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
using 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 maximising the returns of
campaign effort.