PROJECT 3 Abstract In the US, at least six states and hundreds of localities have restricted or banned sales of flavored electronic nicotine delivery systems (ENDS) in order to reduce youth vaping. Yet the evidence on these policies’ effects on individual behavior is mixed, and some studies link them to increases in combustible cigarette use (“smoking”). Nationally generalizable estimates for such regulations’ effects on contemporaneous cigarette, cigar, and ENDS use—the three most popular tobacco/nicotine products in the US—are needed to clarify the policies’ immediate impacts and model longer run effects on these behaviors as well as related health outcomes and disparities. Thus, focusing on the Behavior and Impact Analysis scientific domains described in RFA-OD-22-004, we will apply quasi-experimental research designs—methods designed to produce causal estimates in the absence of randomized assignment—to nationally representative, restricted-use survey data on adults and adolescents as well as retail sales data, in order to clarify such flavor restrictions’ effects. Matching these datasets to data on state and local ENDS flavor restrictions, Aim 1 will estimate ENDS flavor restrictions’ effects on youth and adult smoking and vaping, with sensitivity checks testing whether effect estimates vary with policy attributes (e.g., retailer exemptions). To consider differential effects by urbanicity and socioeconomic status (SES), Aim 2 will then test whether responses to flavor restrictions vary across urban vs. rural jurisdictions; assess the extent to which this might be explained by geographic factors (e.g., proximity to jurisdictions that allow flavored ENDS sales) vs. differences in resident characteristics (e.g., SES); and, estimate implications for both urban-rural and SES disparities in smoking and vaping. As a federal flavor restriction’s impacts may differ across areas with distinct state and local tobacco control policies, Aim 3 will assess how flavor restrictions’ effects differ between localities with more vs. less restrictive tobacco control policy environments. Those results will be used to estimate implications for the effectiveness of a federal flavor ban, given observed variation in local policies. Finally, to further aid the Food and Drug Administration in evaluating new policies’ effects, Aim 4 will use retail sales data to provide rapid analyses of new federal flavor regulations’ relationships to tobacco/nicotine product sales (e.g., banning sales of menthol cigarettes or non- tobacco flavored cigars) and consider associations with sales of newer non-nicotine flavoring products, intended for use with cigarette, cigar, and/or ENDS, in order to understand if/how their availability modifies flavor laws’ effects. Thus, this research will clarify flavor restrictions’ effects on youth and adult rates of cigarette, cigar, and ENDS use, providing key parameters to inform our Center’s modeling of flavor restrictions’ long-term public health impacts, in order to aid CTP in assessing the impact of FDA flavor policies.