“…Timmer and Williamson (, ), for instance, focus on broad measures of stringency in legislation in the late nineteenth and early twentieth centuries; the Migration Integration Policy Index focuses on policies regulating integration (Niessen et al. ); Kogan () examines “relative selectivity” surmised from immigration flows and their native counterparts;Ortega and Peri (), Mayda (), and de Haas, Natter, and Vezzoli () gauge broad legislative reforms over time within countries; Bélot and Ederveen () track cultural barriers to immigration; and (Ruhs ) measures policies regulating the social rights of migrant workers. Other efforts have examined particular features of policy, including asylum and refugee policies, particularly in Europe (Thielemann , , ; Hatton , ; Neumayer ; Lowell ; Cerna ; Czaika ), and citizenship policies (Waldrauch and Hofinger ; Howard , , ; Koopmans et al.…”