What Affects Invalid Voting? A Review and Meta-Analysis

Research on invalid voting has expanded rapidly over the past few years. This review article for the first time examines its principal findings and provides a new theoretical perspective on the origins of invalid votes based on a two-dimensional framework. The main results of 54 studies using both individual-level and aggregate-level data as well as the results of experimental and qualitative studies are analysed. The meta-analysis of all existing aggregate-level studies finds that compulsory voting, quality of democracy, fragmentation and closeness of the electoral race play important roles in explaining invalid voting. On the other hand, the research is accompanied by many theoretical and empirical contradictions that hamper the accumulation of knowledge in this field. We therefore conclude by suggesting the challenges for future research.