“…Other studies use variation in indexes summarizing the strictness of diverse policies for teens in the United States. Findings are mixed, with studies reporting positive, negative, or statistically imprecisely estimated correlations between such indexes and smoking prevalence among teens (see, e.g., Gruber and Zinman, 2000;Cawley, Markowitz and Tauras, 2006;Nesson, 2017). 5 As these indexes are a summary measure for diverse policy tools for preventing teen smoking (including packaging restrictions, regulations on possession, minimum smoking age, restrictions on free distribution of samples, advertising, licensing, and regulation of use) it is 4 We are only aware of one case study by Macinko and Silver (2018) which uses both, several yearly waves of cross-sectional data prior to the adoption of a higher minimum legal purchase age and a comparison group.…”