{
  "alt": "Line chart of the slope of the Democratic two-party share on county college share for the presidential elections of 2000 to 2024, vote-weighted and county-equal. Both lines rise from 2000 to 2008, stay level to 2012, rise to 2016 and change little afterward. The vote-weighted line runs from {fact:slope_w_2000} to {fact:slope_w_2024} and the county-equal line from {fact:slope_u_2000} to {fact:slope_u_2024}, below the vote-weighted line in every election. The correlation view shows both series rising through 2024.",
  "caption": "The slope rises from 2000 to 2008, stays level to 2012 and rises again to 2016. Vote-weighted it does not change after 2016, although adjusted versions of the slope rise by {fact:adj_step_min_w} to {fact:adj_step_max_w} points in those years (see the sensitivity figure); counting each county once, it is below the vote-weighted slope in every election and the gap between the two is smaller in 2024 than in 2000. The line plots, for each election, the least-squares slope of the county Democratic share on county college share, per {fact:x_unit} points of college share; the solid line counts counties by their two-party votes and the dashed line counts each county once; bands are 95% intervals from resampling states.",
  "data": [
    {
      "conf_high": 5.14341,
      "conf_low": 2.4521,
      "estimate": 3.86659,
      "measure": "Slope",
      "n_units": 3114,
      "weighting": "Vote-weighted",
      "year": 2000
    },
    {
      "conf_high": 6.38472,
      "conf_low": 3.90178,
      "estimate": 5.18169,
      "measure": "Slope",
      "n_units": 3113,
      "weighting": "Vote-weighted",
      "year": 2004
    },
    {
      "conf_high": 7.02222,
      "conf_low": 4.72923,
      "estimate": 5.94179,
      "measure": "Slope",
      "n_units": 3113,
      "weighting": "Vote-weighted",
      "year": 2008
    },
    {
      "conf_high": 7.0035,
      "conf_low": 4.88967,
      "estimate": 5.99411,
      "measure": "Slope",
      "n_units": 3112,
      "weighting": "Vote-weighted",
      "year": 2012
    },
    {
      "conf_high": 10.2616,
      "conf_low": 8.22983,
      "estimate": 9.2304,
      "measure": "Slope",
      "n_units": 3113,
      "weighting": "Vote-weighted",
      "year": 2016
    },
    {
      "conf_high": 10.3029,
      "conf_low": 8.51665,
      "estimate": 9.34542,
      "measure": "Slope",
      "n_units": 3105,
      "weighting": "Vote-weighted",
      "year": 2020
    },
    {
      "conf_high": 10.115,
      "conf_low": 8.41973,
      "estimate": 9.2158,
      "measure": "Slope",
      "n_units": 3103,
      "weighting": "Vote-weighted",
      "year": 2024
    },
    {
      "conf_high": 2.98614,
      "conf_low": 0.0885428,
      "estimate": 1.56162,
      "measure": "Slope",
      "n_units": 3114,
      "weighting": "County-equal",
      "year": 2000
    },
    {
      "conf_high": 4.58134,
      "conf_low": 1.96473,
      "estimate": 3.29591,
      "measure": "Slope",
      "n_units": 3113,
      "weighting": "County-equal",
      "year": 2004
    },
    {
      "conf_high": 6.14976,
      "conf_low": 4.06103,
      "estimate": 5.11495,
      "measure": "Slope",
      "n_units": 3113,
      "weighting": "County-equal",
      "year": 2008
    },
    {
      "conf_high": 6.35556,
      "conf_low": 3.92712,
      "estimate": 5.15391,
      "measure": "Slope",
      "n_units": 3112,
      "weighting": "County-equal",
      "year": 2012
    },
    {
      "conf_high": 9.36042,
      "conf_low": 6.48388,
      "estimate": 7.95041,
      "measure": "Slope",
      "n_units": 3113,
      "weighting": "County-equal",
      "year": 2016
    },
    {
      "conf_high": 10.0346,
      "conf_low": 7.31106,
      "estimate": 8.72743,
      "measure": "Slope",
      "n_units": 3105,
      "weighting": "County-equal",
      "year": 2020
    },
    {
      "conf_high": 9.78965,
      "conf_low": 7.23635,
      "estimate": 8.59187,
      "measure": "Slope",
      "n_units": 3103,
      "weighting": "County-equal",
      "year": 2024
    },
    {
      "conf_high": 0.365013,
      "conf_low": 0.189,
      "estimate": 0.281836,
      "measure": "Correlation",
      "n_units": 3114,
      "weighting": "Vote-weighted",
      "year": 2000
    },
    {
      "conf_high": 0.453279,
      "conf_low": 0.297364,
      "estimate": 0.37788,
      "measure": "Correlation",
      "n_units": 3113,
      "weighting": "Vote-weighted",
      "year": 2004
    },
    {
      "conf_high": 0.490658,
      "conf_low": 0.357037,
      "estimate": 0.426998,
      "measure": "Correlation",
      "n_units": 3113,
      "weighting": "Vote-weighted",
      "year": 2008
    },
    {
      "conf_high": 0.47844,
      "conf_low": 0.350826,
      "estimate": 0.415066,
      "measure": "Correlation",
      "n_units": 3112,
      "weighting": "Vote-weighted",
      "year": 2012
    },
    {
      "conf_high": 0.637285,
      "conf_low": 0.528375,
      "estimate": 0.577163,
      "measure": "Correlation",
      "n_units": 3113,
      "weighting": "Vote-weighted",
      "year": 2016
    },
    {
      "conf_high": 0.692854,
      "conf_low": 0.593946,
      "estimate": 0.637255,
      "measure": "Correlation",
      "n_units": 3105,
      "weighting": "Vote-weighted",
      "year": 2020
