Why is New Hampshire More Competitive than Pennsylvania? Historical Electoral Competitiveness and Swing State Selection

The electoral competitiveness of a geographic area, such as a US state, is usually measured as the deviation of the ex post election outcome from a tie, which assumes campaigns have perfect foresight expectations about the outcome, ignores prior election results, and does not account for over-time variation within a state. This paper introduces a measure of historical estimated electoral competitiveness that incorporates past election results and over-time volatility. The measure explains presidential campaigns’ advertising spending in 2008 and 2012 better than other frequently-used measures. Results from elections four decades past exert a significant effect on campaign expenditures in the 2008 and 2012 elections. The 1976 election appears particularly influential in recent campaign spending patterns. Historical estimated competitiveness shows that Romney’s campaign overspent in New Hampshire and Wisconsin in 2012, and both campaigns underspent in Ohio in 2008 and 2012.