Epidemiologic approaches to policy research - examinations of single policies, policy clusters, and policy climates: Conceptualization, measurement, and analysis.

Given intensifying political polarization and sweeping legal actions targeting marginalized populations across the U.S., there are increasing calls to examine how these policy changes are shaping population health and health inequities. To meet these calls, researchers have developed and applied various approaches to support rigorous, theoretically-informed quantitative research on policies and health. To date, much of the literature has examined single policies; however, there is growing interest in examining alternative ways of conceptualizing policy exposures, namely as policy clusters or policy climates, to better capture how policies are enacted (and experienced) in "real-world" contexts. To advance this work, greater clarity is needed regarding how different approaches to policy conceptualization, measurement, and analysis align with distinct research questions and goals, ranging from identifying specific, manipulable policy levers to informing ways of extending the "policy space" beyond already existing laws to support broader social change. In this essay, we help fill this gap by outlining key issues related to policy exposures, including conceptualization, methods for measure development, and analytic approaches for understanding the relationship between policies and health. We end by discussing future directions for population health research on single policies, policy clusters, and policy climates, with an eye towards advancing health equity.