 87780 | 2.90 |
| 14419 | Pitt County, NC | 57319 | 5.62 |
| 10891 | Randolph County, NC | 58037 | 8.76 |
| 12735 | Robeson County, NC | 39931 | 12.40 |
| 11120 | Rowan County, NC | 61105 | 9.38 |
| 17327 | Union County, NC | 95079 | 2.68 |
| 90404 | Wake County, NC | 97099 | 1.31 |
| 11364 | Wayne County, NC | 55635 | 5.10 |
| 16501 | Cass County, ND | 70002 | 5.67 |
| 8560 | Allen County, OH | 60384 | 13.19 |
| 7213 | Ashtabula County, OH | 52468 | 17.37 |
| 30275 | Butler County, OH | 74841 | 9.08 |
| 11086 | Clark County, OH | 57264 | 13.77 |
| 15560 | Clermont County, OH | 79492 | 10.49 |
| 6770 | Columbiana County, OH | 54167 | 19.70 |
| 91896 | Cuyahoga County, OH | 60808 | 5.11 |
| 14885 | Delaware County, OH | 121528 | 3.07 |
| 11746 | Fairfield County, OH | 82447 | 9.12 |
| 123475 | Franklin County, OH | 69762 | 6.16 |
| 11884 | Greene County, OH | 82769 | 7.20 |
| 72529 | Hamilton County, OH | 67033 | 6.84 |
| 14711 | Lake County, OH | 76163 | 7.22 |
| 13273 | Licking County, OH | 76596 | 10.69 |
| 22139 | Lorain County, OH | 67124 | 10.23 |
| 34681 | Lucas County, OH | 57971 | 8.80 |
| 16265 | Mahoning County, OH | 54774 | 17.37 |
| 11543 | Medina County, OH | 89108 | 5.09 |
| 8098 | Miami County, OH | 72887 | 9.95 |
| 43181 | Montgomery County, OH | 62794 | 7.89 |
| 9489 | Portage County, OH | 72965 | 10.39 |
| 9476 | Richland County, OH | 54906 | 14.90 |
| 27672 | Stark County, OH | 64557 | 12 |
| 38632 | Summit County, OH | 66034 | 8.82 |
| 13986 | Trumbull County, OH | 54406 | 18.90 |
| 16762 | Warren County, OH | 104523 | 4.95 |
| 9852 | Wayne County, OH | 70121 | 8.09 |
| 8697 | Wood County, OH | 67254 | 6.17 |
| 13869 | Canadian County, OK | 81761 | 3.17 |
| 19195 | Cleveland County, OK | 70923 | 5.55 |
| 11392 | Comanche County, OK | 55600 | 6.77 |
| 77162 | Oklahoma County, OK | 61580 | 4.16 |
| 61069 | Tulsa County, OK | 63442 | 6.06 |
| 26210 | Clackamas County, OR | 96915 | 3.64 |
| 12969 | Deschutes County, OR | 84281 | 4.83 |
| 6962 | Douglas County, OR | 55837 | 14.02 |
| 14669 | Jackson County, OR | 68239 | 7.53 |
| 21179 | Lane County, OR | 64192 | 7.80 |
| 10064 | Linn County, OR | 67265 | 9.08 |
| 27793 | Marion County, OR | 70861 | 4.88 |
| 52225 | Multnomah County, OR | 79432 | 3.67 |
| 42730 | Washington County, OR | 98706 | 1.64 |
| 6311 | Adams County, PA | 76554 | 7.68 |
| 84377 | Allegheny County, PA | 71973 | 6.21 |
| 10503 | Beaver County, PA | 67135 | 11.60 |
| 31618 | Berks County, PA | 72157 | 5.17 |
| 8107 | Blair County, PA | 57884 | 14.60 |
| 38785 | Bucks County, PA | 105202 | 4.32 |
| 11971 | Butler County, PA | 81507 | 7.97 |
| 8256 | Cambria County, PA | 54612 | 15.42 |
| 7626 | Centre County, PA | 67654 | 5.76 |
| 37871 | Chester County, PA | 117326 | 2.68 |
| 18379 | Cumberland County, PA | 81295 | 5.94 |
| 22887 | Dauphin County, PA | 67813 | 7.02 |
| 43218 | Delaware County, PA | 83856 | 4.01 |
| 18412 | Erie County, PA | 56489 | 12.92 |
| 8259 | Fayette County, PA | 51494 | 19.22 |
| 11879 | Franklin County, PA | 73709 | 8.28 |
| 14059 | Lackawanna County, PA | 61168 | 12.14 |
| 48303 | Lancaster County, PA | 82434 | 4.37 |
| 10896 | Lebanon County, PA | 69490 | 6.65 |
| 27840 | Lehigh County, PA | 72590 | 5.17 |
| 22049 | Luzerne County, PA | 59358 | 10.59 |
| 7855 | Lycoming County, PA | 61729 | 14.41 |
| 7091 | Mercer County, PA | 57702 | 15.13 |
| 9632 | Monroe County, PA | 79824 | 8.13 |
| 58583 | Montgomery County, PA | 106743 | 2.96 |
| 19365 | Northampton County, PA | 75468 | 5.68 |
| 132998 | Philadelphia County, PA | 56385 | 3.77 |
| 8821 | Schuylkill County, PA | 63680 | 15.63 |
| 13560 | Washington County, PA | 70751 | 11.75 |
| 19863 | Westmoreland County, PA | 71152 | 10.76 |
| 33202 | York County, PA | 79938 | 6.98 |
| 10172 | Kent County, RI | 84230 | 4.49 |
| 47909 | Providence County, RI | 74190 | 3 |
| 5881 | Washington County, RI | 99015 | 4.06 |
| 12958 | Aiken County, SC | 67728 | 5.78 |
| 15927 | Anderson County, SC | 62708 | 9.42 |
| 13125 | Beaufort County, SC | 83687 | 2.65 |
| 20728 | Berkeley County, SC | 79259 | 4.68 |
| 34628 | Charleston County, SC | 79969 | 2.09 |
| 13622 | Dorchester County, SC | 74730 | 4.77 |
| 11111 | Florence County, SC | 52650 | 5.86 |
| 44972 | Greenville County, SC | 71833 | 4.05 |
| 22821 | Horry County, SC | 61375 | 8.01 |
| 22711 | Lexington County, SC | 73022 | 3.87 |
| 8508 | Pickens County, SC | 55333 | 8.02 |
| 32196 | Richland County, SC | 61010 | 1.17 |
| 28596 | Spartanburg County, SC | 58535 | 5.81 |
| 9377 | Sumter County, SC | 56937 | 3.55 |
| 20749 | York County, SC | 83692 | 4.07 |
| 19479 | Minnehaha County, SD | 75623 | 5.87 |
| 9955 | Pennington County, SD | 67573 | 10.60 |
| 9054 | Blount County, TN | 69713 | 11.70 |
| 70452 | Davidson County, TN | 72561 | 3.48 |
| 30527 | Hamilton County, TN | 75127 | 5.74 |
| 36932 | Knox County, TN | 70013 | 8.33 |
| 25144 | Montgomery County, TN | 67478 | 6.31 |
| 30515 | Rutherford County, TN | 77320 | 4.44 |
| 86476 | Shelby County, TN | 61452 | 3.14 |
| 10394 | Sullivan County, TN | 54361 | 15.76 |
| 15744 | Sumner County, TN | 87453 | 7.40 |
| 8668 | Washington County, TN | 64270 | 12.01 |
| 12421 | Wilson County, TN | 88462 | 6.09 |
| 42118 | Bell County, TX | 62412 | 2.56 |
| 183122 | Bexar County, TX | 65839 | 0.730 |
| 32604 | Brazoria County, TX | 86197 | 2.06 |
| 18809 | Brazos County, TX | 60355 | 1.64 |
| 85710 | Collin County, TX | 113943 | 0.490 |
| 12761 | Comal County, TX | 92979 | 1.83 |
| 257839 | Dallas County, TX | 70871 | 0.520 |
| 75897 | Denton County, TX | 102711 | 0.790 |
| 20859 | Ector County, TX | 64868 | 3.33 |
| 18034 | Ellis County, TX | 89314 | 1.79 |
| 78428 | El Paso County, TX | 53441 | 0.600 |
| 64701 | Fort Bend County, TX | 105583 | 0.370 |
| 27343 | Galveston County, TX | 75947 | 3.09 |
| 11900 | Grayson County, TX | 66141 | 4.61 |
| 11611 | Gregg County, TX | 60932 | 5.27 |
| 13957 | Guadalupe County, TX | 86043 | 1.58 |
| 454216 | Harris County, TX | 68748 | 0.640 |
| 96678 | Hidalgo County, TX | 48825 | 0.260 |
| 22497 | Jefferson County, TX | 55065 | 4.38 |
| 16371 | Johnson County, TX | 76747 | 4.19 |
| 16578 | Kaufman County, TX | 92814 | 1.74 |
| 28325 | Lubbock County, TX | 59138 | 3.22 |
| 23327 | McLennan County, TX | 63160 | 3.55 |
| 20997 | Midland County, TX | 81187 | 2.76 |
| 56694 | Montgomery County, TX | 95241 | 2.02 |
| 30350 | Nueces County, TX | 60250 | 1.62 |
| 12350 | Parker County, TX | 95277 | 3.38 |
| 11012 | Potter County, TX | 51028 | 8.70 |
| 11715 | Randall County, TX | 77066 | 5.63 |
| 21030 | Smith County, TX | 67978 | 2.18 |
| 191010 | Tarrant County, TX | 76285 | 1.45 |
| 13649 | Taylor County, TX | 61798 | 5.19 |
| 10398 | Tom Green County, TX | 60348 | 3.65 |
| 110483 | Travis County, TX | 95151 | 0.760 |
| 10856 | Wichita County, TX | 56634 | 7.51 |
| 53621 | Williamson County, TX | 101891 | 0.840 |
| 14399 | Cache County, UT | 76631 | 1.11 |
| 33922 | Davis County, UT | 103143 | 1.70 |
| 105389 | Salt Lake County, UT | 91713 | 1.94 |
| 83649 | Utah County, UT | 95085 | 0.770 |
| 15947 | Washington County, UT | 75572 | 1.52 |
| 24434 | Weber County, UT | 83465 | 3.07 |
| 9528 | Chittenden County, VT | 86579 | 5.78 |
| 28141 | Chesterfield County, VA | 100149 | 2.13 |
| 25974 | Henrico County, VA | 82187 | 2.69 |
| 43962 | Prince William County, VA | 119051 | 0.710 |
| 11100 | Spotsylvania County, VA | 96322 | 4.94 |
| 12619 | Stafford County, VA | 134456 | 2.60 |
| 19782 | Chesapeake city, VA | 87127 | 2.85 |
| 11050 | Hampton city, VA | 64086 | 4.24 |
| 17847 | Newport News city, VA | 63350 | 4.93 |
| 22033 | Norfolk city, VA | 60030 | 3.92 |
| 20909 | Richmond city, VA | 58719 | 3.95 |

The first 500 of 530 rows; every row is in https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/smoking_vs_income_counties.json.

