SUMMARY/ABSTRACT The current P01 grant supported the creation of the International Tobacco Control Policy Evaluation (ITC) Project Four Country Smoking and Vaping Survey, the first international cohort study of smoking and nicotine vaping product (NVP) use, which was conducted in three countries supported by the P01 grant (United States [US], Canada, England, plus Australia, which was supported by other funding). Three waves were conducted, an average of 19 months apart, in 2016, 2018, and 2020. In this renewal application, we build on that work by matching the extraordinary international expansion of the nicotine marketplace by adding a focus on heated tobacco products (HTPs) in addition to cigarettes and NVPs. We propose to continue the adult cohort survey in US (n=2,150), Canada (n=2,150), and England (n=2,300) for 3 additional waves, 19 months apart, over the next 5 years, with a substantial expansion by adding adult cohort surveys from 4 other ITC countries, which are being supported by funding sources outside this proposed grant: Japan (n=4,500) and the Republic of Korea (n=4,700), countries that are the epicenter of the tobacco industry's introduction of HTPs; New Zealand (n=1,600), which has incorporated NVPs into their “endgame” strategy; and Australia, which continues its more restrictive approach to these Alternative Nicotine Delivery Systems (ANDS) (n=1,500; grant application pending). The resulting 7-country ITC Nicotine Product Adult (NPA) Survey (total n=18,900) will represent an innovative international evaluation system that will allow the research team to conduct a comprehensive research program on the use of nicotine products, and transitions between cigarettes and nicotine products, building on the ITC Project's 18-year global experience in conducting rigorous evaluation of tobacco control policies, employing quasi-experimental analytic methods. The NPA Survey will provide important evidence to advance the science and understanding of nicotine products and policies during the next five years, which is certain to be a period of dynamic change in the nicotine product marketplace. Similar studies in the US such as the Population Assessment Tobacco and Health (PATH) are limited since they do not readily permit cross- country comparisons using harmonized measures as the NPA survey does. This innovative Project has three Specific Aims: 1) to describe patterns use of and transitions of use across different tobacco products among smokers and recent ex-smokers both over time and by key user characteristics within and between countries; 2) to examine how differences in current and future policies (e.g., taxes, flavor bans, product standards, health warnings) for cigarettes, NVPs, and HTPs are related to differences in patterns of use of these products over time; and 3) to examine the relative impact of policies on adults and youth (a Specific Aim shared with Project 2). Two exploratory aims will also be addressed given their likely impa...