Recent work has highlighted the difficulties of estimating difference-in-differences models when treatment is adopted at different times for units. This article introduces R package did2s which implements estimator introduced in @Gardner_2021. The provides an approachable review underlying econometric theory and syntax function `did2s`. Further, functions, event_study plot_event_study, uses a c...

• First treatment of standard quadratic optimization problems under uncertainty with two-stage stochastic approach. Efficient and tractable upper lower bounds for this NP-hard problem. Modern first-order method (pairwise Frank-Wolfe) enhanced copositive techniques aim at scalability bounds. Two-stage decision are characterized by the property that in stage one part has to be made before relevan...