Note: Large counties are the counties that CDC WONDER names individually: those with 100,000 residents or more. WONDER pools the births of every smaller county in a state into one row, so smaller counties are not in these data. Of the 578 large counties named in every year from 2018 to 2024, California (35) and 13 counties with a withheld smoking count are left out, which leaves 530.

Note: A county's smoking share is the births to mothers who reported smoking over the births with a known answer, Yes plus No. Births with an Unknown or Not Stated answer are left out of the denominator.

Note: County median household income is the County Health Rankings 2024 release, a Census Small Area Income and Poverty Estimates value for 2022. Its year differs from the births, which are from 2018 to 2024.

Note: Intervals are 95% intervals from a bootstrap over counties (replicates and seed in the methods note). Births are full counts, so an interval shows how much a pooled share depends on which counties are in the group. Tenths hold equal numbers of counties.

Source: CDC WONDER natality, tobacco use during pregnancy, births in 2018-2024; full counts of births; counties ranked on County Health Rankings 2024 median household income (Census SAIPE 2022); tenths pooled by births, intervals from a bootstrap over counties

Data: https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/smoking_vs_income_counties.json

### Table 4. Within a state, a doubling of county income goes with a smoking share 3.9 points lower when counties are weighted by births, and 6.6 points lower when each county counts once

Change in the share of births to mothers who smoked, in percentage points per doubling of county median household income (SAIPE 2022), across all counties, within states and between states, 2018 to 2024, with 95% intervals from a bootstrap over states

| conf_high | conf_low | estimate | n | scope | weighting |
| ---: | ---: | ---: | ---: | --- | --- |
| −2.71 | −5.91 | −4.12 | 49 | Across all counties | Weighted by births |
| −2.75 | −5.53 | −3.88 | 45 | Within states | Weighted by births |
| −1.82 | −8.33 | −4.71 | 49 | Between states | Weighted by births |
| −4.57 | −8 | −6.24 | 49 | Across all counties | Each county counts once |
| −5.11 | −8.20 | −6.63 | 45 | Within states | Each county counts once |
| −2.19 | −8.69 | −5.29 | 49 | Between states | Each county counts once |

Note: Large counties are the counties that CDC WONDER names individually: those with 100,000 residents or more. WONDER pools the births of every smaller county in a state into one row, so smaller counties are not in these data. Of the 578 large counties named in every year from 2018 to 2024, California (35) and 13 counties with a withheld smoking count are left out, which leaves 530.

Note: County median household income is the County Health Rankings 2024 release, a Census Small Area Income and Poverty Estimates value for 2022. Its year differs from the births, which are from 2018 to 2024.

Note: Intervals are 95% intervals from a bootstrap over states (replicates and seed in the methods note), which allows for counties in one state resembling each other. The between-state slope compares 49 state means, so its interval is the widest; 45 states have two or more counties and contribute to the within-state slope.

Note: The weighted slopes weight each county by its births with a known answer. The unweighted slopes count each county once.

Source: CDC WONDER natality, tobacco use during pregnancy, births in 2018-2024; full counts of births; counties ranked on County Health Rankings 2024 median household income (Census SAIPE 2022); slopes weighted by births or unweighted as labeled; intervals from a bootstrap over states

Data: https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/slope_scope.json

### Table 5. In all 26 states with a slope of their own the estimated slope is below zero, and the 95% interval lies below zero in 10 when counties are weighted by births

Change in the share of births to mothers who smoked per doubling of county median household income (SAIPE 2022), one dot per state with at least 8 complete large counties, 2018 to 2024, with 95% intervals; four views by scale and by weighting

