DOI: 10.3886/icpsr38506
title: National Neighborhood Data Archive (NaNDA): Voter Registration, Turnout, and Partisanship by County, United States, 2004-2022
title: Archival Version

description: This dataset contains counts of voter registration and voter turnout for all counties in the United States for the years 2004-2022. It also contains measures of each county's Democratic and Republican partisanship, including six-year longitudinal partisan indices for 2006-2022.
description: This dataset was created to explore the relationship between voter engagement (as expressed through registration and turnout rates), partisan political leanings, community health, and public policy.
description: <strong>Voter Registration and Turnout</strong>


To construct measures of voter registration and turnout, researchers calculated three figures for each county in the United States:

Registered voters: the total number of people registered to vote in the county
Ballots cast: the total number of votes cast in the November general election for each year
Voting population: researchers evaluated three possible measures for this component and selected Citizen Voting Age Population (CVAP), which excludes noncitizens



Researchers then calculated three ratios using these components:

Voter registration: registered voters / voting population
Voter turnout: ballots cast / voting population
Registered voter turnout: ballots cast / registered voters



<strong>Partisanship</strong>


For the years 2006-2022, researchers calculated Democratic and Republican partisanship indices for each county based on its voting history in presidential and Senate races over the current and three prior elections. Researchers built this index based on votes for president and senator because these races occur consistently in even years in all fifty U.S. states.


Researchers extracted votes for Democratic and Republican presidential candidates from county-level data on presidential election outcomes for the years 2000-2022. For Senate races, researchers summarized 2000-2022 precinct-level votes for Democratic and Republican candidates to the county level, then joined them with the presidential election vote counts. This resulted in four figures per county per year:

PRES_DEM_VOTES: Votes for Democratic presidential candidates
PRES_REP_VOTES: Votes for Republican presidential candidates
SEN_DEM_VOTES: Votes for Democratic Senate candidates
SEN_REP_VOTES: Votes for Republican Senate candidates



For each county and year, researchers created four ratios:

PRES_DEM_RATIO: PRES_DEM_VOTES / (PRES_DEM_VOTES + PRES_REP_VOTES)
PRES_REP_RATIO: PRES_REP_VOTES / (PRES_DEM_VOTES + PRES_REP_VOTES)
SEN_DEM_RATIO: SEN_DEM_VOTES / (SEN_DEM_VOTES + SEN_REP_VOTES)
SEN_REP_RATIO: SEN_REP_VOTES / (SEN_DEM_VOTES + SEN_REP_VOTES)



Researchers then calculated annual Democratic and Republican partisanship indices and six-year aggregate Democratic and Republican partisanship indices for each county for 2006 through 2022. The Democratic index is the average of the presidential and Senate Democratic vote ratios over the current and previous four elections. The Republican index is calculated using Republican vote ratios in the same manner. The two indices add up to one for each county and year.


For greater details regarding this process, users should consult the accompanying documentation.
description: Datasets: 
DS1: National Neighborhood Data Archive (NaNDA): Voter Registration, Turnout, and Partisanship by County, United States, 2004-2022
description: Counties in the United States, excluding Alaska and island territories. Smallest Geographic Unit: County Federal Information Processing System (FIPS)
description: record abstractsThe initial release version of these data and documentation (years 2004-2018, version 1) were originally deposited in openICPSR 125781.For additional information, see
the National Neighborhood Data Archive (NaNDA).