    },
    {
      "conf_high": 0.713436,
      "conf_low": 0.621296,
      "estimate": 0.663034,
      "measure": "Correlation",
      "n_units": 3103,
      "weighting": "Vote-weighted",
      "year": 2024
    },
    {
      "conf_high": 0.196374,
      "conf_low": 0.00529164,
      "estimate": 0.0993572,
      "measure": "Correlation",
      "n_units": 3114,
      "weighting": "County-equal",
      "year": 2000
    },
    {
      "conf_high": 0.304492,
      "conf_low": 0.117789,
      "estimate": 0.21088,
      "measure": "Correlation",
      "n_units": 3113,
      "weighting": "County-equal",
      "year": 2004
    },
    {
      "conf_high": 0.395412,
      "conf_low": 0.230595,
      "estimate": 0.309805,
      "measure": "Correlation",
      "n_units": 3113,
      "weighting": "County-equal",
      "year": 2008
    },
    {
      "conf_high": 0.397934,
      "conf_low": 0.218921,
      "estimate": 0.30511,
      "measure": "Correlation",
      "n_units": 3112,
      "weighting": "County-equal",
      "year": 2012
    },
    {
      "conf_high": 0.564459,
      "conf_low": 0.355404,
      "estimate": 0.459906,
      "measure": "Correlation",
      "n_units": 3113,
      "weighting": "County-equal",
      "year": 2016
    },
    {
      "conf_high": 0.626292,
      "conf_low": 0.426503,
      "estimate": 0.529751,
      "measure": "Correlation",
      "n_units": 3105,
      "weighting": "County-equal",
      "year": 2020
    },
    {
      "conf_high": 0.656216,
      "conf_low": 0.451746,
      "estimate": 0.558693,
      "measure": "Correlation",
      "n_units": 3103,
      "weighting": "County-equal",
      "year": 2024
    }
  ],
  "id": "gradient_by_year",
  "notes": [
    "Election returns are full counts of votes, so they carry no sampling error. The 95% intervals come from a bootstrap that resamples whole states, so they show how much a number depends on which states are in the set. They do not include the sampling error of the county college shares, which are census and American Community Survey estimates interpolated between years.",
    "{fact:n_counties_2000} counties in 2000 and {fact:n_counties_2024} in 2024; Alaska and counties without college share are left out, and in 2024 the votes of Kansas City are added to Jackson County, Missouri. See Methods."
  ],
  "source": "County presidential returns, 2000-2024 (Algara and Amlani; MIT Election Data and Science Lab), full counts of votes, and county demographics (decennial census and American Community Survey estimates interpolated to election years); weighted by two-party votes in the election or county-equal, as stated",
  "spec": {
    "annotations": [
      {
        "label": "Largest step",
        "type": "band",
        "x1": 2012,
        "x2": 2016
      }
    ],
    "colors": {
      "County-equal": "highlight",
      "Vote-weighted": "total"
    },
    "dashed": [
      "County-equal"
    ],
    "hi": "conf_high",
    "lo": "conf_low",
    "n": "n_units",
    "series": "weighting",
    "x": "year",
    "xDomain": [
      2000,
      2024
    ],
    "xFormat": {
      "digits": 0
    },
    "xLabel": "Presidential election",
    "xTicks": "data",
    "y": "estimate",
    "yDomain": [
      0,
      12
    ],
    "yFormat": {
      "digits": 1
    },
    "yLabel": "Points of Democratic two-party share per 10 points of college share"
  },
  "subtitle": "Slope of a county's Democratic share of the two-party presidential vote on the share of its residents 25 and older with a bachelor's degree or more, 2000 to 2024, vote-weighted and county-equal",
  "title": "Vote-weighted, the slope of the vote on county college share rose from {fact:slope_w_2000} to {fact:slope_w_2024} points per {fact:x_unit} points of college share, in steps before 2008 and between 2012 and 2016",
  "type": "line",
  "views": [
    {
      "filter": {
        "measure": "Slope"
      },
      "id": "slope",
      "label": "Slope"
    },
    {
      "caption": "The vote-weighted correlation is higher in each election after 2012, although the vote-weighted slope is level from 2016. A correlation equals the slope times the spread of college share divided by the spread of the Democratic share across counties, and from 2016 to 2024 the vote-weighted standard deviation of college share rose from {fact:sd_ba_w_2016} to {fact:sd_ba_w_2024} points while that of the Democratic share fell from {fact:sd_ds_w_2016} to {fact:sd_ds_w_2024}. The solid line counts counties by their two-party votes and the dashed line counts each county once; bands are 95% intervals from resampling states.",
      "filter": {
        "measure": "Correlation"
      },
      "id": "corr",
      "label": "Correlation",
      "spec": {
        "annotations": [
          {
            "label": "Largest step in the slope",
            "type": "band",
            "x1": 2012,
            "x2": 2016
          }
        ],
        "yDomain": [
          0,
          0.8
        ],
        "yFormat": {
          "digits": 2
        },
        "yLabel": "Correlation of college share with the Democratic share"
      },
      "title": "Vote-weighted, the correlation kept rising from {fact:corr_w_2016} in 2016 to {fact:corr_w_2024} in 2024 while the slope did not change"
    }
  ],
  "width": "wide"
}