Campbell Workshop: A Guide to the DiD Revolution

Amanda Weiss, assistant professor of political methodology in the Department of Government at Cornell University.

What do we do when we can't experiment? A revolution in difference-in-differences (DiD) research has yielded a flood of new methods for studying the effects of policy and natural shocks under relatively weak assumptions. This workshop offers applied researchers an intensive treatment of modern DiD: why the once-ubiquitous two-way fixed effects estimator fails, the major classes of new estimators that replace it, tools for testing identifying assumptions, and persistent challenges for inference—all grounded in the real-world data problems that made this revolution necessary.