| State | Scale | Counties | Slope | Lower limit of the 95% interval | Upper limit of the 95% interval | Complete counties | Counties left out for a withheld count | State share (%) |
| --- | --- | --- | ---: | ---: | ---: | ---: | ---: | ---: |
| Alabama | points | Weighted by births | −3.28 | −7.14 | 0.58 | 12 | 0 | 4.6 |
| Arizona | points | Weighted by births | −4.97 | −13.64 | 3.70 | 9 | 0 | 3.2 |
| Colorado | points | Weighted by births | −4.35 | −8.56 | −0.14 | 11 | 0 | 3.7 |
| Connecticut | points | Weighted by births | −6.42 | −16.92 | 4.08 | 8 | 0 | 2.6 |
| Florida | points | Weighted by births | −3.97 | −10.03 | 2.09 | 32 | 1 | 2.7 |
| Georgia | points | Weighted by births | −3.34 | −4.95 | −1.73 | 22 | 2 | 1.8 |
| Illinois | points | Weighted by births | −8.37 | −16.40 | −0.33 | 19 | 1 | 2.9 |
| Indiana | points | Weighted by births | −7.17 | −10.21 | −4.12 | 17 | 0 | 6.7 |
| Louisiana | points | Weighted by births | −0.81 | −6.94 | 5.31 | 14 | 0 | 3.1 |
| Maryland | points | Weighted by births | −4.04 | −9.51 | 1.43 | 13 | 0 | 3.1 |
| Massachusetts | points | Weighted by births | −4.24 | −7.52 | −0.97 | 11 | 0 | 2.8 |
| Michigan | points | Weighted by births | −7.45 | −24.40 | 9.51 | 20 | 0 | 6.6 |
| Minnesota | points | Weighted by births | −7.80 | −19.54 | 3.93 | 10 | 0 | 3.7 |
| Missouri | points | Weighted by births | −6.23 | −12.12 | −0.34 | 10 | 0 | 7.2 |
| New Jersey | points | Weighted by births | −1.86 | −4.47 | 0.75 | 19 | 0 | 1.9 |
| New York | points | Weighted by births | −2.36 | −9.13 | 4.41 | 27 | 1 | 2.3 |
| North Carolina | points | Weighted by births | −8.20 | −11.15 | −5.25 | 27 | 0 | 4.2 |
| Ohio | points | Weighted by births | −7.34 | −13.71 | −0.98 | 28 | 0 | 8.3 |
| Oregon | points | Weighted by births | −9.98 | −15.26 | −4.70 | 9 | 0 | 4.8 |
| Pennsylvania | points | Weighted by births | −5.10 | −15.68 | 5.47 | 31 | 0 | 6.4 |
| South Carolina | points | Weighted by births | −4.51 | −10.99 | 1.97 | 15 | 0 | 4.5 |
| Tennessee | points | Weighted by births | −0.91 | −28.66 | 26.85 | 11 | 1 | 5.5 |
| Texas | points | Weighted by births | −0.63 | −2.10 | 0.83 | 36 | 3 | 1.3 |
| Virginia | points | Weighted by births | −2.72 | −5.20 | −0.25 | 11 | 4 | 2.8 |
| Washington | points | Weighted by births | −5.69 | −14.20 | 2.83 | 12 | 0 | 3.7 |
| Wisconsin | points | Weighted by births | −3.37 | −20.54 | 13.80 | 15 | 0 | 5.5 |
| Alabama | points | Each county counts once | −5.47 | −11.26 | 0.33 | 12 | 0 | 4.6 |
| Arizona | points | Each county counts once | −4.59 | −13.11 | 3.92 | 9 | 0 | 3.2 |
| Colorado | points | Each county counts once | −5.89 | −9.84 | −1.94 | 11 | 0 | 3.7 |
| Connecticut | points | Each county counts once | −8.16 | −18.13 | 1.81 | 8 | 0 | 2.6 |
| Florida | points | Each county counts once | −4.49 | −10.73 | 1.75 | 32 | 1 | 2.7 |
| Georgia | points | Each county counts once | −2.96 | −4.84 | −1.07 | 22 | 2 | 1.8 |
| Illinois | points | Each county counts once | −11.40 | −14.72 | −8.09 | 19 | 1 | 2.9 |
| Indiana | points | Each county counts once | −9.50 | −13.06 | −5.93 | 17 | 0 | 6.7 |
| Louisiana | points | Each county counts once | −1.54 | −6.01 | 2.93 | 14 | 0 | 3.1 |
| Maryland | points | Each county counts once | −5.80 | −17.26 | 5.67 | 13 | 0 | 3.1 |
| Massachusetts | points | Each county counts once | −6.41 | −14.99 | 2.16 | 11 | 0 | 2.8 |
| Michigan | points | Each county counts once | −12.63 | −18.78 | −6.48 | 20 | 0 | 6.6 |
| Minnesota | points | Each county counts once | −9.52 | −22.26 | 3.22 | 10 | 0 | 3.7 |
| Missouri | points | Each county counts once | −5.82 | −12.76 | 1.12 | 10 | 0 | 7.2 |
| New Jersey | points | Each county counts once | −2.87 | −6.11 | 0.37 | 19 | 0 | 1.9 |
| New York | points | Each county counts once | −8.60 | −16.15 | −1.06 | 27 | 1 | 2.3 |
| North Carolina | points | Each county counts once | −7.86 | −10.18 | −5.54 | 27 | 0 | 4.2 |
| Ohio | points | Each county counts once | −11.15 | −15.57 | −6.73 | 28 | 0 | 8.3 |
| Oregon | points | Each county counts once | −12.13 | −20.36 | −3.90 | 9 | 0 | 4.8 |
| Pennsylvania | points | Each county counts once | −11.72 | −16.34 | −7.11 | 31 | 0 | 6.4 |
| South Carolina | points | Each county counts once | −4.71 | −9.31 | −0.10 | 15 | 0 | 4.5 |
| Tennessee | points | Each county counts once | −9.43 | −29.00 | 10.13 | 11 | 1 | 5.5 |
| Texas | points | Each county counts once | −2.73 | −5.19 | −0.26 | 36 | 3 | 1.3 |
| Virginia | points | Each county counts once | −2.09 | −4.23 | 0.05 | 11 | 4 | 2.8 |
| Washington | points | Each county counts once | −4.69 | −15.06 | 5.67 | 12 | 0 | 3.7 |
| Wisconsin | points | Each county counts once | −6.69 | −15.34 | 1.95 | 15 | 0 | 5.5 |
| Alabama | proportion | Weighted by births | −7.62 | −17.55 | 3.51 | 12 | 0 | 4.6 |
| Arizona | proportion | Weighted by births | −13.80 | −42.48 | 29.20 | 9 | 0 | 3.2 |
| Colorado | proportion | Weighted by births | −14.86 | −24.34 | −4.20 | 11 | 0 | 3.7 |
| Connecticut | proportion | Weighted by births | −37.17 | −76.01 | 64.60 | 8 | 0 | 2.6 |
| Florida | proportion | Weighted by births | −9.96 | −39.70 | 34.45 | 32 | 1 | 2.7 |
| Georgia | proportion | Weighted by births | −20.60 | −27.42 | −13.14 | 22 | 2 | 1.8 |
| Illinois | proportion | Weighted by births | −24.70 | −43.86 | 1.01 | 19 | 1 | 2.9 |
| Indiana | proportion | Weighted by births | −21.06 | −37.44 | −0.40 | 17 | 0 | 6.7 |
| Louisiana | proportion | Weighted by births | −2.35 | −25.39 | 27.80 | 14 | 0 | 3.1 |
| Maryland | proportion | Weighted by births | −17.27 | −33.50 | 2.91 | 13 | 0 | 3.1 |
| Massachusetts | proportion | Weighted by births | −17.13 | −28.02 | −4.60 | 11 | 0 | 2.8 |
| Michigan | proportion | Weighted by births | −15.68 | −37.23 | 13.26 | 20 | 0 | 6.6 |
| Minnesota | proportion | Weighted by births | −18.02 | −32.93 | 0.21 | 10 | 0 | 3.7 |
| Missouri | proportion | Weighted by births | −12.11 | −20.52 | −2.81 | 10 | 0 | 7.2 |
| New Jersey | proportion | Weighted by births | −11.04 | −23.37 | 3.28 | 19 | 0 | 1.9 |
| New York | proportion | Weighted by births | −7.29 | −27.80 | 19.05 | 27 | 1 | 2.3 |
| North Carolina | proportion | Weighted by births | −26.20 | −33.19 | −18.48 | 27 | 0 | 4.2 |
| Ohio | proportion | Weighted by births | −10.74 | −19.29 | −1.28 | 28 | 0 | 8.3 |
| Oregon | proportion | Weighted by births | −25.39 | −40.79 | −5.98 | 9 | 0 | 4.8 |
| Pennsylvania | proportion | Weighted by births | −9.71 | −27.57 | 12.55 | 31 | 0 | 6.4 |
| South Carolina | proportion | Weighted by births | −9.25 | −30.76 | 18.96 | 15 | 0 | 4.5 |
| Tennessee | proportion | Weighted by births | 5.28 | −39.93 | 84.52 | 11 | 1 | 5.5 |
| Texas | proportion | Weighted by births | −0.52 | −15.83 | 17.58 | 36 | 3 | 1.3 |
| Virginia | proportion | Weighted by births | −16.02 | −33.86 | 6.62 | 11 | 4 | 2.8 |
| Washington | proportion | Weighted by births | −21.40 | −49.98 | 23.49 | 12 | 0 | 3.7 |
| Wisconsin | proportion | Weighted by births | −10.92 | −43.04 | 39.32 | 15 | 0 | 5.5 |
| Alabama | proportion | Each county counts once | −12.06 | −21.15 | −1.91 | 12 | 0 | 4.6 |
| Arizona | proportion | Each county counts once | −10.74 | −31.45 | 16.21 | 9 | 0 | 3.2 |
| Colorado | proportion | Each county counts once | −17.41 | −21.63 | −12.96 | 11 | 0 | 3.7 |
| Connecticut | proportion | Each county counts once | −33.42 | −63.91 | 22.83 | 8 | 0 | 2.6 |
| Florida | proportion | Each county counts once | −11.39 | −26.28 | 6.51 | 32 | 1 | 2.7 |
| Georgia | proportion | Each county counts once | −15.69 | −23.22 | −7.43 | 22 | 2 | 1.8 |
| Illinois | proportion | Each county counts once | −31.15 | −37.93 | −23.62 | 19 | 1 | 2.9 |
| Indiana | proportion | Each county counts once | −21.07 | −33.11 | −6.85 | 17 | 0 | 6.7 |
| Louisiana | proportion | Each county counts once | −5.57 | −22.73 | 15.41 | 14 | 0 | 3.1 |
| Maryland | proportion | Each county counts once | −17.22 | −37.28 | 9.25 | 13 | 0 | 3.1 |
| Massachusetts | proportion | Each county counts once | −20.85 | −35.58 | −2.75 | 11 | 0 | 2.8 |
| Michigan | proportion | Each county counts once | −20.74 | −29.38 | −11.04 | 20 | 0 | 6.6 |
| Minnesota | proportion | Each county counts once | −19.90 | −33.80 | −3.08 | 10 | 0 | 3.7 |
| Missouri | proportion | Each county counts once | −10.92 | −21.19 | 0.69 | 10 | 0 | 7.2 |
| New Jersey | proportion | Each county counts once | −12.55 | −24.87 | 1.79 | 19 | 0 | 1.9 |
| New York | proportion | Each county counts once | −24.26 | −42.67 | 0.05 | 27 | 1 | 2.3 |
| North Carolina | proportion | Each county counts once | −20.97 | −28.79 | −12.29 | 27 | 0 | 4.2 |
| Ohio | proportion | Each county counts once | −15.14 | −18.88 | −11.24 | 28 | 0 | 8.3 |
| Oregon | proportion | Each county counts once | −24.96 | −36.84 | −10.85 | 9 | 0 | 4.8 |
| Pennsylvania | proportion | Each county counts once | −17.99 | −23.00 | −12.65 | 31 | 0 | 6.4 |
| South Carolina | proportion | Each county counts once | −11.04 | −23.82 | 3.89 | 15 | 0 | 4.5 |
| Tennessee | proportion | Each county counts once | −10.64 | −36.17 | 25.12 | 11 | 1 | 5.5 |
| Texas | proportion | Each county counts once | −11.50 | −25.12 | 4.60 | 36 | 3 | 1.3 |
| Virginia | proportion | Each county counts once | −11.24 | −25.06 | 5.14 | 11 | 4 | 2.8 |
| Washington | proportion | Each county counts once | −13.76 | −38.91 | 21.75 | 12 | 0 | 3.7 |
| Wisconsin | proportion | Each county counts once | −17.17 | −34.81 | 5.24 | 15 | 0 | 5.5 |

Views: Points, weighted by births (measure = points, weighting = Weighted by births); Points, each county once (measure = points, weighting = Each county counts once); Percent, weighted by births (measure = proportion, weighting = Weighted by births); Percent, each county once (measure = proportion, weighting = Each county counts once).

Note: Large counties are the counties that CDC WONDER names individually: those with 100,000 residents or more. WONDER pools the births of every smaller county in a state into one row, so smaller counties are not in these data. Of the 578 large counties named in every year from 2018 to 2024, California (35) and 13 counties with a withheld smoking count are left out, which leaves 530.

Note: County median household income is the County Health Rankings 2024 release, a Census Small Area Income and Poverty Estimates value for 2022. Its year differs from the births, which are from 2018 to 2024.

Note: A state gets a slope when it has at least 8 complete counties, which gives 26 states and 449 counties. Intervals are 95% intervals from a t distribution with the state's counties minus two degrees of freedom and heteroskedasticity-robust (HC3) standard errors, so a state with few counties has a wide interval and the interval may be too narrow where one county dominates.

Note: Virginia has 4 of its 15 large counties left out for a withheld smoking count, and counties left out in other states are listed in the data table. A state with counties left out rests on the rest.

Note: Counties differ by less than a doubling of income in a typical state: the median span between a state's lowest and highest county income is 0.9 doublings, so the slopes extend beyond what most states' own counties cover.

