A powerful new research design in the field of voter mobilization has created a more comprehensive picture of the effectiveness of various get-out-the-vote campaign methods. With an increase in field experiments in the past few years, researchers, campaigns, and policymakers have gleaned important insights into voter participation.

Until recently, voting behavior was mainly studied through survey research. And while large national surveys have had a tremendous impact on scientific and policy debates, concerns about the accuracy of survey research remain. Surveys suffer from two...