{
  "alt": "Two lines with confidence bands show the in-party premium in the ANES from 1980 to 2024 and in the CES from 2006 to 2024, with a reference line at zero. Through 2008 the ANES line runs from {fact:anes_prem_1990} points in 1990 to {fact:anes_prem_1984} in 1984, and it stays between {fact:prem_late_min} and {fact:prem_late_max} from 2012 on; the CES line reaches its lowest value, {fact:ces_prem_2008} points, in 2008 and its highest, {fact:ces_prem_2006}, in 2006. Two dashed segments mark the ANES averages, {fact:prem_early} points for 1980 to 1990 and {fact:prem_late} for 2012 to 2024.",
  "caption": "The ANES premium is higher from 2012 on than from 1980 to 1990, and the CES premium is higher than the ANES premium in each year from 2012 on in which both ask the item. Dashed segments mark the ANES average of the yearly premiums: {fact:prem_early} points for 1980 to 1990 and {fact:prem_late} for 2012 to 2024. Bands are 95% intervals.",
  "data": [
    {
      "conf_high": 3.40461,
      "conf_low": -0.583293,
      "n": 1341,
      "premium": 1.41066,
      "president": "Carter",
      "series": "ANES",
      "year": 1980
    },
    {
      "conf_high": 20.4851,
      "conf_low": 11.8396,
      "n": 1193,
      "premium": 16.1623,
      "president": "Reagan",
      "series": "ANES",
      "year": 1982
    },
    {
      "conf_high": 42.1454,
      "conf_low": 33.7768,
      "n": 1881,
      "premium": 37.9611,
      "president": "Reagan",
      "series": "ANES",
      "year": 1984
    },
    {
      "conf_high": 18.6455,
      "conf_low": 10.5157,
      "n": 1798,
      "premium": 14.5806,
      "president": "Reagan",
      "series": "ANES",
      "year": 1986
    },
    {
      "conf_high": 22.0586,
      "conf_low": 14.597,
      "n": 1721,
      "premium": 18.3278,
      "president": "Reagan",
      "series": "ANES",
      "year": 1988
    },
    {
      "conf_high": 1.95368,
      "conf_low": -1.62973,
      "n": 1710,
      "premium": 0.161972,
      "president": "Bush",
      "series": "ANES",
      "year": 1990
    },
    {
      "conf_high": 7.62525,
      "conf_low": 3.68166,
      "n": 2135,
      "premium": 5.65346,
      "president": "Bush",
      "series": "ANES",
      "year": 1992
    },
    {
      "conf_high": 9.25407,
      "conf_low": -1.23526,
      "n": 1560,
      "premium": 4.00941,
      "president": "Clinton",
      "series": "ANES",
      "year": 1994
    },
    {
      "conf_high": 27.6352,
      "conf_low": 17.0544,
      "n": 1537,
      "premium": 22.3448,
      "president": "Clinton",
      "series": "ANES",
      "year": 1996
    },
    {
      "conf_high": 21.6213,
      "conf_low": 8.89958,
      "n": 1114,
      "premium": 15.2604,
      "president": "Clinton",
      "series": "ANES",
      "year": 1998
    },
    {
      "conf_high": 28.5089,
      "conf_low": 18.1091,
      "n": 1555,
      "premium": 23.309,
      "president": "Clinton",
      "series": "ANES",
      "year": 2000
    },
    {
      "conf_high": 5.92672,
      "conf_low": 0.171221,
      "n": 1368,
      "premium": 3.04897,
      "president": "Bush",
      "series": "ANES",
      "year": 2002
    },
    {
      "conf_high": 38.0133,
      "conf_low": 26.9858,
      "n": 1064,
      "premium": 32.4995,
      "president": "Bush",
      "series": "ANES",
      "year": 2004
    },
    {
      "conf_high": 3.9969,
      "conf_low": 0.313325,
      "n": 2013,
      "premium": 2.15511,
      "president": "Bush",
      "series": "ANES",
      "year": 2008
    },
    {
