The Campaign Value of Incumbency: A New Solution to the Puzzle of Less Effective Incumbent Spending


  • We thank Matthew Kerby and Liam Weeks for assistance in preparing the dataset and Thomas Däubler for comments. A full replication dataset will be available from the authors upon publication of this article. This is one of several joint papers on campaign finance by the authors, and the ordering of their names reflects alphabetic convention. Kenneth Benoit thanks the Irish Research Council for Humanities and the Social Sciences for support in 2006–2007.

Kenneth Benoit is professor of quantitative social sciences, Trinity College, Dublin 2, Ireland ( Michael Marsh is professor of comparative political behaviour, Trinity College, Dublin 2, Ireland (


A puzzle in research on campaign spending is that while expenditure is positively related to votes won, this effect is far more strongly, or even exclusively, enjoyed by challengers rather than by incumbents. We unearth a new explanation for the puzzle, focusing on the hidden, yet variable, campaign value of office perquisites which incumbents deploy in their campaigns to win votes. When these variable office benefits are unobserved, then the effect is to make observed incumbent spending less effective than spending by challengers. Using data from the 2002 Irish general election, where incumbency was assigned a variable campaign value and included in declared campaign spending, we are able to demonstrate this hidden incumbency effect and estimate its relationship to electoral success, in terms of overall votes, share of votes, and probability of winning a seat. Contrary to previous research showing ineffective incumbent spending, we find that when the campaign value of office is also measured, public office value “spending” is not only very effective in winning votes, but also seems to be more effective than regular incumbent spending.