Measuring re-election prospects across electoral systems: a general approach applied to Germany

Abstract

This research note presents a general approach for measuring the electoral safety of individual MPs across electoral systems that is based on predicted re-election probabilities estimated from multilevel logistic regression models. In contrast to existing measures, this method yields estimates on an intuitive and readily comparable probability scale, captures the higher sensitivity of re-election prospects to electoral change in the range of close races, and can accommodate regional differences in context conditions such as volatility. The paper implements the approach for two archetypical electoral systems – first-past-the-post (FPTP) systems and closed-list proportional representation (PR) – and estimates re-election prospects for the FPTP and PR tiers of the German mixed electoral system in all Bundestag elections since 1957. While the empirical data presented here is mainly illustrative, the concluding section highlights various questions that future research can address with the new measure.