Source: CDC WONDER natality, tobacco use during pregnancy, births in 2018-2024; full counts of births; counties ranked on County Health Rankings 2024 median household income (Census SAIPE 2022); state slopes weighted by births with a known answer or unweighted as labeled, 95% t intervals

Data: https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/state_slopes.json

### Table 6. States with a higher share of births to mothers who smoked have steeper slopes in points, a correlation of −0.62, with no detectable relation in proportion, where the correlation is −0.19

Slope of the smoking share on county median household income against the state's pooled smoking share, one dot per state with a slope of its own, 2018 to 2024; slopes in percentage points per doubling of income or as a percent difference per 10% higher income

| births | level | measure | slope | state |
| ---: | ---: | --- | ---: | --- |
| 245196 | 4.57 | points | −3.28 | Alabama |
| 531425 | 3.19 | points | −4.97 | Arizona |
| 381504 | 3.68 | points | −4.35 | Colorado |
| 242379 | 2.62 | points | −6.42 | Connecticut |
| 1416167 | 2.71 | points | −3.97 | Florida |
| 565701 | 1.80 | points | −3.34 | Georgia |
| 777655 | 2.90 | points | −8.37 | Illinois |
| 359143 | 6.66 | points | −7.17 | Indiana |
| 269558 | 3.08 | points | −0.810 | Louisiana |
| 437262 | 3.07 | points | −4.04 | Maryland |
| 471835 | 2.79 | points | −4.24 | Massachusetts |
| 580836 | 6.58 | points | −7.45 | Michigan |
| 297960 | 3.72 | points | −7.80 | Minnesota |
| 279141 | 7.17 | points | −6.23 | Missouri |
| 691343 | 1.88 | points | −1.86 | New Jersey |
| 1319857 | 2.30 | points | −2.36 | New York |
| 621319 | 4.22 | points | −8.20 | North Carolina |
| 704336 | 8.32 | points | −7.34 | Ohio |
| 214801 | 4.75 | points | −9.98 | Oregon |
| 802576 | 6.36 | points | −5.10 | Pennsylvania |
| 312029 | 4.49 | points | −4.51 | South Carolina |
| 336327 | 5.53 | points | −0.910 | Tennessee |
| 2167850 | 1.27 | points | −0.630 | Texas |
| 249880 | 2.82 | points | −2.72 | Virginia |
| 491503 | 3.66 | points | −5.69 | Washington |
| 284970 | 5.53 | points | −3.37 | Wisconsin |
| 245196 | 4.57 | proportion | −7.62 | Alabama |
| 531425 | 3.19 | proportion | −13.80 | Arizona |
| 381504 | 3.68 | proportion | −14.86 | Colorado |
| 242379 | 2.62 | proportion | −37.17 | Connecticut |
| 1416167 | 2.71 | proportion | −9.96 | Florida |
| 565701 | 1.80 | proportion | −20.60 | Georgia |
| 777655 | 2.90 | proportion | −24.70 | Illinois |
| 359143 | 6.66 | proportion | −21.06 | Indiana |
| 269558 | 3.08 | proportion | −2.35 | Louisiana |
| 437262 | 3.07 | proportion | −17.27 | Maryland |
| 471835 | 2.79 | proportion | −17.13 | Massachusetts |
| 580836 | 6.58 | proportion | −15.68 | Michigan |
| 297960 | 3.72 | proportion | −18.02 | Minnesota |
| 279141 | 7.17 | proportion | −12.11 | Missouri |
| 691343 | 1.88 | proportion | −11.04 | New Jersey |
| 1319857 | 2.30 | proportion | −7.29 | New York |
| 621319 | 4.22 | proportion | −26.20 | North Carolina |
| 704336 | 8.32 | proportion | −10.74 | Ohio |
| 214801 | 4.75 | proportion | −25.39 | Oregon |
| 802576 | 6.36 | proportion | −9.71 | Pennsylvania |
| 312029 | 4.49 | proportion | −9.25 | South Carolina |
| 336327 | 5.53 | proportion | 5.28 | Tennessee |
| 2167850 | 1.27 | proportion | −0.520 | Texas |
| 249880 | 2.82 | proportion | −16.02 | Virginia |
| 491503 | 3.66 | proportion | −21.40 | Washington |
| 284970 | 5.53 | proportion | −10.92 | Wisconsin |

Views: Percentage points per doubling (measure = points); Percent per 10 percent higher income (measure = proportion).

Note: Large counties are the counties that CDC WONDER names individually: those with 100,000 residents or more. WONDER pools the births of every smaller county in a state into one row, so smaller counties are not in these data. Of the 578 large counties named in every year from 2018 to 2024, California (35) and 13 counties with a withheld smoking count are left out, which leaves 530.

Note: County median household income is the County Health Rankings 2024 release, a Census Small Area Income and Poverty Estimates value for 2022. Its year differs from the births, which are from 2018 to 2024.

Note: Dots are the same 26 states as in the previous figure, with counties weighted by births, and the state slopes carry the wide intervals shown there; the correlation interval allows for the states drawn.

Note: The state's smoking share is the births to mothers who reported smoking over births with a known answer, pooled over its complete counties.

Source: CDC WONDER natality, tobacco use during pregnancy, births in 2018-2024; full counts of births; counties ranked on County Health Rankings 2024 median household income (Census SAIPE 2022); state slopes weighted by births with a known answer; correlations weighted by births, intervals from a bootstrap over states

Data: https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/slope_vs_state_level.json

### Table 7. Raising the minimum number of counties from 3 to 10 leaves 9 to 11 states with an interval below zero and none above it, and the test of equal proportional slopes never rejects

States with a slope of their own, states with an interval below or above zero, and wild-bootstrap p-values for equal slopes in percentage points and in proportion, by the fewest complete counties a state needs, 2018 to 2024

| Fewest complete counties | States | Counties | States with interval below zero | States with interval above zero | p, points, weighted | p, points, each county once | p, proportion, weighted | p, proportion, each county once |
| ---: | ---: | ---: | ---: | ---: | --- | --- | --- | --- |
| 3 | 41 | 518 | 11 | 0 | 0.109 | 0.264 | 0.788 | 0.784 |
| 4 | 37 | 506 | 11 | 0 | 0.121 | 0.006 | 0.790 | 0.710 |
| 5 | 35 | 498 | 11 | 0 | 0.118 | 0.006 | 0.743 | 0.648 |
| 6 | 30 | 473 | 10 | 0 | 0.117 | 0.006 | 0.639 | 0.344 |
| 8 | 26 | 449 | 10 | 0 | 0.108 | 0.009 | 0.664 | 0.343 |
| 10 | 23 | 423 | 9 | 0 | 0.165 | 0.0005 | 0.601 | 0.319 |

Note: A p-value tests that every state in the row has the same slope. It is the share of wild-bootstrap draws (replicates and seed in the methods note) in which Cochran's Q is at least as large as observed, so the smallest value it can take is one over the number of draws plus one.

Note: Large counties are the counties that CDC WONDER names individually: those with 100,000 residents or more. WONDER pools the births of every smaller county in a state into one row, so smaller counties are not in these data. Of the 578 large counties named in every year from 2018 to 2024, California (35) and 13 counties with a withheld smoking count are left out, which leaves 530.

Note: County median household income is the County Health Rankings 2024 release, a Census Small Area Income and Poverty Estimates value for 2022. Its year differs from the births, which are from 2018 to 2024.

Source: CDC WONDER natality, tobacco use during pregnancy, births in 2018-2024; full counts of births; counties ranked on County Health Rankings 2024 median household income (Census SAIPE 2022); state slopes weighted by births or unweighted as labeled; p-values from a wild bootstrap

Data: https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/cutoff_sensitivity.json

### Table 8. The within-state slope in points shrank from 4.9 to 2.4 points per doubling of county income from 2018 to 2024 while the slope in proportion grew from 10.1% to 14.7%

Within-state slope of the smoking share on county median household income (SAIPE 2022), by year of birth, 2018 to 2024, in percentage points per doubling of income or as a percent difference per 10% higher income, with 95% intervals from a bootstrap over states

| conf_high | conf_low | measure | n | slope | year |
| ---: | ---: | --- | ---: | ---: | ---: |
| −3.45 | −6.98 | points | 45 | −4.89 | 2018 |
| −3.31 | −6.71 | points | 45 | −4.70 | 2019 |
| −3.25 | −6.62 | points | 45 | −4.65 | 2020 |
| −2.80 | −5.76 | points | 45 | −4.02 | 2021 |
| −2.32 | −4.78 | points | 45 | −3.31 | 2022 |
| −1.99 | −4.03 | points | 45 | −2.81 | 2023 |
| −1.70 | −3.36 | points | 45 | −2.39 | 2024 |
| −6.33 | −15.12 | proportion | 45 | −10.13 | 2018 |
| −6.88 | −15.88 | proportion | 45 | −10.87 | 2019 |
| −7.56 | −16.68 | proportion | 45 | −11.73 | 2020 |
| −7.69 | −17.47 | proportion | 45 | −12.18 | 2021 |
| −9.10 | −18.22 | proportion | 45 | −12.86 | 2022 |
| −10.07 | −18.86 | proportion | 45 | −13.82 | 2023 |
| −11.61 | −19.29 | proportion | 45 | −14.67 | 2024 |

Views: Percentage points per doubling (measure = points); Percent per 10 percent higher income (measure = proportion).

Note: Large counties are the counties that CDC WONDER names individually: those with 100,000 residents or more. WONDER pools the births of every smaller county in a state into one row, so smaller counties are not in these data. Of the 578 large counties named in every year from 2018 to 2024, California (35) and 13 counties with a withheld smoking count are left out, which leaves 530.

Note: County median household income is the County Health Rankings 2024 release, a Census Small Area Income and Poverty Estimates value for 2022. Its year differs from the births, which are from 2018 to 2024.

Note: Intervals are 95% intervals from a bootstrap over states (replicates and seed in the methods note), which allows for counties in one state resembling each other. The same counties are used in every year, and each is published in every year.

Note: The slopes are negative: a value farther below zero means a lower smoking share for a doubling of county income.

