Prior to the November general election, many wondered how negative feelings towards both presidential candidates would impact other races on the ballot, since voters in a presidential election often go to the polls to cast a ballot for president and then drop-off for other races. Drop-off measures the difference in turnout between the race at the top of the ticket, in this case the presidential race, and races further down the ballot, such as a United States Senate race. Drop-off increases the further down the ballot you go, as voter knowledge of and interest in candidates and offices below the state level decreases.
The average drop-off in states with a Senate race in 2016 was 1.99 percent, compared with 2.36 percent in all states with a Senate race in 2012. Most states saw the drop-off rate change less than one percentage point in either direction between 2016 and either 2012 or 2008, but several states saw much larger changes in the drop-off rate. Arkansas decreased from 6.89 percent in 2008 to 2.04 percent in 2016 (a change of 4.85 percentage points) and Oklahoma decreased from 7.92 percent in 2008 to 0.34 percent in 2016 (a change of 7.58 percentage points); California increased from 3.53 percent in 2012 to 13.66 percent in 2016 (a change of 10.13 percentage points).
So why the big decreases in the drop-off rates in Arkansas and Oklahoma? It’s difficult to say for sure, but we can make an educated guess about Arkansas, at least. In 2008, incumbent Democratic Senator Mark Pryor did not have Republican opposition, suggesting that many Republican voters might have come out for the presidential race and skipped the Senate race. In Oklahoma in 2008, however, incumbent Senator Jim Inhofe had Democratic opposition, so beyond the historic nature of the presidential race, it’s not immediately clear why the drop-off rate would have been so high.
The increase in California’s drop-off rate is eye-popping. Proposition 14, which implemented a top-two primary resulting in a run-off between the top two vote-getters regardless of party, went into effect in 2011, but the 2012 Senate general election was still between a Democrat, Dianne Feinstein, and a Republican, Elizabeth Emken. The 2016 Senate general election, however, was Democrat versus Democrat – Kamala Harris versus Loretta Sanchez. Republican voters had no horse in the Senate race.
In November 2016, Los Angeles County had the lowest drop-off rate (9.3 percent) of all 58 counties in California; in 2012, just two counties had a drop-off rate of greater than or equal to 5 percent – Colusa (5 percent) and San Bernardino (5.2 percent). Of the 15 counties with the lowest drop-off rates in 2016, 14 are majority Democratic, but Orange County, the largest Republican county in the country, had the 15th lowest drop-off rate in the state. 25 California counties had drop-off rates greater than 20 percent in 2016 – including two at or above 30 percent – and all but four of those have more registered Republicans than Democrats.
The drop-off rates in California were, across the board, higher in 2016 than in 2012, and it’s likely that the top-two primary that pitted two Democrats against each other in November played a role in that. But Los Angeles – the largest Democratic county in the country and the county that had the lowest drop-off rate statewide – also saw a large increase in drop-off from 2016 to 2012, making it possible that other issues such as unhappiness with the candidates themselves, lack of knowledge about the candidates, or something else entirely, played a role as well.