{
  "alt": "Line chart of two vote-weighted correlations of county margins. The correlation with the previous election is {fact:corr1_1896} for 1892 to 1896, {fact:corr1_1964} for 1960 to 1964 and {fact:corr1_1976} for 1972 to 1976, and reaches {fact:corr1_latest} for 2020 to 2024. The correlation with the margin four elections earlier is {fact:corr4_1988} for 1972 to 1988 and {fact:corr4_latest} for 2008 to 2024.",
  "caption": "The solid line stays above {fact:corr_cut} from 1984 to 1988 on and is lowest in 1892 to 1896, at {fact:corr1_1896}. The solid line correlates each county's margin with its margin in the previous election and the dashed line with its margin four elections earlier, both weighted by two-party votes in the later election.",
  "data": [
    {
      "correlation": 0.541888,
      "n": 1687,
      "pair": "1868–72",
      "series": "Previous election",
      "year": 1872
    },
    {
      "correlation": 0.645701,
      "n": 2151,
      "pair": "1872–76",
      "series": "Previous election",
      "year": 1876
    },
    {
      "correlation": 0.886883,
      "n": 2216,
      "pair": "1876–80",
      "series": "Previous election",
      "year": 1880
    },
    {
      "correlation": 0.903375,
      "n": 2283,
      "pair": "1880–84",
      "series": "Previous election",
      "year": 1884
    },
    {
      "correlation": 0.910734,
      "n": 2345,
      "pair": "1884–88",
      "series": "Previous election",
      "year": 1888
    },
    {
      "correlation": 0.820651,
      "n": 2424,
      "pair": "1888–92",
      "series": "Previous election",
      "year": 1892
    },
    {
      "correlation": 0.33416,
      "n": 2654,
      "pair": "1892–96",
      "series": "Previous election",
      "year": 1896
    },
    {
      "correlation": 0.74117,
      "n": 2695,
      "pair": "1896–1900",
      "series": "Previous election",
      "year": 1900
    },
    {
      "correlation": 0.863296,
      "n": 2680,
      "pair": "1900–04",
      "series": "Previous election",
      "year": 1904
    },
    {
      "correlation": 0.897161,
      "n": 2707,
      "pair": "1904–08",
      "series": "Previous election",
      "year": 1908
    },
    {
      "correlation": 0.663942,
      "n": 2832,
      "pair": "1908–12",
      "series": "Previous election",
      "year": 1912
    },
    {
      "correlation": 0.590276,
      "n": 2942,
      "pair": "1912–16",
      "series": "Previous election",
      "year": 1916
    },
    {
      "correlation": 0.820534,
      "n": 3018,
      "pair": "1916–20",
      "series": "Previous election",
      "year": 1920
    },
    {
      "correlation": 0.894888,
      "n": 3048,
      "pair": "1920–24",
      "series": "Previous election",
      "year": 1924
    },
    {
      "correlation": 0.527297,
      "n": 3083,
      "pair": "1924–28",
      "series": "Previous election",
      "year": 1928
    },
    {
      "correlation": 0.684869,
      "n": 3095,
      "pair": "1928–32",
      "series": "Previous election",
      "year": 1932
    },
    {
      "correlation": 0.838173,
      "n": 3095,
      "pair": "1932–36",
      "series": "Previous election",
      "year": 1936
    },
    {
      "correlation": 0.887293,
      "n": 3094,
      "pair": "1936–40",
      "series": "Previous election",
      "year": 1940
    },
    {
      "correlation": 0.967658,
      "n": 3093,
      "pair": "1940–44",
      "series": "Previous election",
      "year": 1944
    },
    {
      "correlation": 0.874331,
      "n": 3095,
      "pair": "1944–48",
      "series": "Previous election",
      "year": 1948
    },
    {
      "correlation": 0.841751,
      "n": 3094,
      "pair": "1948–52",
      "series": "Previous election",
      "year": 1952
    },
    {
      "correlation": 0.896647,
      "n": 3097,
      "pair": "1952–56",
      "series": "Previous election",
      "year": 1956
    },
    {
      "correlation": 0.761149,
      "n": 3100,
      "pair": "1956–60",
      "series": "Previous election",
      "year": 1960
    },
    {
      "correlation": 0.514035,
      "n": 3102,
      "pair": "1960–64",
      "series": "Previous election",
      "year": 1964
    },
    {
      "correlation": 0.550582,
      "n": 3107,
      "pair": "1964–68",
      "series": "Previous election",
      "year": 1968
    },
    {
      "correlation": 0.674213,
      "n": 3109,
      "pair": "1968–72",
      "series": "Previous election",
      "year": 1972
    },
