When Does Money Matter for Elections?

This paper studies electoral campaigns over the long run, through the lens of their spending. In particular, we ask whether changing media technologies and electoral environments have impacted patterns of campaign spending, and their correlation with electoral results. To do so, we build a novel exhaustive dataset on general elections in the United Kingdom from 1857 to 2017, which in­cludes information on campaign spending (itemized by expense categories), electoral outcomes and socio­demographic characteristics for 69,042 election­-constituency­-candidates. We start by providing new insights on the history of British political campaigns, documenting in particular the growing importance of advertising material (including via digital means), to the detriment of paid staff and electoral meetings. Using a saturated fixed effects model, we then show that there is a strong positive correlation between expenditures and votes, and that overall the magnitude of this relationship has strongly increased since the 1880s, peaking in the last quarter of the 20th century. We link these transformations to changes in the conduct of campaigns, and to the introduction of new information technologies. We show in particular that the expansion of local radio and broadband Internet increased the sensitivity of the electoral results to differences in campaign spending.