FairVote has compiled and analyzed state-by-state data on voter turnout for the 2016 presidential primaries. Released today, it reviews trends in voter turnout nationally since 2000, as well as differences in turnout by party. Also included is a deeper analysis of the 23 states which held competitive primaries in both 2008 and 2016, exploring the effects of primary type (open, closed, or hybrid) and voter access laws. A full report can be downloaded from FairVote’s website.

Record Breaking Republican Turnout; Decreases in Democratic Turnout

Wisconsin experienced increased participation by more than 10% compared to the 2008 primary elections. In Wisconsin, 49% of eligible voters participated in the primaries, the second highest in the nation behind only New Hampshire, where 52% participated in the nation’s first-in-the-nation primary. Primary participation was lowest in Louisiana (18.2%), South Dakota (18.9%), New Jersey (21.0%), and Connecticut (21.0%).

Spotlight on Competitive Nomination Contests

• Overall Turnout in Competitive Primary States Flat: Turnout in states with competitive primaries for both parties in both 2008 and 2016 was 31% in both 2016 and 2008.

• Republican Turnout Rises, Democratic Turnout Declines: While turnout in competitive primary states did not change, turnout within the two major parties’ primary contests diverged. Across the states, Republican participation increased 51% (from 11% to 16% of the eligible population), and Democratic participation decreased 23% (from 19% to 15% of the eligible population). The record-breaking participation seen in 2008 for the Democratic nominee, then-Senator Barack Obama, likely contributed to the relative decline among Democratic turnout in this year’s contest.

• Open Primaries Affect Republican and Democratic Turnout: The mean increase in Republican turnout among open primary states was 68% up from 11% to 19% of the voting eligible population. In closed primary states, however, the mean increase among Republicans was only 29%, up from 9% to 11% of the voting eligible population. The mean decrease in Democratic turnout among open primary states was 31%, as turnout dropped from 21% to 15% of the voting eligible population. Among closed primary states, the mean decrease among Democrats was only 11%, down from 15% to 13% of the voting eligible population. These factors, combined with unchanged overall turnout, provides evidence of party switching and new voter participation.

Turnout Decreased the Most in Open Democratic Primaries

A comparison of the mean increases and decreases in turnout between open primary states, closed primary states, and hybrid voting states (Figure 7, below) reveals stark differences between parties, particularly in open primary states. The patterns suggest that the near universal increase in participation in the Republican contests is likely a combination of new voters who skipped the 2008 contest, in addition to an increase in the number of independents and Democrats who chose to cast Republican ballots in open primary states.

In the average closed primary state (determined by taking the mean of the increases in participation in all closed primary states included in this sample), Republican turnout increased by about 29%. In the seven closed primary states we examined, Republican turnout increased even in states like Arizona and Florida, where statewide primary participation fell.

In closed primary states, there are a variety of restrictions on who is allowed to participate. Many states have very early party-change deadlines, for example, meaning voters must switch their party affiliation months before the election if they intend to participate in that party’s primary. Independents and unaffiliated voters are barred completely from casting ballots in closed primary contests. Because of these restrictions, turnout changes in closed primary states are likely due in large part to different proportions of party voters turning out rather than party switching or independent voters.

The increase in Republican turnout in these states indicates that voters who did not participate in the 2008 contests are turning out in 2016. Some are new voters, participating in their first primary; others are voters who voted Republican in the past, but stayed at home in 2008. Because unaffiliated and Democratic voters do not have access to Republican ballots in closed primaries, and the process of changing party affiliation often requires a good deal of planning and effort, the increase in Republican turnout in closed primary states is unlikely to be largely due to en masse party switching or unaffiliated voters affiliating, although there have beenefforts encouraging people to “ditch and switch”. In Pennsylvania, for example, only an estimated 200,000 voters switched9 parties, representing about 2.5% of the 8,273,703 registered voters10 in that state.

Party Switching in Republican Contests

Overall turnout in open primary states was relatively constant from 2008 to 2016: turnout rose slightly from 32% to 34% in open primary states and stayed static in closed primary states at 24%. But this apparent static turnout obscures significant changes in Republican turnout, with Republican turnout rising more in open primary states, from 11% to 19%, on average. Many of these new voters might include long-time Republicans who were newly inspired to vote in 2016, but if that were the case, we would have expected similar increases in closed primary states. In closed primary states, however, Republican turnout only increased from 9% to 11%, on average.

Who, then, are the other voters contributing to the heightened levels of participation in Republican primaries in open primary states this year? Turnout increases in Republican primaries in open primary states are likely the result of not just of an influx of new voters, but also regular independent and Democratic voters who switched over to participate in the Republican contest this year. The possibility of party switching is most clearly demonstrated in the open primary states with very small changes in turnout but large changes in Republican turnout.

In South Carolina, for example, turnout did not meaningfully change compared to 2008, while Republican turnout increased 47% and Democratic turnout decreased 39%. In 2016, the reduction in Democratic turnout in South Carolina was almost twice the national mean (23%) and national median (25%), suggesting that the drop in turnout is not entirely explained by the expected decrease in Democrats participating in the Democratic primary following Obama’s historic 2008 campaign. In 2016, South Carolina Democrats had good reason to turn out: the state voted immediately after Iowa and New Hampshire, when neither Hillary Clinton nor Bernie Sanders could claim a commanding delegate lead. After Clinton narrowly won Iowa and Sanders won by a landslide in New Hampshire, each candidate looked to solidify their momentum in South Carolina and Nevada.

In 2008, South Carolina was in a similar position, facing a high stakes choice between Obama and Clinton and a last chance for the campaign of John Edwards. South Carolina Democrats voted on January 26th, only the fifth state to cast Democratic ballots and, as in 2016, the third sanctioned contest. These comparably competitive positions on the primary calendar in both years make the drop in turnout for 2016 particularly stark in this state.

Simultaneously, South Carolina Republican turnout soared by 47%, almost matching the national mean of 51%. South Carolina’s flat primary turnout, larger than expected decline in Democratic turnout, and significant increase in Republican turnout suggest that some voters who participated in the Democratic primary in 2008 switched to the Republican primary in 2016 and, when combined with voters who sat out for the 2008 Republican contest, slightly drove up Republican participation. South Carolina Republican voters cast a ballot when six candidates, Trump, Kasich, Bush, Carson, Rubio and Cruz remained in the race.

While differences clearly exist between open primary states and closed primary states, other factors are also at work contributing to the steep increase in Republican turnout and a decline in Democratic turnout in 2016. In addition to the type of primary used in a state, legal changes since 2008 may also help explain turnout differences between states and parties.

Editor's note: This article, written by Molly Rockett, originally published on FairVote's blog on July 22, 2016.