did2s: Two-Stage Difference-in-Differences

Abstract

Recent work has highlighted the difficulties of estimating difference-in-differences models when the treatment is adopted at different times for different units. This article introduces the R package did2s which implements the estimator introduced in Gardner (2022). The article provides an approachable review of the underlying econometric theory and introduces the syntax for the function did2s. Further, the package introduces functions, event_study and plot_event_study, which uses a common syntax to implement all of the modern event-study estimators