What should be the denominator when calculating voter turnout? This is an ongoing discussion, usually with respect to Voting Age Population or Voting Eligible Population, the latter construct developed by my UF colleague, Mike McDonald.

But what should be the denominator when drawing on official voter files?

The Florida Division of Elections has provided two different measures for the 2016 Presidential Preference Primary.

The following is from the FDOS:

As of 3/27/2016 12:00 pm, the voter turnout percentage for the subset of active registered voters statewide eligible to vote in the Presidential Preference Primary race was 46.23%. The subset percentage consists of 4,089,516 votes cast out of the total number of active registered Republicans and Democrats (8,845,892) as of the registration deadline.

This sounds reasonable. The total votes cast by Republicans and Democrats divided by the total number of ACTIVE registered voters registered with the two major parties.

But it’s not really the total turnout in the March 15, 2016 election. Many counties and municipalities had local elections with nonpartisan contests or ballot issues; thousands of registered voters who belong to a third party, or who don’t belong to any party, turned out to vote.

So, FDOS also has offered this turnout figure:

The total voter turnout percentage, including nonpartisan municipal/county level races, was 34.53% (4,164,001) compared against the total number of active registered voters in the state (12,060,748) as of the registration deadline.

That’s a huuuuge difference in turnout.

And turnout rates would be even lower if the denominator included all of Florida’s registrants, including those who have INACTIVE status. FDOS (and the county SOEs) don’t include these legally registered voters in their denominators, even though thousands of them turned out in the election.

I’m not sure what’s the correct way of determining turnout. But it matters with respect to our perception of the level of enthusiasm in the Florida electorate.