Before revision:  We focus on parameters aggregating instantaneous and dynamic treatment effects, as a way to evaluate the welfare effects of the policies that occurred over the duration of the  panel.
After revision:  We consider two sets of parameters of interest. The first are the average effects of having changed treatment for the first time \ell periods ago. Those parameters generalize the average effect of having started receiving the treatment \ell periods ago that has often been estimated in applications with a binary treatment and staggered adoption. We also consider cost-benefit ratios a planner may use to compare the treatments actually assigned to a counterfactual panel.