Dettman, S., Pepinsky, T.B. and J.H. Pierskalla (2017) “Incumbency advantage and candidate characteristics in open-list proportional representation systems: Evidence from Indonesia”. In Electoral Studies 48. DOI:


Do incumbents profit from an electoral bonus in developing democracies, where voters tend to have little information to judge the quality of candidates? While some recent studies indicate that voters might punish rather than reward office-holders in developing democracies (see e.g. Klašnja and Titiunik 2017; Uppal 2009), Dettman et al. turn the common wisdom back on its feed in their recent publication. The authors investigate the effects of incumbency on list placements, preferential votes, and electoral success of candidates in Indonesia’s open-list proportional electoral system. For that purpose, they use an original data set covering all candidates running at the 2014 lower house elections. It includes information about list placement and vote shares, but also attributes such as religion, gender, or professional background. The analyses show that incumbency increases electoral success through two mechanisms: Firstly, candidates holding legislative office carry more weight in the intra-party competition for promising list placements and voters tend to give their preferential votes to candidates with high rankings on party lists. Secondly, incumbents can cultivate a personal vote and build a reputation independent from their party – a factor advantageous in the struggle for preferential votes between candidates belonging to the same party.



This study contributes to the literature by disentangling the effects of expected electoral success, list placement, and actual vote shares. Nevertheless, a close look at the findings indicates that the incumbency advantage works only within narrow confines. To begin with, only the office-holders who secured the most promising list positions might have an electoral bonus. The authors mention that the positive effect of incumbency on preferential votes diminishes as the list ranking decreases (p. 118). While indeed most office-holders running for re-election are ranked on the first two places of the party lists (Dettman et al. 2017, 115), still about 20% of them are placed on the third position or below so that they do not profit from the electoral bonus. In addition, only a subset of voters might make use of incumbency as a clue for candidate quality. The preferential vote is not obligatory in the Indonesian electoral system and the exact share of voters using this tool remains unfortunately unknown to the reader. We do, however, learn that the average winning candidate receives a mere 5.45% of the district votes (Dettman et al. 2017, 115), which suggests that only a small group of voters cast preferential votes and incorporates the incumbency status as clue for candidate quality into the voting decision.[1] The remaining part of the electorate – which is arguably less well-informed given that it wastes its chance to influence the candidate ranking – might judge based on very different grounds.


Author: Corinna Kroeber in July 2017


[1] While seats are allocated to parties based on party vote shares using a largest remainder quota, seats are distributed among party candidates based on simple pluralities of preferential votes. The district magnitude ranges between 3 and 10 seats per district.


Klašnja, Marko; Titiunik Rocío (2017) “The incumbency curse: weak parties, term limits, and unfulfilled accountability”, in American Political Science Review 111 (1): 129-148.


Uppal, Yogesh (2009) “The disadvantaged incumbents: estimating incumbency effects in Indian state legislatures”, in Public Choice 138 (1): 9-27.


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