Source: CDC WONDER natality, tobacco use during pregnancy, births in 2018-2024; full counts of births; counties ranked on County Health Rankings 2024 median household income (Census SAIPE 2022); slopes weighted by births with a known answer, intervals from a bootstrap over states

Data: https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/slope_over_time.json

## All estimates

Every fact in facts.json (130), sorted by id.

| Fact id | Value | Unit | Estimand | Population | Period | Interval | n | Weights | Source | Note |
| --- | ---: | --- | --- | --- | --- | --- | ---: | --- | --- | --- |
| above_max | 0 | states | most states with a 95% interval above zero across the cutoffs | states with a slope of their own at any cutoff | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| adi_income_corr | −0.79 | correlation coefficient | births-weighted correlation of log county median household income with the county ADI rank; bootstrap interval over states | the complete counties | income for 2022; ADI built on ACS 2019-2023 | 95% CI −0.90 to −0.67 | 530 counties | births with a known tobacco answer | Area Deprivation Index | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| adi_slope | 1.3 | percentage points per ten-point step in the county Area Deprivation Index national rank | state fixed-effects slope of the smoking share on the county ADI rank, births-weighted; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope within states | births in 2018 to 2024 | 95% CI 0.9 to 1.6 | 45 states | births with a known tobacco answer; interval from a bootstrap over states | Area Deprivation Index | County ADI is the population-weighted mean of tract national ranks (1 least deprived, 100 most deprived) from the 2023 Area Deprivation Index with ACS 2019-2023 tract population; its period differs from the births, which are from 2018 to 2024. |
| below_max | 11 | states | most states with a 95% interval below zero across the cutoffs | states with a slope of their own at any cutoff | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| below_min | 9 | states | fewest states with a 95% interval below zero across the cutoffs | states with a slope of their own at any cutoff | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| big_births_share | 82.2% | percent of births with a known answer | share of births in the larger half of counties by births | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | births in 2018 to 2024 |   | 530 counties | none (full count) | CDC WONDER natality |   |
| big_slope | 3.7 | percentage points per doubling of county median household income | state fixed-effects slope among the larger half of counties by births with a known answer, each county counting once; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; the larger half of counties by births with a known answer | births in 2018 to 2024 | 95% CI 2.6 to 5.1 | 35 states | none (each county counts once); interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| births_known | 17.1 million | live births | count of births with a known tobacco answer (Yes plus No) | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | births in 2018 to 2024 |   | 530 counties | none (full count) | CDC WONDER natality |   |
| births_smoking | 632,733 | live births | count of births with a Yes answer to tobacco use during pregnancy | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | births in 2018 to 2024 |   | 530 counties | none (full count) | CDC WONDER natality |   |
| ca_share_2018 | 1.2% | percent of births with a known answer | pooled share over the published county cells of 2018; withheld cells leave both sums | live births in the California counties with a published Yes cell | 2018 |   |   | none (full count) | CDC WONDER natality |   |
| common_pct | 11.9% | percent difference in the smoking share for a 10 percent higher county median household income | state fixed-effects slope in proportion, births-weighted, over the states with a slope of their own; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; states with a slope of their own | births in 2018 to 2024 | 95% CI 8.0% to 17.5% | 26 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| common_points | 3.8 | percentage points per doubling of county median household income | state fixed-effects slope in points, births-weighted, over the states with a slope of their own; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; states with a slope of their own | births in 2018 to 2024 | 95% CI 2.6 to 5.6 | 26 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| complete_share | 66.9% | percent of live births in the United States | share of births in the complete counties | live births in the 50 states and DC | births in 2018 to 2024 |   | 530 counties | none (full count) | CDC WONDER natality |   |
| corr_level_prop | −0.19 | correlation coefficient | births-weighted correlation across states between the state's pooled smoking share and its slope in proportion; bootstrap interval over states | states with a slope of their own | births in 2018 to 2024 | 95% CI −0.56 to 0.37 | 26 states | births with a known tobacco answer in the state; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| corr_level_pts | −0.62 | correlation coefficient | births-weighted correlation across states between the state's pooled smoking share and its slope in points; bootstrap interval over states | states with a slope of their own | births in 2018 to 2024 | 95% CI −0.83 to −0.20 | 26 states | births with a known tobacco answer in the state; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| counties_k | 449 | counties | count of counties | complete counties in the states with a slope of their own | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| county_p5 | 0.8% | percent of births with a known answer | 5th percentile of the county shares, one county one count | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | births in 2018 to 2024 |   | 530 counties | none (each county counts once) | CDC WONDER natality |   |
| county_p95 | 13.2% | percent of births with a known answer | 95th percentile of the county shares, one county one count | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | births in 2018 to 2024 |   | 530 counties | none (each county counts once) | CDC WONDER natality |   |
| cut_hi | 10 | counties | largest cutoff tried (a choice) | complete counties in a state | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| cut_lo | 3 | counties | smallest cutoff tried (a choice) | complete counties in a state | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| cut_low_mid | $64,868 | dollars | highest county median household income in the lowest-income third of the complete counties | the complete counties | income for 2022 |   | 530 counties | none (county values) | County Health Rankings | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| cut_mid_high | $80,017 | dollars | highest county median household income in the middle third of the complete counties | the complete counties | income for 2022 |   | 530 counties | none (county values) | County Health Rankings | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| dec10_income | $107,649 | dollars | median of the county median household incomes in the tenth | the highest-income tenth of the complete counties | income for 2022 |   | 53 counties | none (county values) | County Health Rankings | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| dec10_share | 1.7% | percent of births with a known answer | pooled share of births to mothers who reported smoking; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; highest-income tenth of counties by median household income | births in 2018 to 2024 | 95% CI 1.4% to 2.1% | 53 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| dec1_income | $54,059 | dollars | median of the county median household incomes in the tenth | the lowest-income tenth of the complete counties | income for 2022 |   | 53 counties | none (county values) | County Health Rankings | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| dec1_share | 5.7% | percent of births with a known answer | pooled share of births to mothers who reported smoking; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; lowest-income tenth of counties by median household income | births in 2018 to 2024 | 95% CI 4.2% to 8.0% | 53 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| dec_income_ratio | 2.0 | ratio of incomes | median county income in the highest-income tenth over the median in the lowest-income tenth | the lowest-income and highest-income tenths of the complete counties | income for 2022 |   | 106 counties | none (county values) | County Health Rankings | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| decline_all | 64.6% | percent of the 2018 share | fall in the pooled share from 2018 to 2024; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | 2018 to 2024 | 95% CI 63.5% to 65.7% | 530 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality |   |
| decline_terc_1 | 60.0% | percent of the 2018 share | fall in the pooled share from 2018 to 2024; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; the lowest-income third of the complete counties by median household income | 2018 to 2024 | 95% CI 57.7% to 62.3% | 176 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| decline_terc_3 | 68.8% | percent of the 2018 share | fall in the pooled share from 2018 to 2024; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; the highest-income third of the complete counties by median household income | 2018 to 2024 | 95% CI 67.0% to 70.4% | 177 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| dropped_high | 11 | counties | count of those counties with a median household income above the cut for the highest-income third of the complete counties | named counties outside California with a withheld smoking count | births in 2018 to 2024 |   | 13 counties | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| dropped_high_cells | 29 | county-year cells | count of withheld cells | withheld Yes cells of the counties left out that are above the cut for the highest-income third | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| dropped_high_max_share | 0.17% | percent of smoking births | largest share of those births that the withheld cells of the high-income counties left out could add, at 9 births each | smoking births in the highest-income third of the complete counties | births in 2018 to 2024 |   | 177 counties | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| dropped_income_median | $109,358 | dollars | median household income of the counties left out for a withheld count | named counties outside California | income for 2022 |   | 13 counties | none (county values) | County Health Rankings | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| dropped_max_births | 315 | live births | largest number of births those cells could hold, at 9 births each | the withheld Yes cells of the counties left out outside California | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| dropped_max_share | 0.05% | percent of smoking births | largest share of the smoking births in the complete counties that the withheld cells could add, at 9 births each | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | births in 2018 to 2024 |   | 530 counties | none (full count) | CDC WONDER natality |   |
| dropped_other_states | 9 | counties | count of counties left out for a withheld smoking count | named counties outside California and Virginia | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| gap_2018 | 4.6 | percentage points | difference of two pooled shares; shared bootstrap draws over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; lowest-income third minus highest-income third of counties | 2018 | 95% CI 3.6 to 5.6 | 530 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| gap_2024 | 2.1 | percentage points | difference of two pooled shares; shared bootstrap draws over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; lowest-income third minus highest-income third of counties | 2024 | 95% CI 1.7 to 2.6 | 530 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| gap_change | 2.4 | percentage points | fall in the difference of two pooled shares; shared bootstrap draws over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; lowest-income third minus highest-income third of counties | 2018 to 2024 | 95% CI 1.8 to 3.1 | 530 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| i2_pu | 70% | percent of the variation in state slopes beyond sampling error | I-squared of Cochran's Q for state slopes in points, each county counts once | states with a slope of their own | births in 2018 to 2024 |   | 26 states | none (each county counts once) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| i2_pw | 52% | percent of the variation in state slopes beyond sampling error | I-squared of Cochran's Q for state slopes in points, weighted by births with a known tobacco answer | states with a slope of their own | births in 2018 to 2024 |   | 26 states | births with a known tobacco answer | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| income_step | 10% | percent | the step in county income that the proportional slopes use (a definition) | county median household income | all years (a definition) |   |   | none (definition) | County Health Rankings |   |
| k_floor | 8 | counties | fewest complete counties a state needs for a slope of its own (a choice) | complete counties in a state | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| kept_income_median | $72,077 | dollars | median of the county median household incomes of the complete counties | named counties outside California | income for 2022 |   | 530 counties | none (county values) | County Health Rankings | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| lien_lbw_factor | 2 | times the chance of low birth weight | instrumental-variable estimate, pooled across the tax experiments, of the multiple by which smoking in pregnancy raises the chance of low birth weight; the abstract states that smoking 'doubles the chance' | births in the states and control states of Lien and Evans (2005) | study period of Lien and Evans (2005) |   |   | not reported in the abstract | Published estimates from cited studies |   |
| lien_states | 4 | states | number of states with large cigarette tax increases compared with matched control states in Lien and Evans (2005), as reported in the paper's abstract | states that adopted large cigarette tax increases in the study of Lien and Evans (2005) | study period of Lien and Evans (2005) |   | 4 states | none (count of states studied) | Published estimates from cited studies |   |
| map_gray | 2,613 | counties | count of counties drawn gray | counties on the book's county map | births in 2018 to 2024 |   | 2,613 counties | none (full count) | CDC WONDER natality |   |
| map_gray_off | 2,563 | counties | count of gray counties that WONDER does not name (below its size threshold) | counties on the book's county map | births in 2018 to 2024 |   | 2,563 counties | none (full count) | CDC WONDER natality |   |
| markowitz_high | 0.9 | percentage points | Markowitz and coauthors (2017), Table 2: difference-in-differences coefficient of tobacco use during pregnancy on a high state Earned Income Tax Credit without a refund, relative to states with none; the coefficient is +0.009 with a standard error of 0.005, significant at the 10 percent level only | singleton births in 1995 to 2013 to mothers aged 18 or older with a high-school education or less, in the 50 states and DC except Maryland, from birth certificates | births in 1995 to 2013 |   | 25,998,369 births | none (all births) | Published estimates from cited studies |   |
| markowitz_low | 1.6 | percentage points | Markowitz and coauthors (2017), Table 2: difference-in-differences coefficient (linear probability model, state and year-by-quarter fixed effects, standard errors clustered by state) of tobacco use during pregnancy on a low state Earned Income Tax Credit without a refund, relative to states with none; the coefficient is -0.016 with a standard error of 0.004 | singleton births in 1995 to 2013 to mothers aged 18 or older with a high-school education or less, in the 50 states and DC except Maryland, from birth certificates | births in 1995 to 2013 |   | 25,998,369 births | none (all births) | Published estimates from cited studies |   |
| n_ca | 35 | counties | count of counties left out for partial reporting of the tobacco item | California counties among the named counties | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| n_complete | 530 | counties | count of complete counties | named counties outside California with a published smoking count in every year | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| n_dropped | 13 | counties | count of counties with a withheld smoking count (fewer than 10 smoking births) in at least one year, left out of every estimate | named counties outside California | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| n_fe_states | 45 | states | count of states that contribute to a within-state slope | states and the District of Columbia with at least two complete counties | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| n_named | 578 | counties | count of counties | counties that WONDER natality names in every year from 2018 to 2024 and that have births | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| n_states_complete | 49 | states | count of states and the District of Columbia | the 50 states and the District of Columbia, except California, with at least one complete county | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| named_share | 79.5% | percent of live births in the United States | share of births in the named counties | live births in the 50 states and DC | births in 2018 to 2024 |   | 578 counties | none (full count) | CDC WONDER natality |   |
| nr_cells | 4,046 | county-years | count of county-years in which the Not Reported category is a published zero | named counties, 2018 to 2024, in the tobacco cut | births in 2018 to 2024 |   | 578 counties | none (full count) | CDC WONDER natality |   |
| p_het_pu | 0.009 | p-value | wild-bootstrap p-value of Cochran's Q for equal state slopes in percentage points, each county counts once | states with a slope of their own | births in 2018 to 2024 |   | 26 states | none (each county counts once) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| p_het_pw | 0.108 | p-value | wild-bootstrap p-value of Cochran's Q for equal state slopes in percentage points, weighted by births with a known tobacco answer | states with a slope of their own | births in 2018 to 2024 |   | 26 states | births with a known tobacco answer | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| p_het_ru | 0.343 | p-value | wild-bootstrap p-value of Cochran's Q for equal state slopes in proportion (ln share), each county counts once | states with a slope of their own | births in 2018 to 2024 |   | 26 states | none (each county counts once) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| p_het_rw | 0.664 | p-value | wild-bootstrap p-value of Cochran's Q for equal state slopes in proportion (ln share), weighted by births with a known tobacco answer | states with a slope of their own | births in 2018 to 2024 |   | 26 states | births with a known tobacco answer | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| p_prop_min | 0.319 | p-value | wild-bootstrap p-value of Cochran's Q for equal state slopes: smallest p-value across the cutoffs and both weightings, slopes in proportion | states with a slope of their own | births in 2018 to 2024 |   |   | see estimand | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| p_pu_cut_lo | 0.264 | p-value | wild-bootstrap p-value of Cochran's Q for equal state slopes: p-value at the smallest cutoff, slopes in points, each county counting once | states with a slope of their own | births in 2018 to 2024 |   |   | see estimand | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| p_pu_max | 0.009 | p-value | wild-bootstrap p-value of Cochran's Q for equal state slopes: largest p-value across the cutoffs above the smallest, slopes in points, each county counting once | states with a slope of their own | births in 2018 to 2024 |   |   | see estimand | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| p_pw_max | 0.165 | p-value | wild-bootstrap p-value of Cochran's Q for equal state slopes: largest p-value across the cutoffs, slopes in points, weighted by births | states with a slope of their own | births in 2018 to 2024 |   |   | see estimand | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| p_pw_min | 0.108 | p-value | wild-bootstrap p-value of Cochran's Q for equal state slopes: smallest p-value across the cutoffs, slopes in points, weighted by births | states with a slope of their own | births in 2018 to 2024 |   |   | see estimand | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| pct_within_u | 16.7% | percent difference in the smoking share for a 10 percent higher county median household income | state fixed-effects slope of ln(smoking share) on log2 county income, each county counts once, expressed for a 10 percent higher income; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope within states | births in 2018 to 2024 | 95% CI 14.4% to 19.0% | 45 states | none (each county counts once); interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| pct_within_w | 12.0% | percent difference in the smoking share for a 10 percent higher county median household income | state fixed-effects slope of ln(smoking share) on log2 county income, weighted by births with a known tobacco answer, expressed for a 10 percent higher income; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope within states | births in 2018 to 2024 | 95% CI 8.2% to 17.0% | 45 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| ratio_2018 | 2.3 | ratio of shares | ratio of two pooled shares; shared bootstrap draws over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; lowest-income third over highest-income third of counties | 2018 | 95% CI 1.9 to 2.7 | 530 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| ratio_2024 | 2.9 | ratio of shares | ratio of two pooled shares; shared bootstrap draws over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; lowest-income third over highest-income third of counties | 2024 | 95% CI 2.4 to 3.5 | 530 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| ratio_change | 0.6 | ratio of shares | rise in the ratio of two pooled shares; shared bootstrap draws over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; lowest-income third over highest-income third of counties | 2018 to 2024 | 95% CI 0.4 to 0.9 | 530 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| sens_added_2018 | 9 | counties | count of counties added back | named counties outside California with a published Yes count in 2018 that are left out of the complete counties | 2018 |   | 9 counties | none (full count) | CDC WONDER natality |   |
