Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
County-level data are used to estimate the incumbent-party share of the two-party vote in the 2012 and the 2016 U.S. Presidential elections. Using a ‘seemingly unrelated estimation’ procedure the regression results for the two elections show that there were some clear differences in the size of marginal effects for several key covariates. For example, income inequality, the size of the black male and black female populations, the size of the Hispanic male population and percent of the population with a college degree all had significantly larger coefficients in 2016 than in 2012, producing a larger marginal effect in favour of the Democratic candidate’s vote share. On the other hand, counties with increased poverty rates and counties located on the periphery of urban centres had a significantly larger marginal effect favouring the Republican’s vote share in 2016 compared to 2012. Finally, the regression results show that the effects of third-party vote shares, though not statistically different across the two elections, had a positive impact on the Democratic vote share in both elections.