The Cooperative Election Study (CES) is the largest academic survey focused on American elections. Since 2006, the study has interviewed more than a half-million Americans to capture their views on contemporary policy debates, their engagement in political and social life, and their vote choices in federal and state elections. The study is a collaborative enterprise partially funded by the National Science Foundation and involving the participation of hundreds of scholars and students across dozens of academic institutions across the country. 

During election years, the survey consists of interviews with more than 50,000 American adults before and after the election. During the pre-election wave, respondents answer questions about their general political attitudes, various demographic factors, assessments of policies being debated in Congress, political information, and vote intentions. In the post-election wave, respondents answer questions about how they voted in the election and other ways in which they have recently engaged in political and social life. In non-election years, the survey consists of a single wave conducted in the fall.

The data from the CES are used widely by researchers, journalists, and members of the public to understand American elections and public opinion. Few, if any, data infrastructure ventures in the discipline have participation from as many institutions and scholars as CES has facilitated.