What is the voting-age population (VAP) and the voting-eligible population (VEP)?
The voting-age population, known by the acronym VAP, is defined by the Bureau of the Census as everyone residing in the United States, age 18 and older. Before 1971, the voting-age population was age 21 and older for most states.
The voting-eligible population or VEP is a phrase I coined to describe the population that is eligible to vote. Counted among the voting-age population are persons who are ineligible to vote, such as non-citizens, felons (depending on state law), and mentally incapacitated persons. Not counted are persons in the military or civilians living overseas.
The voting-age population is appropriately adjusted in order to arrive at the voting-eligible population, as described in this FAQ. For maximum transparency, the voting-age population estimates and statistics used to modify it to arrive at the voting-eligible population are provided along side the turnout rates.