| sens_added_2024 | 1 | counties | count of counties added back | named counties outside California with a published Yes count in 2024 that are left out of the complete counties | 2024 |   | 1 counties | none (full count) | CDC WONDER natality |   |
| sens_slope_2018 | 4.8 | percentage points per doubling of county median household income | state fixed-effects slope of the smoking share on log2 county income, births-weighted, adding back counties left out only for a withheld count in other years; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; counties outside California with a published Yes count in 2018, slope within states | 2018 | 95% CI 3.4 to 6.8 | 45 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| share_all_2018 | 5.4% | percent of births with a known answer | pooled share of births to mothers who reported smoking; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | 2018 | 95% CI 4.9% to 5.9% | 530 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality |   |
| share_all_2024 | 1.9% | percent of births with a known answer | pooled share of births to mothers who reported smoking; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | 2024 | 95% CI 1.7% to 2.1% | 530 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality |   |
| slope_between_u | 5.3 | percentage points per doubling of county median household income | least-squares slope of state means of the smoking share (percent) on log2 county income, each county counts once; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope between states | births in 2018 to 2024 | 95% CI 2.2 to 8.7 | 49 states | none (each county counts once); interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| slope_between_w | 4.7 | percentage points per doubling of county median household income | least-squares slope of state means of the smoking share (percent) on log2 county income, weighted by births with a known tobacco answer; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope between states | births in 2018 to 2024 | 95% CI 1.8 to 8.3 | 49 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| slope_pct_2018 | 10.1% | percent difference in the smoking share for a 10 percent higher county median household income | state fixed-effects slope of ln(smoking share) on log2 county income, births-weighted, expressed for a 10 percent higher income; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope within states | 2018 | 95% CI 6.3% to 15.1% | 45 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| slope_pct_2024 | 14.7% | percent difference in the smoking share for a 10 percent higher county median household income | state fixed-effects slope of ln(smoking share) on log2 county income, births-weighted, expressed for a 10 percent higher income; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope within states | 2024 | 95% CI 11.6% to 19.3% | 45 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| slope_pct_change | 4.5 | percentage points of the percent difference in the smoking share for a 10 percent higher county median household income | fall from 2018 to 2024 in the state fixed-effects proportional slope (a steeper slope), births-weighted; shared bootstrap draws over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope within states | 2018 to 2024 | 95% CI 3.3 to 5.8 | 45 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| slope_pooled_u | 6.2 | percentage points per doubling of county median household income | least-squares slope of the smoking share (percent) on log2 county income, each county counts once; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope across all counties | births in 2018 to 2024 | 95% CI 4.6 to 8.0 | 49 states | none (each county counts once); interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| slope_pooled_w | 4.1 | percentage points per doubling of county median household income | least-squares slope of the smoking share (percent) on log2 county income, weighted by births with a known tobacco answer; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope across all counties | births in 2018 to 2024 | 95% CI 2.7 to 5.9 | 49 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| slope_pts_2018 | 4.9 | percentage points per doubling of county median household income | state fixed-effects slope of the smoking share (percent) on log2 county income, births-weighted; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope within states | 2018 | 95% CI 3.5 to 7.0 | 45 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| slope_pts_2024 | 2.4 | percentage points per doubling of county median household income | state fixed-effects slope of the smoking share (percent) on log2 county income, births-weighted; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope within states | 2024 | 95% CI 1.7 to 3.4 | 45 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| slope_pts_change | 2.5 | percentage points per doubling of county median household income | rise from 2018 to 2024 in the state fixed-effects slope in points (a shallower slope), births-weighted; shared bootstrap draws over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope within states | 2018 to 2024 | 95% CI 1.7 to 3.7 | 45 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| slope_within_u | 6.6 | percentage points per doubling of county median household income | state fixed-effects slope of the smoking share (percent) on log2 county income, each county counts once; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope within states | births in 2018 to 2024 | 95% CI 5.1 to 8.2 | 45 states | none (each county counts once); interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| slope_within_w | 3.9 | percentage points per doubling of county median household income | state fixed-effects slope of the smoking share (percent) on log2 county income, weighted by births with a known tobacco answer; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; slope within states | births in 2018 to 2024 | 95% CI 2.7 to 5.5 | 45 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| small_slope | 8.3 | percentage points per doubling of county median household income | state fixed-effects slope among the smaller half of counties by births with a known answer, each county counting once; bootstrap interval over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; the smaller half of counties by births | births in 2018 to 2024 | 95% CI 6.3 to 10.2 | 42 states | none (each county counts once); interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| split_diff | 4.6 | percentage points per doubling of county median household income | within-state slope among the larger half of counties minus the slope among the smaller half (a shallower slope in the larger half), each county counting once; shared bootstrap draws over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | births in 2018 to 2024 | 95% CI 2.5 to 6.6 | 49 states | none (each county counts once); interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| states_above | 0 | states | count of states whose 95% interval lies above zero, counties weighted by births | states with a slope of their own | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| states_above_u | 0 | states | count of states whose 95% interval lies above zero, each county counting once | states with a slope of their own | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| states_below | 10 | states | count of states whose 95% interval lies below zero, counties weighted by births | states with a slope of their own | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| states_below_prop | 8 | states | count of states whose 95% interval for the slope in proportion lies below zero, counties weighted by births | states with a slope of their own | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| states_below_prop_u | 12 | states | count of states whose 95% interval for the slope in proportion lies below zero, each county counting once | states with a slope of their own | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| states_below_u | 12 | states | count of states whose 95% interval lies below zero, each county counting once | states with a slope of their own | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| states_cut_hi | 23 | states | count of states with a slope of their own | states at the largest cutoff | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| states_cut_lo | 41 | states | count of states with a slope of their own | states at the smallest cutoff | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| states_k | 26 | states | count of states with a slope of their own | states with enough complete counties for a slope of their own | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| states_neg | 26 | states | count of states whose estimated slope is below zero, counties weighted by births | states with a slope of their own | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| states_neg_prop | 25 | states | count of states whose estimated slope in proportion is below zero, counties weighted by births | states with a slope of their own | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| states_neg_prop_u | 26 | states | count of states whose estimated slope in proportion is below zero, each county counting once | states with a slope of their own | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| states_neg_u | 26 | states | count of states whose estimated slope is below zero, each county counting once | states with a slope of their own | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| tau_pu | 3.0 | percentage points per doubling of county median household income | DerSimonian-Laird standard deviation of the true state slopes in points, each county counts once; percentile interval from resampling states | states with a slope of their own | births in 2018 to 2024 | 95% CI 1.6 to 3.6 | 26 states | none (each county counts once) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| tau_pw | 1.9 | percentage points per doubling of county median household income | DerSimonian-Laird standard deviation of the true state slopes in points, weighted by births with a known tobacco answer; percentile interval from resampling states | states with a slope of their own | births in 2018 to 2024 | 95% CI 0.0 to 2.7 | 26 states | births with a known tobacco answer | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| tau_ru | 2.7% | percent of the smoking share for a 10 percent higher county median household income | DerSimonian-Laird standard deviation of the true state slopes of ln share, each county counts once, converted at the 10 percent step; percentile interval from resampling states | states with a slope of their own | births in 2018 to 2024 | 95% CI 0.0% to 7.0% | 26 states | none (each county counts once) | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| tau_rw | 2.1% | percent of the smoking share for a 10 percent higher county median household income | DerSimonian-Laird standard deviation of the true state slopes of ln share, weighted by births with a known tobacco answer, converted at the 10 percent step; percentile interval from resampling states | states with a slope of their own | births in 2018 to 2024 | 95% CI 0.0% to 6.5% | 26 states | births with a known tobacco answer | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| terc_1_2018 | 8.2% | percent of births with a known answer | pooled share of births to mothers who reported smoking in a third of counties by income; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; the lowest-income third of the complete counties by median household income | 2018 | 95% CI 7.3% to 9.2% | 176 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| terc_1_2024 | 3.3% | percent of births with a known answer | pooled share of births to mothers who reported smoking in a third of counties by income; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; the lowest-income third of the complete counties by median household income | 2024 | 95% CI 2.9% to 3.7% | 176 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| terc_2_2018 | 5.5% | percent of births with a known answer | pooled share of births to mothers who reported smoking in a third of counties by income; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; the middle third of the complete counties by median household income | 2018 | 95% CI 4.4% to 6.7% | 177 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| terc_2_2024 | 1.9% | percent of births with a known answer | pooled share of births to mothers who reported smoking in a third of counties by income; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; the middle third of the complete counties by median household income | 2024 | 95% CI 1.5% to 2.3% | 177 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| terc_3_2018 | 3.6% | percent of births with a known answer | pooled share of births to mothers who reported smoking in a third of counties by income; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; the highest-income third of the complete counties by median household income | 2018 | 95% CI 3.2% to 4.0% | 177 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| terc_3_2024 | 1.1% | percent of births with a known answer | pooled share of births to mothers who reported smoking in a third of counties by income; bootstrap interval over counties | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count; the highest-income third of the complete counties by median household income | 2024 | 95% CI 1.0% to 1.3% | 177 counties | none (full counts of births); interval from a bootstrap over counties | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| unk_cells | 3,710 | county-year cells | count of cells | Unknown or Not Stated cells of the complete counties | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| unk_cells_w | 1,794 | county-year cells | count of Unknown or Not Stated cells withheld for holding 1 to 9 births | Unknown or Not Stated cells of the complete counties | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| unk_pub_share | 0.4% | percent of live births | share of births in published Unknown or Not Stated cells | live births in the complete counties | births in 2018 to 2024 |   | 530 counties | none (full count) | CDC WONDER natality |   |
| unk_w_max_share | 0.1% | percent of live births | largest share of births the withheld Unknown or Not Stated cells could hold, at 9 births each | live births in the complete counties | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| va_dropped | 4 | counties | count of counties left out for a withheld smoking count | Virginia counties among the named counties | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| va_named | 15 | counties | count of counties | Virginia counties among the named counties | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| weight_diff | 2.8 | percentage points per doubling of county median household income | within-state slope weighted by births minus the within-state slope with each county counting once (a shallower slope); shared bootstrap draws over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | births in 2018 to 2024 | 95% CI 1.3 to 3.9 | 45 states | births with a known tobacco answer and none (each county counts once); interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| within_minus_pooled_u | −0.4 | percentage points per doubling of county median household income | within-state slope minus the least-squares slope across the counties of the same states with two or more counties, each county counts once; shared bootstrap draws over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | births in 2018 to 2024 | 95% CI −1.3 to 0.5 | 45 states | none (each county counts once); interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. The comparison slope uses only the states with two or more counties, so it differs a little from the slope across all counties printed beside it. |
| within_minus_pooled_w | +0.3 | percentage points per doubling of county median household income | within-state slope minus the least-squares slope across the counties of the same states with two or more counties, weighted by births with a known tobacco answer; shared bootstrap draws over states | live births with a known tobacco answer in the large counties that CDC WONDER names in every year, leaving out California and the counties with a withheld smoking count | births in 2018 to 2024 | 95% CI −0.7 to 1.1 | 45 states | births with a known tobacco answer; interval from a bootstrap over states | CDC WONDER natality | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. The comparison slope uses only the states with two or more counties, so it differs a little from the slope across all counties printed beside it. |
| wonder_suppression_floor | 10 | births | a cell with fewer births than this is withheld (a definition) | the counties and cells of CDC WONDER natality | all years (a definition) |   |   | none (definition) | CDC WONDER natality |   |
| wonder_threshold | 100,000 | residents | population size at which WONDER natality names a county (a definition) | the counties and cells of CDC WONDER natality | all years (a definition) |   |   | none (definition) | CDC WONDER natality |   |
| x_range_median | 0.9 | doublings of county median household income | median across states of the span between the highest and the lowest county median household income, in doublings (log2) | large counties in the states with a slope of their own | income for 2022 |   | 26 states | none (each state counts once) | County Health Rankings | County median household income is the Census SAIPE estimate for 2022 as reported in the County Health Rankings 2024 release; its year differs from the births, which are from 2018 to 2024. |
| yes_w_ca | 33 | county-year cells | count of Yes cells withheld | Yes cells of the California counties | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| yes_w_dropped | 35 | county-year cells | count of Yes cells withheld | Yes cells of the named counties outside California that have a withheld cell | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |
| yes_w_total | 68 | county-year cells | count of Yes cells withheld for holding 1 to 9 births | Yes cells of the named counties | births in 2018 to 2024 |   |   | none (full count) | CDC WONDER natality |   |

