placestats

Republican swing, 2000 to 2024 and Friending bias

A county is not a voter. Read either way, this says one thing and no more. Counties that voted more Republican also tend to differ on the other measure, and counties that voted less Republican tend to differ the other way. It does not follow that the people who voted that way are the people with the different score. Making that leap is called the ecological fallacy: reading a pattern across places as a fact about individual people. It is the most common misuse of exactly this data. How a county votes also goes so closely with its density, age and education that much of what looks political here is really those. That is what the adjusted figures are for. The vote shares run from 2000 to 2024, and the links here are measured in 2023.

Where Republican swing, 2000 to 2024 is higher, Friending bias tends to be lower. The link is weak: -0.32 across 2,978 counties, on a scale from −1 (opposite) to +1 (in step). That figure compares places with the same population density, income and education, so those differences can't explain it. It holds inside states too. Measured separately within each of 39 states, the middle value of the link is -0.25.

Holds after adjusting

Every place, plotted

One dot for each place reporting both measures. Hover over or tap a dot to see its name and values. The thin line is the straight line that best fits the dots. The bold line, shown for counties, is the link after adjusting for density, income and education. A dot far from the lines is a place that does not follow the pattern.

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What each measure is

Republican swing, 2000 to 2024

The change in the Republican share of the two-party presidential vote from 2000 to 2024, in percentage points. Positive means the area moved toward Republicans. That is a different question from which party it votes for.

MIT Election Data and Science Lab · MIT county presidential returns

Friending bias

How much less often low-income people make high-income friends than you would expect from how often they meet them. A high value means the chance to mix is there but is not taken.

Social Capital Atlas · Opportunity Insights bias_grp_mem_county

Highest and lowest

Where each measure is highest and lowest among the places reporting both (2023), with the other measure beside it. This is shown for every size of place where both are published. Metro-area values are added up from their counties. A measure that cannot be added up across counties, such as a middle value (median), has no metro figure. Counts are shown per 1,000 residents, since raw totals would only list the largest places. Cities and towns and ZIP codes are shown where the Census survey or the CDC publishes them; most other sources stop at the county. They are shown for places of 5,000 residents or more, and only where the survey’s margin of error is small enough for the figure to be usable. The CDC publishes its health estimates for cities in a version adjusted for age, so places with older or younger people can be compared fairly, but not for ZIP codes.

Counties

By republican swing, 2000 to 2024

Republican swing, 2000 to 2024Friending bias
Highest
Jackson County, TN520.0631
Grundy County, TN50.6-0.0042
Smith County, TN500.0235
Mingo County, WV48.40.00787
Knott County, KY48.20.0526
Lowest
Rockdale County, GA-390.0843
Henry County, GA-33.20.0713
Douglas County, GA-28.70.0718
Teton County, WY-25.50.143
Ouray County, CO-25.3-0.0276

By friending bias

Republican swing, 2000 to 2024Friending bias
Highest
Todd County, SD-8.450.335
Nantucket County, MA-4.890.33
DeSoto County, FL15.40.308
Corson County, SD2.640.273
Marin County, CA-13.40.271
Lowest
Clark County, KS11-0.108
Glascock County, GA16.6-0.106
Armstrong County, TX9.4-0.0962
Oldham County, TX7.14-0.0928
Cleveland County, AR30-0.0816
Metro areas

By republican swing, 2000 to 2024

Republican swing, 2000 to 2024Friending bias
Highest
Pikeville, KY41.60.0161
Scottsboro, AL37.70.036
McMinnville, TN35.40.123
Rio Grande City-Roma, TX350.00257
Lewisburg, TN340.0782
Lowest
Jackson, WY-ID-25.10.0955
Los Alamos, NM-23.20.022
Boulder, CO-20.70.118
Austin-Round Rock-San Marcos, TX-20.60.119
Lawrence, KS-17.60.0445

By friending bias

Republican swing, 2000 to 2024Friending bias
Highest
Nantucket, MA-4.890.33
Arcadia, FL15.40.308
Trenton-Princeton, NJ-3.210.241
Napa, CA-10.30.222
Bridgeport-Stamford-Danbury, CT-4.730.219
Lowest
Harrison, AR17-0.0249
Urban Honolulu, HI-3.07-0.0207
Cullman, AL24.3-0.0194
Rexburg, ID-5.3-0.0125
Moscow, ID-4.91-0.0123

Counties furthest from the pattern

Compared with the straight line that best fits all 2,985 counties: the five with far more friending bias than their republican swing, 2000 to 2024 would suggest, and the five with far less.

Republican swing, 2000 to 2024Friending bias
Above the line
DeSoto County, FL15.40.308
Nantucket County, MA-4.890.33
Todd County, SD-8.450.335
Corson County, SD2.640.273
Jerome County, ID1.070.257
Below the line
Clark County, KS11-0.108
Glascock County, GA16.6-0.106
Armstrong County, TX9.4-0.0962
Oldham County, TX7.14-0.0928
Perkins County, NE3.94-0.0809

Two series, one county

Both measures over time for a county you pick. The two charts are stacked, so they share only the years along the bottom. You can pick from the thirty largest counties reporting both. This panel covers 2010–2024, and a measure published only once shows as a single dot.

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Every version of the link

Each row measures the same link, from −1 to +1, in a different way. If the rows mostly agree, the link does not depend on one choice of method.

Before adjusting for anything-0.2922,978 counties reporting both
After adjusting for density, income and education-0.322the part of the link that is not just how urban, rich and educated a place is
Also adjusting for population size-0.273size taken out as well as density
Also comparing only within each state-0.247each county is compared only with others in its own state, so this is no longer a comparison between states
Giving bigger counties more weight-0.101the adjusted link for the average resident rather than the average county. With this weighting, the data counts for about 285 equally weighted counties
Middle value inside single states-0.253the link worked out inside each of 39 states with at least 20 counties reporting
Using ranks, after adjusting-0.304uses each county’s rank, not its value, so a few extreme counties cannot create the link

How much to believe it

Could it be chance?

The p-value is the chance of seeing a link this strong if there were really none. A value of 0.05 or less means the link is unlikely to be chance. Very small values are written in short form: 3.1e-16 means 0.00000000000000031, and the bigger the number after “e-”, the smaller the value. Treating every county as a separate case gives p = 6.1e-73. But counties in the same state tend to resemble each other, so the better figure allows for that: p = 9.4e-12. The site tested 20,910 pairs, and testing so many turns up some flukes. The q-value allows for that too. For this pair it is 4.1e-72.

Do nearby places look alike?

Moran’s I measures how much nearby places look alike: 0 means no map pattern, and higher means neighbours are more similar. For the part of each county that the adjustment leaves unexplained, it is +0.18 (p = 0.001). That unexplained part still clusters on the map. So some regional factor shared by both measures is not accounted for.

Did they change together?

Not measurable: at least one of these is published for too few of the years a change needs (2014–2019 or 2019–2023), or for too few counties in both.

Related pairs

Association only. Nothing here shows that either measure changes the other. This describes counties, not the people in them. Two measures going together across places does not mean the same people have both. How the US county data works · Explore Republican swing, 2000 to 2024 and Friending bias