This seminar is an introduction to designing field experiments in the social sciences. Field experiments involve: (1) random assignment of an intervention; and (2) measurement of behavioral responses to the intervention in a field setting. In this seminar, we will explore design principles for field experiments and common challenges encountered when implementing and analyzing data from field experiments. We will also consider the ethics of field experimental research. Each participant will be asked to design a field experiment that serves their research goals, participate actively in discussions, and complete short, weekly problem sets.