    {
      "correlation": 0.51049,
      "n": 3110,
      "pair": "1972–76",
      "series": "Previous election",
      "year": 1976
    },
    {
      "correlation": 0.85377,
      "n": 3112,
      "pair": "1976–80",
      "series": "Previous election",
      "year": 1980
    },
    {
      "correlation": 0.862258,
      "n": 3112,
      "pair": "1980–84",
      "series": "Previous election",
      "year": 1984
    },
    {
      "correlation": 0.958801,
      "n": 3114,
      "pair": "1984–88",
      "series": "Previous election",
      "year": 1988
    },
    {
      "correlation": 0.939593,
      "n": 3114,
      "pair": "1988–92",
      "series": "Previous election",
      "year": 1992
    },
    {
      "correlation": 0.94294,
      "n": 3114,
      "pair": "1992–96",
      "series": "Previous election",
      "year": 1996
    },
    {
      "correlation": 0.958345,
      "n": 3113,
      "pair": "1996–2000",
      "series": "Previous election",
      "year": 2000
    },
    {
      "correlation": 0.97459,
      "n": 3113,
      "pair": "2000–04",
      "series": "Previous election",
      "year": 2004
    },
    {
      "correlation": 0.963733,
      "n": 3114,
      "pair": "2004–08",
      "series": "Previous election",
      "year": 2008
    },
    {
      "correlation": 0.989076,
      "n": 3114,
      "pair": "2008–12",
      "series": "Previous election",
      "year": 2012
    },
    {
      "correlation": 0.957931,
      "n": 3112,
      "pair": "2012–16",
      "series": "Previous election",
      "year": 2016
    },
    {
      "correlation": 0.987665,
      "n": 3113,
      "pair": "2016–20",
      "series": "Previous election",
      "year": 2020
    },
    {
      "correlation": 0.991657,
      "n": 3111,
      "pair": "2020–24",
      "series": "Previous election",
      "year": 2024
    },
    {
      "correlation": 0.673301,
      "n": 1688,
      "pair": "1868–84",
      "series": "Four elections earlier",
      "year": 1884
    },
    {
      "correlation": 0.499151,
      "n": 2155,
      "pair": "1872–88",
      "series": "Four elections earlier",
      "year": 1888
    },
    {
      "correlation": 0.708932,
      "n": 2227,
      "pair": "1876–92",
      "series": "Four elections earlier",
      "year": 1892
    },
    {
      "correlation": 0.593271,
      "n": 2287,
      "pair": "1880–96",
      "series": "Four elections earlier",
      "year": 1896
    },
    {
      "correlation": 0.755904,
      "n": 2336,
      "pair": "1884–1900",
      "series": "Four elections earlier",
      "year": 1900
    },
    {
      "correlation": 0.783759,
      "n": 2398,
      "pair": "1888–1904",
      "series": "Four elections earlier",
      "year": 1904
    },
    {
      "correlation": 0.555457,
      "n": 2642,
      "pair": "1892–1908",
      "series": "Four elections earlier",
      "year": 1908
    },
    {
      "correlation": 0.533015,
      "n": 2693,
      "pair": "1896–1912",
      "series": "Four elections earlier",
      "year": 1912
    },
    {
      "correlation": 0.806747,
      "n": 2710,
      "pair": "1900–16",
      "series": "Four elections earlier",
      "year": 1916
    },
    {
      "correlation": 0.83015,
      "n": 2720,
      "pair": "1904–20",
      "series": "Four elections earlier",
      "year": 1920
    },
    {
      "correlation": 0.860072,
      "n": 2850,
      "pair": "1908–24",
      "series": "Four elections earlier",
      "year": 1924
    },
    {
      "correlation": 0.281874,
      "n": 2943,
      "pair": "1912–28",
      "series": "Four elections earlier",
      "year": 1928
    },
    {
      "correlation": 0.750263,
      "n": 3020,
      "pair": "1916–32",
      "series": "Four elections earlier",
      "year": 1932
    },
    {
      "correlation": 0.523575,
      "n": 3052,
      "pair": "1920–36",
      "series": "Four elections earlier",
      "year": 1936
    },
    {
      "correlation": 0.572506,
      "n": 3080,
      "pair": "1924–40",
      "series": "Four elections earlier",
      "year": 1940
    },
    {
      "correlation": 0.533232,
      "n": 3094,
      "pair": "1928–44",
      "series": "Four elections earlier",
      "year": 1944
    },
    {
      "correlation": 0.733433,
      "n": 3095,
      "pair": "1932–48",
      "series": "Four elections earlier",
      "year": 1948
    },
    {
      "correlation": 0.688776,
      "n": 3092,
      "pair": "1936–52",
      "series": "Four elections earlier",
