Why bother campaigning? Campaign effectiveness in the 2009 European Parliament elections

•We study the effectiveness of candidate spending in the 2009 European Parliament campaign.•Ceteris paribus, spending is positively related to a candidate's likelihood of electoral success.•Electoral expenditure effects are relatively small in scale.•We investigate whether spending effects are conditioned by ballot structure and incumbency.•There is no evidence of ballot structure conditioning, and some evidence for incumbency conditioning.

This paper explores the effectiveness of European Parliament candidates' campaigns. We analyze the relationship between candidates' spending and their likelihood of success, controlling for a range of relevant co-varying factors. We then investigate whether the effects of electoral spending are conditioned by two variables: ballot design and incumbency. We find that, ceteris paribus, spending was positively related to a candidate's likelihood of electoral success in the 2009 campaign, though this effect is small in scale. We also reveal that the electorally positive effects of spending are observable across both 'party-centered' and ‘candidate-centered’ ballot structures, and that there is some evidence that incumbent spending is less effective than challenger spending.