In the social sciences, randomized experimentation is the optimal research design for establishing causation. However, for a number of practical reasons, researchers are sometimes unable to conduct experiments and must rely on observational data. In an effort to develop estimators that can...

Voter mobilization experiments are often conducted using individual-level randomization, which can be difficult to implement. A simpler approach is to randomly assign voting precincts, rather than individuals nested within them, to treatment and control groups. Not only is it easier and...