Popularity equilibrium: testing a general theory of local campaign efficacy

Parties and candidates target campaign resources where they are most likely to pay electoral dividends. At the individual level it has been shown that some individuals are more likely to be persuaded by campaign contacts than others. In a parallel tradition of measuring campaign effectiveness at the macro level, previous research has demonstrated that local candidate campaign effort measured is significantly related to electoral performance. However, while there is evidence suggestive of macro level effects, there is little systematic evidence about the district level conditions under which campaign efforts are most productive. Drawing on extensive data across six UK general elections between 1992 and 2015, we advance a theory of local campaign efficacy and test a general model of popularity equilibrium. We demonstrate that there is a
curvilinear relationship between the underlying level of party support in an electoral district and the intensity of the district level campaign – there is a ‘sweet-spot’ for maximizing the returns of campaign effort.