Policy research examines the impact of policy and environmental interventions on the prevention or cessation of tobacco use. INTRODUCTION Public and private policy changes are critical to the success of tobacco control because of their potential to create a social, policy, media, and economic environment conducive to reducing tobacco use and exposure among children, youths, and adults. Such an environment can reduce tobacco use among large populations. Policy research should focus on understanding the complex relationships that link the social context, the public health agenda, tobacco use, and individual behavior change. Determining these relationships will inform policymakers and tobacco-control program planners about those policies and programs that are most likely to be effective. As described in the Community and State Research section of this report, decreases in tobacco use have resulted from policies that increase the price of tobacco, restrict its marketing, and restrict where it can be used. It is clear, for example, that tobacco price and tax increases affect youth and adult smoking patterns. It is less clear what effect price increases have on intentions to start or quit smoking, or how gradual, small price increases compare to lump-sum, large increases in terms of their impact on tobacco consumption or choice of brands. We also need to clarify the extent to which counter-advertising campaigns, retailer compliance checks, or school-based prevention programs heighten the public health impact of tobacco price increases. Taken together, such research will help determine the relative impact on the use of tobacco among youths of policies that increase prices and those that reduce tobacco advertising and promotion. We also need policy research to provide science-based answers to a number of other questions. How, for example, does tobacco marketing interact with biobehavioral factors (e.g., culture, social influences, and personality) to influence youth susceptibility to tobacco use? Research should also focus upon how price increases and youth access laws affect different segments of the population. The effect of product design, including amount of nicotine and mode of delivery, upon nicotine use and dependence among users may also be evaluated. Finally, the relative costs and benefits of mandating Medicaid coverage for nicotine addiction treatment is worthy of inquiry. Policymakers and tobacco control program planners need answers to these questions. Furthermore, the potential to link policy research to research on the state and community interventions as described below provides a unique opportunity to maximize the impact on tobacco use from both lines of research. RECOMMENDATIONS Research should be conducted to understand the impact of tobacco policies, including taxation and pricing, clean indoor air policies, marketing restrictions, youth access restrictions, and tobacco product and nicotine replacement regulation. Research to evaluate the impact of individual and combined policy and environmental interventions is needed. Much can be learned about controlling tobacco use through studies that evaluate the multitude of "natural experiments" occurring as a result of existing and expanding state and local tobacco control programs described in the previous section. For instance, policy research could evaluate the impact of naturally occurring differences in the price of cigarettes and other tobacco products in different communities, the success of efforts to curb youth tobacco advertising/promotion, and the effects of variations in school-based tobacco control policies and sanctions. Such research also should examine the extent of enforcement of youth access laws and whether such policies should penalize youth or retailers or both. We need research on policies to improve Americans' access to effective nicotine addiction treatment aids and tobacco cessation interventions. This research should examine and assess the impact of treatment reimbursement policies on tobacco use, disincentives for tobacco use, system changes to promote routine tobacco cessation intervention in primary health care settings, and managed care tobacco performance accountability measures. Policy research also is needed to determine the optimal allocation of treatment resources for the greatest population impact. The NCI's new research network of managed care organizations provides an important opportunity to examine alternative access-enhancing strategies. Most past policy research relied upon cross-sectional analyses, which are limited in their usefulness. High priority should be placed on conducting prospective, long-term policy research that can demonstrate cause-effect relationships and indicate the impact of various policies on transitions in tobacco-use patterns over time. Mechanisms for "quick strike" or "rapid response" studies should be included to allow investigators to seize opportunities to evaluate natural policy experiments. Furthermore, methodologies for assessing the implementation and impact of these interventions should be expanded and refined. Research to inform policymakers about the design and marketing of tobacco and nicotine-replacement products represents another important avenue for research. To improve future regulation of such products, the NCI should consider funding research on harm-reduction strategies aimed at both youth and adult smokers. For youth, research could examine the impact of product design, including level of nicotine and mode of delivery on nicotine use and dependence. Research could examine the effects of long-term nicotine maintenance, alternative nicotine delivery devices, and reduction in tobacco toxins for highly addicted adult smokers. These studies could evaluate the biological, behavioral, social, and economic consequences, both intended and unintended, of modifying and substituting different tobacco products. It should be made clear that studying these strategies does not represent an endorsement of them. Research on harm-reduction approaches should also include investigations of the behavioral and health impacts of policies and interventions designed to reduce environmental and occupational exposures to environmental tobacco smoke (ETS). This also is referred to as second-hand smoke or passive smoking. Basic biological research on the extent of the role ETS plays in tobacco-related lung cancer can play an important role in forming such policies. The rapid global increase in the consumption of tobacco products has accelerated the need for coordinated international research efforts to reduce the morbidity and mortality associated with this global pandemic. The NCI can take the lead in research to examine cross-national differences in tobacco-control policies as well as learn from effective foreign tobacco-control policies. International research can help clarify the impact of advertising restrictions and excise taxes on tobacco use. Tobacco products, as well as social, cultural, and environmental factors, vary from country to country. Consequently, international research can look at important questions concerning tobacco control in the design, packaging, and marketing of tobacco products that cannot be studied in the United States alone. A vital investment in international tobacco control research would be to increase the surveillance capacity of countries to monitor tobacco use, tobacco-control policy development, and tobacco-control efforts. The NCI could also make a significant contribution by providing training opportunities to international physicians and policy researchers to promote tobacco control in their countries. THE IMPACT OF POLICY RESEARCH Policy research, especially in combination with the state and community research discussed in the previous section, has the potential to affect the most wide-reaching interventions currently used in tobacco control. Effective public and private policies can reduce tobacco use among populations of entire states and nations. The research proposed in this section can make tobacco control policies more effective and point the way to the next generation of more powerful programs and policies for preventing tobacco use and nicotine addiction.