## Definitions

- Suppression: The withholding of a number because the count behind it is too small to publish without risking the identification of a person. A suppressed value is missing, not zero.
- Area Deprivation Index (ADI): A score that ranks neighborhoods by income, education, employment and housing conditions drawn from the American Community Survey. In this book a higher national percentile means a more deprived neighborhood.
- Fixed effects: A regression adjustment that gives each group, such as each county, its own baseline. The estimate then rests on differences within groups.
- Ecological inference: Drawing conclusions about individuals from data about places or groups. A pattern across counties need not hold for the people inside them.

## Methods

This chapter compares the share of births with tobacco use reported during pregnancy across counties and states, using county median household income (a 2022 estimate) as the predictor for births in 2018 to 2024, so the outcome and the predictor come from different periods. The counties are those that CDC WONDER names (100,000 residents or more) in every year and that publish every smoking count: California is left out because it does not routinely collect the item, and counties with a withheld smoking count are left out, which removes counties where smoking in pregnancy was rarest. Slopes are shown weighted by births and with each county counting once, and the two weightings differ in size. A state's own slope rests on a handful of complete counties, so state intervals are wide.

### Which births, counties and years are used

Births are counts from CDC WONDER natality for 2018 to 2024 (2024 is final), by county of the mother's residence and by tobacco use during pregnancy, a birth-certificate item with the answers Yes, No, Unknown or Not Stated and Not Reported.

WONDER names a county only if it has 100,000 residents or more. The universe is the 578 counties named in every year, which hold 79.5% of births in the United States in 2018 to 2024. California (35 counties) is left out because WONDER states that California does not routinely collect the item, and its reported share for 2018 is 1.2% against 5.4% in the counties kept.

WONDER withholds cells of 1 to 9 births. A withheld cell is missing, and nothing is derived from a county total minus the published cells. 13 counties outside California have a withheld Yes cell in at least one year (35 cells, which could hold at most 315 births, or 0.05% of smoking births) and are left out of every estimate, so that no county is pooled over only its published years. The 530 complete counties are therefore selected on having at least 10 smoking births in every year, which removes counties where smoking in pregnancy was rarest.

Explains Table 2.

