Replication data for: A New Approach to Estimating Electoral Instability in Parties

Recent scholarship has identified problems in the measurement of party system instability. To limit the conflation of different sources of instability in party systems (e.g., electoral shifts between stable parties and instability in parties, such as mergers, splinters or new parties), this article introduces a new indicator of electoral instability in parties, tests its robustness and construct validity and demonstrates its usefulness empirically. The indicators of party instability and the accompanying data of twenty-seven European democracies, 1987-2011, will be valuable resources in comparative research on the interplay between elite and mass behavior, party and electoral systems and democratic consolidation.