Federal Primary Election Runoffs and Voter Turnout Decline, 1994-2008
Updated: March 2009

This study focuses on voter turnout in federal primary and primary runoff elections, looking at the eight primaries for major party nominations for U.S. House and U.S. Senate held between 1994-2008.

The study also looks at comebacks, or elections in which the runoff winner had trailed in the first round primary, and incumbency. In addition, we have information on differences in turnout based on candidates’ race and gender.

Summary of Findings:

Turnout overall: Of 116 total federal election runoffs for the period under study, 113 – all but three – saw turnout declines. The mean turnout decline for the period was 35.11%. The median decline was 32.85%.

Largest turnout decrease and lowest turnout: The largest decrease in turnout took place in the 2008 Democratic runoff for U.S House in Texas' 32nd district, which saw a 93.88% decline in turnout from the primary to the runoff election. The lowest turnout in a runoff was also in Texas, in the 2006 Republican runoff for the 30th U.S. House district, where only 1,856 voters showed up at the polls.

Turnout election by election: Turnout dropoff numbers have been similar over the years, with a slight trend upwards. Here is the mean turnout decline in each election in our period of study:

2008: 38.39%
2006: 43.31%
2004: 38.96%
2002: 30.20%
2000: 47.96%
1998: 31.62%
1996: 35.56%
1994: 28.10%

U.S. House vs. U.S. Senate: 39.38% dropoff in Senate runoffs. 34.45% dropoff in House runoffs.

By party: 36.16% dropoff in Democrat primary runoffs. 34.44% dropoff in Republican primary runoffs.

Gender: 38.75% dropoff in runoffs for female candidates.

Race: 30.98% dropoff in runoffs for candidates of color (note the sample is incomplete).

Comebacks: 29.31% of candidates trailed in the first round but won the runoff (34 candidates).

Won general: 42.24% of candidates involved in runoffs went on to win the general election (49 candidates).

Note: 2008 Louisiana general election primaries and primary runoffs were not included in the data, as the primary date was postponed until the general election date, due to Hurricane Gustav, making this an unusual situation where runoff turnout was inflated by voters coming out to vote in the presidential election.

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