Causal Models for Longitudinal and Panel Data: A Survey

This survey discusses the recent causal panel data literature. This recent literature has focused on credibly estimating causal effects of binary interventions in settings with longitudinal data, with an emphasis on practical advice for empirical researchers. It pays particular attention to heterogeneity in the causal effects, often in situations where few units are treated. The literature has extended earlier work on difference-in-differences or two-way-fixed-effect estimators and more generally incorporated factor models or interactive fixed effects. It has also developed novel methods using synthetic control approaches.