Voting age population

Voting age population (VAP) refers to the set of individuals that have reached the minimum voting age for a particular geographical or political unit. The presumption is that they are therefore generally eligible to vote, although other additional factors may cause them to be ineligible, such as lack of citizenship or a prior felony conviction. In estimating voter turnout the voting age population for a political unit is often used as the denominator for the number of individuals eligible to vote in a given election; this method has been shown to lose in accuracy when a larger percentage of the VAP is ineligible to vote. In the United States individuals become eligible to vote in political elections at age 18.

In the context of voter files used for political organizing, VAP has a slightly different meaning and refers individuals who reside in a geography and who are not currently registered to vote, because under normal circumstances only individuals who are registered to vote would be included in political communications (due to cost efficiency). These VAP records are typically identified by matching a commercial marketing database to state voter registration data and flagging records which are not found to be registered to vote. Political organizations can then use those flags to include or exclude unregistered individuals in target lists for political organizing programs, such as communications that encourage voter registration or voter turnout.

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