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Voter File Data

Learn more about how Voter File Data is collected and processed.

Overview

Voter file records contain the information from the voter registration form, as well as whether someone voted in a given election. Voter file records do not indicate whom an individual voted for. Voter file data is collected and maintained by individual counties. Since the Help America Vote Act of 2002, all states have been required to maintain a computerized statewide voter file. More information here. States have different rules regarding who can access these files and for what purposes they can be used.

Raw voter file data is collected and maintained by individual counties. Commercial vendors purchase, merge, and clean these data, then append numerous other variables gleaned from public and commercial sources. Commercial voter files are regularly used by candidates, parties, interest groups, and other organizations for campaigning and outreach.

Why this is important

Voter file data is useful for understanding the population of eligible voters, and is sometimes used for racially polarized voting analyses. It may also be used in analyses of partisan gerrymandering.

Who is included?

The raw voter files contain anyone in the citizen voting age population (CVAP) who has registered to vote. Only North Dakota does not require citizens to register to vote. In addition, most states have some restrictions against felons voting. See page 5 of this PDF from The Sentencing Project for a chart summarizing state felony disenfranchisement restrictions in 2020.

When is data collected?

Data is collected whenever a citizen registers to vote in person or online, and then updated after each election to reflect whether or not an individual voted and (sometimes) the method by which they cast their vote. Similarly, commercial vendors continuously update their files.

What information is collected?

The information collected varies by state. Typically a voter file will contain a voter’s name, address, and voting history, but it may also contain other information, including but not limited to emails, phone numbers, racial identification, and partisan identification. National Conference of State Legislatures (NCSL) breaks this down state by state. Commercial voter files include all of the previous information, plus up to hundreds more fields with known and predicted attitudes and behaviors.

How is this data collected?

All states (except North Dakota) allow voter registration by mail or in person. Since the National Voter Registration Act of 1993, all states offer the opportunity to register to vote when applying for or renewing a driver’s license. Increasingly, states allow voters to register and vote at the same time. More on same day registration at NCSL.

Raw voter file data is collected and maintained by individual counties. Commercial vendors purchase these data, then append numerous other variables gleaned from public and commercial sources.

How is this data processed?

States may clean, or “purge” voter rolls by dropping voters who fail to meet certain requirements (e.g., by not responding to notices, or not voting in the last few elections). They also use the Postal Service change of address service and audit death records, among other data sources, to maintain accuracy.

Commercial vendors acquire these data, standardize the field names, and merge it with other information from public records and other outside sources, such as credit bureaus and consumer data. As a result of these outside sources, commercial voter file data may also include non-registered voters. These files often contain predictions about the attitudes and behaviors of the individual, based on proprietary models.

Where can this data be found?

Raw voter files can be obtained from county Boards of Elections or similar offices, or the state. Commercial voter file data is available for purchase from a handful of organizations, such as L2 and others.