The Comparative Study of Electoral Systems (CSES) is a collaborative, cross-national program of comparative electoral behavior among over 60 election study teams from around the world. The CSES allows examination into how societal, political, economic and structural contexts shape citizen behavior and condition democratic choice; the nature of political and social divisions; and how citizens in different political systems evaluate democratic institutions and processes. Participating countries include a common module of survey questions in their post-election studies. The resulting data are deposited along with voting, demographic, district and macro variables. The studies are then merged into a single, free, public dataset for use in comparative study and cross-level analysis. The research agenda, questionnaires, and study design are developed by an international committee of leading scholars of electoral politics and political science. The design is implemented in each country by their foremost social scientists.