      "year": 1952
    },
    {
      "correlation": 0.724362,
      "n": 3091,
      "pair": "1940–56",
      "series": "Four elections earlier",
      "year": 1956
    },
    {
      "correlation": 0.587656,
      "n": 3092,
      "pair": "1944–60",
      "series": "Four elections earlier",
      "year": 1960
    },
    {
      "correlation": 0.0529864,
      "n": 3090,
      "pair": "1948–64",
      "series": "Four elections earlier",
      "year": 1964
    },
    {
      "correlation": 0.653275,
      "n": 3094,
      "pair": "1952–68",
      "series": "Four elections earlier",
      "year": 1968
    },
    {
      "correlation": 0.233106,
      "n": 3095,
      "pair": "1956–72",
      "series": "Four elections earlier",
      "year": 1972
    },
    {
      "correlation": 0.76344,
      "n": 3100,
      "pair": "1960–76",
      "series": "Four elections earlier",
      "year": 1976
    },
    {
      "correlation": 0.450664,
      "n": 3104,
      "pair": "1964–80",
      "series": "Four elections earlier",
      "year": 1980
    },
    {
      "correlation": 0.724405,
      "n": 3108,
      "pair": "1968–84",
      "series": "Four elections earlier",
      "year": 1984
    },
    {
      "correlation": 0.847012,
      "n": 3109,
      "pair": "1972–88",
      "series": "Four elections earlier",
      "year": 1988
    },
    {
      "correlation": 0.64385,
      "n": 3112,
      "pair": "1976–92",
      "series": "Four elections earlier",
      "year": 1992
    },
    {
      "correlation": 0.720665,
      "n": 3111,
      "pair": "1980–96",
      "series": "Four elections earlier",
      "year": 1996
    },
    {
      "correlation": 0.827574,
      "n": 3112,
      "pair": "1984–2000",
      "series": "Four elections earlier",
      "year": 2000
    },
    {
      "correlation": 0.810408,
      "n": 3111,
      "pair": "1988–2004",
      "series": "Four elections earlier",
      "year": 2004
    },
    {
      "correlation": 0.796269,
      "n": 3112,
      "pair": "1992–2008",
      "series": "Four elections earlier",
      "year": 2008
    },
    {
      "correlation": 0.842357,
      "n": 3112,
      "pair": "1996–2012",
      "series": "Four elections earlier",
      "year": 2012
    },
    {
      "correlation": 0.842253,
      "n": 3111,
      "pair": "2000–16",
      "series": "Four elections earlier",
      "year": 2016
    },
    {
      "correlation": 0.863692,
      "n": 3112,
      "pair": "2004–20",
      "series": "Four elections earlier",
      "year": 2020
    },
    {
      "correlation": 0.900433,
      "n": 3112,
      "pair": "2008–24",
      "series": "Four elections earlier",
      "year": 2024
    }
  ],
  "id": "margin_persistence",
  "notes": [
    "Full counts of votes: there is no sampling, so the estimates have no confidence interval.",
    "A county needs returns in both elections to enter a correlation."
  ],
  "source": "County presidential returns, 1868-2024 (Algara and Amlani for 1868-2020, MIT Election Data and Science Lab for 2024); full counts, not survey estimates; county swings weighted by two-party votes in the later election unless stated",
  "spec": {
    "colors": {
      "Four elections earlier": "cat2",
      "Previous election": "cat1"
    },
    "dashed": [
      "Four elections earlier"
    ],
    "n": "n",
    "series": "series",
    "x": "year",
    "xDomain": [
      1868,
      2030
    ],
    "xLabel": "Later election",
    "y": "correlation",
    "yDomain": [
      0,
      1
    ],
    "yFormat": {
      "digits": 1
    },
    "yLabel": "Correlation of county margins"
  },
  "subtitle": "Vote-weighted correlation between a county's two-party margin and its margin in an earlier election, plotted at the later election",
  "table": {
    "columns": [
      {
        "key": "pair",
        "label": "Elections compared"
      },
      {
        "key": "series",
        "label": "Compared with"
      },
      {
        "format": {
          "digits": 3
        },
        "key": "correlation",
        "label": "Correlation"
      },
      {
        "format": {
          "digits": 0,
          "thousands": true
        },
        "key": "n",
        "label": "Counties"
      }
    ]
  },
  "title": "County margins correlated with the previous election's margins above {fact:corr_cut} in {fact:n_corr_early_above} of {fact:n_early} pairs through 1984 and in all {fact:n_late} pairs since",
  "type": "line",
  "width": "wide"
}