Strategic Choices in Election Campaigns: Measuring the Vice-Presidential Home State Advantage with Synthetic Controls

Abstract

Measuring the effect strategic choices have on electoral outcomes is problematic, since this requires an assessment of the outcome under a counterfactual that is not observed. To overcome this problem we extend the synthetic control approach for causal inference to circumstances with multiple treated cases, and use it to estimate the effect of vice-presidential candidates on their home states' vote. Existing research has concluded that vice-presidential candidates have little effect on the outcome of elections in their home states. However, our results from elections spanning 1884-2012 suggest that vice-presidential candidates increase their tickets' performance in their home states by 2.67 percentage points on average - considerably higher than previous studies have found. Additionally, our results suggest that the vice-presidential HSA could have swung four presidential elections since 1960, if presidential candidates had chosen running mates from strategically optimal states.