A Correlation Between State Competitiveness and Voter Turnout?

As we wind down 2016 and start up 2017, more of our Decision Desk volunteers will be blogging on various odds and ends. Today, Alexander Agadjanian, who worked with us in Hanover, New Hampshire, joins us. You can follow him on Twitter at @A_agadjanian.

The Electoral College has undoubtedly proven a focal point of post-election discussion. With Hillary Clinton becoming only the fourth presidential candidate in history to win the popular vote but lose the Electoral College, the debate has turned partisan and centered on whether the system for deciding the election should exist in the first place.

In a sense, the discord regarding this electoral institution also coincides with another longstanding normative question—whether the Electoral College discourages greater participation in the voting process. Because the Electoral College doles out state-level rewards based on reaching a plurality threshold of support, Americans living in very blue- or red-leaning states understandably could plausibly think their vote has little influence compared to Americans living in more competitive swing states. Perhaps this could explain the dispiriting voter turnout in this country that sees only about three in five eligible Americans turn out to vote.

The alternative of the national popular vote deciding the election winner would supposedly motivate many more people to vote, as all votes in the country would matter equally regardless of state-level differences in competition. This would more or less approximate the level of motivation citizens in competitive states experience under an Electoral College system, only now that motivation would drive all citizens in a popular vote system.

While I can’t predict what would happen with voter participation levels in a popular vote system, I can examine the following: whether voter turnout varies by level of state competition, and thus whether motivation stemming from a more competitive electoral environment actually correlates with greater turnout. I first examine this idea for the 2016 election. I use state turnout measures from the U.S. Election Project website. Among the different turnout rates listed, I use the Voting Eligible Population (VEP) Highest Office rate—the presidency in 2016—as this appears for every state (unlike the Total Ballots Counted rate). I get state voting from the U.S. Election Atlas, and define competitiveness as how close the margin between the two major party candidates—Hillary Clinton and Donald Trump—is by taking the absolute value of their difference in percentage support:

Competitiveness = | (Clinton vote % – Trump vote %) |

In the below graph, I plot state competitiveness on the x-axis against state turnout on the y-axis:

Absolute Difference in Clinton-Trump Support

Although not extremely correlated, there is clear moderately strong relationship between state competitiveness and turnout in the 2016 election. In states that were decided by closer margins and thus were more competitive, turnout typically proved higher. I overlay a smoothed linear model to capture the negative association between difference in candidate margins and turnout—as margins decrease (get closer), turnout increases. States like Michigan, Florida, and North Carolina, which were closely contested and had fairly high turnout, fall right on this line. But again, the relationship is far from perfect.

To gauge how common this pattern has been in recent elections, I plotted the same variables over the last five cycles. That’s what the below grids illustrate, along with correlation coefficients—numerically capturing the relationship—between these two measures for each election year appearing in red:

Turnout in Last Five Cycles

It appears that the strength between competitiveness and turnout only began to materialize in the last few elections. In the 2000 election, for example, there was essentially no relationship (correlation of -0.02) between how close a state was and voter turnout. The association grew a bit in 2004, which saw a -0.24 correlation between the two variables, and in 2008 with a -0.28. However, it’s been the 2012 election (-0.51 correlation) and the 2016 election (-0.52 correlation) in which competitiveness and turnout have become much more tightly linked.

This is of course bivariate analysis that leaves out plenty of other factors that could influence turnout, but there seems to be some credence to the aforementioned theory: close battleground states generally produce higher turnout among their eligible citizens, while staunchly Democratic or Republican states see their citizens abstain from elections more often.

There’s a chance this analysis would make more sense by incorporating a lag for state competitiveness. In other words, it could seem more theoretically sound that voters would view closeness in their state’s previous election, and on that account decide whether to participate in the upcoming election. I tested this possibility (e.g. connection between 2016 turnout and 2012 competitiveness at the state level), but found the relationship was generally weaker than when comparing the variables within the same election year.

As I mentioned before, this simple analysis omits other potentially meaningful factors. One factor that could prove informative—and especially for the changes in correlative power over time described above—is campaign resource allocation, and “get out the vote” (GOVT) efforts more specifically. Political science field experiments, the most seminal of which published in a 2000 paper, helped popularize new ways of contacting and mobilizing citizens. Personal canvassing in particular significantly increased turnout, and the broader implementation of smarter GOVT methods gained traction in the last few elections.

These better GOTV efforts would reap the most rewards in more closely contested states, and thus turnout efforts likely concentrate in battleground parts of the country. In a FiveThirtyEight article, Joshua Darr confirmed this allocation of campaign resources—through the proxy of number of campaign field offices—that centers heavily in battleground states during the 2012 and 2016 elections. This could all mean that GOTV campaign efforts better explain variation in state turnout than perceived state competitiveness does. Accordingly, over Twitter, I was also pointed to a paper that showed an increasing effect of campaign efforts on turnout over the elections since 1996—which squares with the increasing relationship between state competitiveness and turnout I showed earlier.