LAUSR

This article studies invalid voting, which has received very little attention so far, given the broad interest and substantial relevance of voting behaviour research. Existing evidence is mostly limited to rather specific and hardly representative countries. Yet, the extent of invalid ballots is not negligible. Despite undemanding electoral rules, more invalid votes are cast in German general elections than votes for niche parties. Against this backdrop, the article describes prevalence of invalid voting in the mixed electoral system of Germany and tests explanations of its variation between constituencies. Analysing data from the most recent Bundestag Election, results give clear support to politico-institutional explanations: voters are more willing to waste their vote if second-order elections are held concurrently. Specifically under the plurality rule, more (first) votes are wasted if there are large shares for parties without direct candidates and many competing candidates.