“…Given the selection issues inherent to most observational designs studying contact, much work in this literature takes the form of randomized experiments. 6 Other papers exploit natural experiments, such as the random assignment of roommates or classmates (Boisjoly et al, 2006;Rao, 2019;Carrell et al, 2019;Corno et al, 2019;Scacco and Warren, 2018), the random composition of military bootcamp cohorts (Dahl et al, 2020;Finseraas and Kotsadam, 2017) or the random assignment of province or country for military or missionary deployment (Bagues and Roth, 2020;Crawfurd, 2020). An important theme is this literature persistence: some studies (Bazzi et al, 2019;Bagues and Roth, 2020) find that effects persist over years or decades, while others (e.g.…”