Pastine, I., Pastine, T., Redmond, P., 2015. Incumbent-quality advantage and counterfactual electoral stagnation in the U.S. Senate. Politics, 35(1), 32-45.

This article examines the extent to which electoral selection based on candidate quality alone can account for the pattern of re-election rates in the US Senate. In the absence of officeholder benefits, electoral selection is simulated using observed dropout rates from 1946 to 2010. This provides a benchmark for the re-election rate that would be generated by incumbent quality advantage alone. The simulation delivers a re-election rate that is almost identical to the observed rate prior to 1980, at around 78 per cent. In the later subsample, quality-based selection generates a re-election rate that is seven percentage points lower than observed. The divergence in the re-election rates in the later subsample is consistent with the findings of vote margin studies that indicate rising incumbency advantage due to officeholder benefits. In addition, it is found here that the quality-based selection first-term re-election rate is significantly lower than the observed first-term re election rate. This result supports sophomore surge vote margin studies of officeholder benefits.

Redmond, P., Regan, J., 2015. Incumbency advantage in a proportional electoral system: a regression discontinuity analysis of Irish elections. European Journal of Political Economy, 38: 244-256.

The existence of a large incumbency advantage in the winner-takes-all plurality system of the United States is well documented. It is unclear whether incumbents in proportional systems should enjoy such a large advantage. Multi-seat constituencies make it difficult for individual incumbents to claim credit for the provision of local public goods and services. Moreover, multiple incumbents may dilute media attention thereby limiting name recognition advantage. We use a regression discontinuity design to estimate the causal effect of incumbency using election data from Ireland’s system of proportional representation with a single transferable vote (PR-STV). Incumbency causes an eighteen percentage point increase in a candidate’s probability of winning a seat in the next election. Our results indicate that the protection of vulnerable incumbents from intra-party competition may be an important source of incumbency advantage in multi-member district elections.

Working Papers

Redmond, P. Incumbent-Challenger and Open-Seat Elections in a Spatial Model of Political Competition


I compare the outcomes of incumbent-challenger and open-seat elections in a model of spatial electoral competition. Candidates are policy motivated and may differ in their non-policy attributes which are collectively referred to as valence characteristics. Candidates adopt more divergent policies in the incumbent-challenger election compared to an open-seat contest and the divergence is higher when the incumbent is at a valence disadvantage. Policy motivated incumbents benefit from an incumbency advantage in being able to choose their policy before the challenger.