Transaction costs in electoral coordination: How turnout shapes changes in the number of parties*

This article examines the forces shaping changes in the number of parties between consecutive elections. We argue that the transaction costs in electoral coordination depend on the turnout level in the previous election. The greater the number of peripheral voters entering the electorate, the less likely a substantial change in the distribution of partisan support in the subsequent election. The argument is tested using data for 313 parliamentary elections in 63 countries from 1990 to 2011, and two cases studies of countries using compulsory voting (the Netherlands and Australia).