We have created some guides for earlier datasets to help explain the use of these variables in a bit more detail. In more recent years, this information has been integrated into the guides themselves. We recommend you consult these guides as the validation process and variables change slightly from year to year. However, some brief information follows.
Typically, the main variable of interest will be the variable indicating the vote method used by a respondent. This typically takes on values such as “absentee,” “mail,” “early,” “polling,” and “unknown.” If a respondent has any of these values, they have a validated vote record (“unknown” means that the state did not record what method the individual used to vote, but the individual did vote).
It should be noted that a record may not be matched to the voter file either because the individual is not registered to vote or because of incomplete or inaccurate information that prevented a match. Matches are made only with records for which there is a high level of confidence that the respondent is being assigned to the correct record. However, even by setting a high threshold of confidence, there will still be some false-positives which should be considered when using the validation records.
For identifying non-voters, the researcher may take several different approaches. These different options are laid out in the guides, but the most common approach is to simply treat all individuals who are not validated voters as non-voters (regardless of whether they were matched to the voter files or not). The justification for this approach is the fact that the most common reason that the voter file firm will not have a record for an individual is because that individual is not registered to vote. Indeed, rates of self-reported non-registration and non-voting are much higher among un-matched respondents than among those for whom there is a match.