We study a novel dataset compiled from archival records, which includes information on men's wages, union status, educational attainment, work history, and other background variables for several cities circa 1950. Such data are extremely rare for the early post-war period when U.S. unions were...

This paper analyzes difference-in-differences designs with a continuous treatment. We show that treatment effect on the treated-type parameters can be identified under a generalized parallel trends assumption that is similar to the binary treatment setup. However, interpreting differences in...

This paper considers methods for defining aggregate parameters of interest in a difference-in-differences design with a continuous and staggered treatment. It also discusses how aggregation choices often simplify estimation