      "conf_high": 42.3541,
      "conf_low": 36.4322,
      "n": 5083,
      "premium": 39.3931,
      "president": "Obama",
      "series": "ANES",
      "year": 2012
    },
    {
      "conf_high": 36.9805,
      "conf_low": 30.544,
      "n": 3660,
      "premium": 33.7622,
      "president": "Obama",
      "series": "ANES",
      "year": 2016
    },
    {
      "conf_high": 33.3342,
      "conf_low": 28.6688,
      "n": 7254,
      "premium": 31.0015,
      "president": "Trump",
      "series": "ANES",
      "year": 2020
    },
    {
      "conf_high": 34.7901,
      "conf_low": 28.7874,
      "n": 4877,
      "premium": 31.7887,
      "president": "Biden",
      "series": "ANES",
      "year": 2024
    },
    {
      "conf_high": 63.998,
      "conf_low": 62.1086,
      "n": 31314,
      "premium": 63.0533,
      "president": "Bush",
      "series": "CES",
      "year": 2006
    },
    {
      "conf_high": 25.5627,
      "conf_low": 21.5077,
      "n": 7911,
      "premium": 23.5352,
      "president": "Bush",
      "series": "CES",
      "year": 2007
    },
    {
      "conf_high": 1.61065,
      "conf_low": 0.930515,
      "n": 28482,
      "premium": 1.27058,
      "president": "Bush",
      "series": "CES",
      "year": 2008
    },
    {
      "conf_high": 20.6615,
      "conf_low": 17.6989,
      "n": 11426,
      "premium": 19.1802,
      "president": "Obama",
      "series": "CES",
      "year": 2009
    },
    {
      "conf_high": 31.2203,
      "conf_low": 29.0663,
      "n": 47347,
      "premium": 30.1433,
      "president": "Obama",
      "series": "CES",
      "year": 2010
    },
    {
      "conf_high": 20.9128,
      "conf_low": 17.9512,
      "n": 16450,
      "premium": 19.432,
      "president": "Obama",
      "series": "CES",
      "year": 2011
    },
    {
      "conf_high": 51.675,
      "conf_low": 49.5479,
      "n": 45431,
      "premium": 50.6115,
      "president": "Obama",
      "series": "CES",
      "year": 2012
    },
    {
      "conf_high": 37.6124,
      "conf_low": 33.609,
      "n": 12640,
      "premium": 35.6107,
      "president": "Obama",
      "series": "CES",
      "year": 2013
    },
    {
      "conf_high": 42.0932,
      "conf_low": 39.7517,
      "n": 43938,
      "premium": 40.9225,
      "president": "Obama",
      "series": "CES",
      "year": 2014
    },
    {
      "conf_high": 45.4477,
      "conf_low": 41.2612,
      "n": 11272,
      "premium": 43.3544,
      "president": "Obama",
      "series": "CES",
      "year": 2015
    },
    {
      "conf_high": 44.587,
      "conf_low": 42.6834,
      "n": 50685,
      "premium": 43.6352,
      "president": "Obama",
      "series": "CES",
      "year": 2016
    },
    {
      "conf_high": 50.4318,
      "conf_low": 46.2035,
      "n": 13851,
      "premium": 48.3176,
      "president": "Trump",
      "series": "CES",
      "year": 2017
    },
    {
      "conf_high": 61.0957,
      "conf_low": 59.0345,
      "n": 47590,
      "premium": 60.0651,
      "president": "Trump",
      "series": "CES",
      "year": 2018
    },
    {
      "conf_high": 24.9123,
      "conf_low": 20.918,
      "n": 14444,
      "premium": 22.9152,
      "president": "Trump",
      "series": "CES",
      "year": 2019
    },
    {
      "conf_high": 39.7077,
      "conf_low": 37.6946,
      "n": 48334,
      "premium": 38.7011,
      "president": "Trump",
      "series": "CES",
      "year": 2020
    },
    {
      "conf_high": 39.2765,
      "conf_low": 36.4458,
      "n": 19809,
      "premium": 37.8612,
