“…3 Large regional disparities prevail not just for healthcare costs (OECD, 2014;Skinner, 2011), but also for health and mortality (Banks et al, 2021;Chetty et al, 2016;Currie & Schwandt, 2016). A growing literature documents the role of place effects in explaining such disparities (Atella et al, 2019;Deryugina & Molitor, 2020Finkelstein et al, 2021;Johnson & Taylor, 2019). In these studies, population sorting and selective migration is not an object of interest, but a potential source of bias that needs to be controlled for by careful research designs.…”