Voter file

A voter file is the list of registered voters maintained by state or local election officials, containing each voter's name, address, registration status, and, depending on the jurisdiction, a record of which past elections they voted in. Turnout history is public in many places; ballot choice is never part of the record, since votes are secret. Commercial and campaign vendors license these files, append additional data such as modeled demographics, consumer records, or contact information, and resell enhanced versions to campaigns, parties, advocacy groups, and researchers across the political spectrum.

The voter file is the base dataset behind most campaign analytics: it is the input to turnout modeling, which predicts how likely someone is to vote, and to persuasion modeling, which predicts how movable their views are, and it underlies microtargeting and Get-out-the-vote (GOTV) analytics programs built on top of those models. This differs from a poll sample, which is a small set of respondents interviewed directly; the voter file instead covers the entire registered electorate and is used to target contact, not to ask questions.

Access rules, included fields, and update frequency vary significantly by state, and files can contain errors, such as outdated addresses, duplicate records, or lag in processing new registrations, that analysts need to account for. Because it contains real names and addresses, its use raises ongoing privacy and security questions regardless of which organization is doing the targeting.