The Comparative Study of Electoral Systems (CSES) is a collaborative program of cross-national research among election studies conducted in over fifty states. The CSES is composed of three tightly linked parts: First, a common module of public opinion survey questions is included in each participant country's post-election study. These "micro" level data include vote choice, candidate and party evaluations, current and retrospective economic evaluations, evaluation of the electoral system itself, in addition to standardized sociodemographic measures. Second, district level data are reported for each respondent, including electoral returns, turnout, and the number of candidates. Finally, system or "macro" level data report aggregate electoral returns, electoral rules and formulas, and regime characteristics. This design allows researchers to conduct cross-level, as well as cross-national analyses, addressing the effects of electoral institutions on citizens' attitudes and behavior, the presence and nature of social and political cleavages, and the evaluation of democratic institutions across different political regimes. 

ASEP/JDS has contributed to the CSES, via ICPSR, in producing the official CD-Rom for CSES-Module 1, which includes data on 39 elections carried out in 33 countries during the period 1996-2001 and depositing Module 1 in the databank for online analysis