      "president": "Biden",
      "series": "CES",
      "year": 2021
    },
    {
      "conf_high": 21.6954,
      "conf_low": 19.9928,
      "n": 48285,
      "premium": 20.8441,
      "president": "Biden",
      "series": "CES",
      "year": 2022
    },
    {
      "conf_high": 34.8691,
      "conf_low": 31.9015,
      "n": 19158,
      "premium": 33.3853,
      "president": "Biden",
      "series": "CES",
      "year": 2023
    },
    {
      "conf_high": 48.6756,
      "conf_low": 46.3935,
      "n": 49862,
      "premium": 47.5345,
      "president": "Biden",
      "series": "CES",
      "year": 2024
    },
    {
      "n": 9644,
      "premium": 14.7674,
      "series": "ANES average",
      "year": 1980
    },
    {
      "n": 9644,
      "premium": 14.7674,
      "series": "ANES average",
      "year": 1990
    },
    {
      "premium": null,
      "series": "ANES average",
      "year": 2001
    },
    {
      "n": 20874,
      "premium": 33.9864,
      "series": "ANES average",
      "year": 2012
    },
    {
      "n": 20874,
      "premium": 33.9864,
      "series": "ANES average",
      "year": 2024
    }
  ],
  "id": "premium_trend",
  "notes": [
    "The ANES adds web interviews in 2012; the CES is an online panel throughout. Mode comparisons follow in the chapter.",
    "The averages count each survey once and carry no band here: the interval of an average covers sampling error within each survey only, and the yearly premiums vary by more than that."
  ],
  "source": "American National Election Studies Cumulative Data File, 1980-2024, and Cooperative Election Study cumulative common content, 2006-2024; weighted (VCF0009z for the ANES, year-specific weight for the CES)",
  "spec": {
    "annotations": [
      {
        "label": "No difference between the parties",
        "type": "y-rule",
        "y": 0
      },
      {
        "label": "ANES adds web interviews",
        "type": "x-rule",
        "x": 2012
      }
    ],
    "colors": {
      "ANES": "cat1",
      "ANES average": "cat1",
      "CES": "cat2"
    },
    "dashed": [
      "ANES average"
    ],
    "hi": "conf_high",
    "lo": "conf_low",
    "n": "n",
    "series": "series",
    "x": "year",
    "xDomain": [
      1980,
      2024
    ],
    "xLabel": "Survey year",
    "y": "premium",
    "yDomain": [
      -10,
      70
    ],
    "yFormat": {
      "digits": 0
    },
    "yLabel": "In-party premium (percentage points)"
  },
  "subtitle": "In-party premium, percentage points; partisans including leaners; ANES 1980 to 2024 and CES 2006 to 2024",
  "table": {
    "columns": [
      {
        "key": "year",
        "label": "Survey year"
      },
      {
        "key": "series",
        "label": "Survey"
      },
      {
        "key": "president",
        "label": "President"
      },
      {
        "format": {
          "digits": 1
        },
        "key": "premium",
        "label": "Premium (points)"
      },
      {
        "format": {
          "digits": 1
        },
        "key": "conf_low",
        "label": "Interval low"
      },
      {
        "format": {
          "digits": 1
        },
        "key": "conf_high",
        "label": "Interval high"
      },
      {
        "format": {
          "digits": 0,
          "thousands": true
        },
        "key": "n",
        "label": "n"
      }
    ]
  },
  "title": "The ANES premium averages higher from 2012 on, while the CES premium ranges from {fact:ces_prem_2008} to {fact:ces_prem_2006} points",
  "type": "line",
  "width": "wide"
}