### How the smoking share and county income are defined

A county's smoking share is the Yes births over the Yes plus No births, so births with an Unknown or Not Stated answer are left out of the denominator; the Unknown cells that WONDER publishes hold 0.4% of births, and 1,794 of 3,710 Unknown cells are withheld and could hold at most 0.1%. Not Reported is a published zero in all 4,046 county-years.

County income is the County Health Rankings 2024 release of median household income, a Census Small Area Income and Poverty Estimates value for 2022; a slope is per doubling (log base 2) of income. A slope in proportion is the slope of the natural log of the share, shown as the proportional difference for a 10% higher income. The income measure is checked against the county Area Deprivation Index, the population-weighted mean of tract national ranks.

Explains Table 1 and Table 3.

### How counties are weighted and mapped

Slopes across counties, within states (state fixed effects) and between states (state means) are least-squares slopes, weighted by births with a known answer or unweighted.

Maps draw every county of the book's county map; counties that WONDER does not name, California counties and counties with a withheld count have no value.

Explains Table 4 and Table 2.

### How each state's slope is estimated

A state's own slope is a weighted least-squares line through its complete counties with HC3 standard errors and a t interval with the counties minus two degrees of freedom, for states with at least 8 complete counties, with cutoffs of 3 to 10 as a check.

Explains Table 5 and Table 7.

### How uncertainty is measured

Shares and differences of shares pool births over counties and carry 95% percentile intervals from a bootstrap that resamples whole counties (2,000 replicates, seed 12345) with the same draws for every statistic, so a difference or a ratio has its own interval.

The slopes across counties, within states and between states carry percentile intervals from a bootstrap that resamples whole states with the same replicate count and seed.

### How the test of equal state slopes is run

The test that every state has the same slope is Cochran's Q of the state slopes with their HC3 variances.

Q is too liberal with a handful of counties per state, so its p-value comes from a restricted wild bootstrap (2,000 draws, seed 12345): residuals from a model with a state intercept and one common slope are multiplied by random signs within county, each state's slope and error are refit, and Q is recomputed.

The spread of the true state slopes (tau) is the DerSimonian-Laird estimate with a percentile interval from resampling states.

Explains Table 6.

## What these data cannot show

The comparison is between counties. A county with higher median household income has a lower smoking share, and that says nothing about the income of the mothers who smoked, which these data do not hold. The pattern is ecological and need not hold for the mothers inside the counties. The county tables staged for this book carry one stratifier each, so mother's education cannot be crossed with the tobacco item.

The item is reported at birth. The fall in the share from 5.4% to 1.9% can reflect less smoking, a change in how or whether the item is recorded, or a change in who gives birth, and these data cannot separate them. The item is named tobacco use and may include products other than cigarettes.

The counties are the 530 large counties that remain after the rules above, and they hold 66.9% of the births in the United States. California is out because its item is not collected routinely, and 13 counties are out because their smoking count is withheld in some year, a rule that selects on the outcome. Smaller counties are not in these data, so the chapter says nothing about them. The income measure is an estimate for 2022 and the births are from 2018 to 2024, so a county's income stands in for its income in earlier years. The Area Deprivation Index describes neighborhoods in 2019 to 2023.

State slopes rest on 8 counties or more, and the states with a slope hold 449 counties in all. The intervals use a t distribution and standard errors that allow for unequal variance, and they can be too narrow where one county dominates the line. The tests have little power to detect moderate differences, their p-values depend on how counties are weighted, and a test that finds no difference does not show equality. A slope per doubling of income is a statement about a difference larger than most states' own counties span. None of this identifies why smoking is less common where incomes are higher, and the studies in the box above are the only evidence here on what changes it.

## References

1. Kind, Amy J. H.; Buckingham, William R. (2018). Making Neighborhood-Disadvantage Metrics Accessible: The Neighborhood Atlas. New England Journal of Medicine 378(26): 2456-2458. https://doi.org/10.1056/NEJMp1802313
2. DerSimonian, Rebecca; Laird, Nan (1986). Meta-analysis in clinical trials. Controlled Clinical Trials 7(3): 177-188. https://doi.org/10.1016/0197-2456(86)90046-2
3. Lien, Diana S.; Evans, William N. (2005). Estimating the Impact of Large Cigarette Tax Hikes: The Case of Maternal Smoking and Infant Birth Weight. Journal of Human Resources 40(2): 373-392. https://doi.org/10.3368/jhr.xl.2.373
4. Markowitz, Sara; Komro, Kelli A.; Livingston, Melvin D.; Lenhart, Otto; Wagenaar, Alexander C. (2017). Effects of state-level Earned Income Tax Credit laws in the U.S. on maternal health behaviors and infant health outcomes. Social Science & Medicine 194: 67-75. https://doi.org/10.1016/j.socscimed.2017.10.016

## Provenance

- Pipeline version: 0.1.0
- Build script: book2/chapters/smoking-in-pregnancy/build.py (sha256 a5062d35cd5331f0196777cdcd918ba2a0cba62dc96eade486c10f530f6b2e9d)
- Built on: 2026-10-09
- Site commit: c2b1ff3309cb4a10833f884da91ac0057a66ad0a

Inputs:

| File | Size (bytes) | SHA-256, first 1 MB | SHA-256, last 1 MB |
| --- | ---: | --- | --- |
| book2/chapters/smoking-in-pregnancy/sip_data.py | 24,571 | 85ab524c0eaa61ed20c058c3505a16de76596a87f6b80e4d6c430577684906bd | 85ab524c0eaa61ed20c058c3505a16de76596a87f6b80e4d6c430577684906bd |
| data/analytic/tract_atlas.parquet | 39,659,925 | 29d5e4d943552d54aeb6ba92aadc939d9bd15bdea553c78357dbd516757be627 | 1e10d1ecf722340f23ee2212d4999a90250f85b65fa89b39e32db06d9472e22e |
| data/staged/births/wonder_natality_county_tobacco_2018_2024.parquet | 62,751 | 6379d39b84b8a4e18190d709e9511be66b829bf96458cf22f6a10eb590655942 | 6379d39b84b8a4e18190d709e9511be66b829bf96458cf22f6a10eb590655942 |
| data/staged/births/wonder_natality_county_total_2018_2024.parquet | 41,774 | e85d351fa72c022a05415d332185113b6badcaff1119da1d6f45c76ffe16d86d | e85d351fa72c022a05415d332185113b6badcaff1119da1d6f45c76ffe16d86d |
| data/staged/crosswalks/ct_tract2020_to_old_county.parquet | 15,842 | 961ef39f31596ef65fca2c67d5f2f63e533c5dc9b49745d3bb6437844e4b831d | 961ef39f31596ef65fca2c67d5f2f63e533c5dc9b49745d3bb6437844e4b831d |
| data/staged/health/chr_county_2024.parquet | 8,776,933 | 619795f7ecfec8aff10694b649eaee5e421dbeffbe4be47af4161b51ceefa5cd | c69357f1bcf630407bb9716cb445618838999558c019aaaf77d4681b6bf45c56 |

Outputs:

| File | SHA-256 |
| --- | --- |
| facts.json | 128b072e108ff98bab967e8063031b21551dd5ab3bc6cf2918cdb9cba0215685 |
| figures/cutoff_sensitivity.json | 9bf7678cb6c2b7281532cc86889a6e85c4b2cbc221aaf329e5e2d378ee417bd4 |
| figures/slope_over_time.json | 22c552ec11a5911831aa56ff64592a637503074d03ad19e46c4aa9ebced39e5f |
| figures/slope_scope.json | ace5141f10c487a76f6db7bda4aeead9fd5daf91ff23b2a7915d3d4d3df4bf4b |
| figures/slope_vs_state_level.json | 6e00e027abf060e3ea68b7473beb1d5ae80bd7c574821db95822a9577dde3596 |
| figures/smoking_by_income_third.json | 916b60b8b87dd77d63ea9399f01dbeb788d0688a0c1d9b7f7ba2ebf3229d0a46 |
| figures/smoking_county_map.json | 11e1e14d276808a8a32c0e0b308a551c8da8baf4d572f719589401f87ca3fa1c |
| figures/smoking_vs_income_counties.json | 12535608e983a077c14ffa39e4fb2771c99568dd51c9d67217e0a6e4c0a1bd56 |
| figures/state_slopes.json | 6cb080958e80681716e748a636b84e1411d3130951cbef9baa0d59e00d2d3b97 |
| meta.json | 0f8a7932d763bf6b1a387af88314667d476d97ee553ec406dec3cf16289b5c32 |
| public/data/smoking-in-pregnancy/smoking_county_map.json | 4fa8bb6972d26a2b55aab377d7b36439403dd9de1682680a8138cd9ff352bf26 |
| refs.json | 9a26cfa02db10a18a31e2564582d45b961c08791d993ff5a7f9f522a74e1fc25 |

## Machine formats

- Report (HTML): https://vishalsingh.org/zipcode/smoking-in-pregnancy/report
- Report (Markdown): https://vishalsingh.org/zipcode/smoking-in-pregnancy/report.md
- Every estimate (JSON): https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/facts.json
- Table 1, figure "smoking_by_income_third" (JSON): https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/smoking_by_income_third.json
- Table 2, figure "smoking_county_map" (JSON): https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/smoking_county_map.json
- Table 3, figure "smoking_vs_income_counties" (JSON): https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/smoking_vs_income_counties.json
- Table 4, figure "slope_scope" (JSON): https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/slope_scope.json
- Table 5, figure "state_slopes" (JSON): https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/state_slopes.json
- Table 6, figure "slope_vs_state_level" (JSON): https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/slope_vs_state_level.json
- Table 7, figure "cutoff_sensitivity" (JSON): https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/cutoff_sensitivity.json
- Table 8, figure "slope_over_time" (JSON): https://vishalsingh.org/zipcode/report/smoking-in-pregnancy/figures/slope_over_time.json
- Payload of "smoking_county_map" (JSON): https://vishalsingh.org/zipcode/data/smoking-in-pregnancy/smoking_county_map.json
- Index of every report: https://vishalsingh.org/zipcode/llms.txt; all reports in one file: https://vishalsingh.org/zipcode/llms-full.txt