Abstract This is an application for the Pathway to Independence Award (K99/R00) for Dr. Daniel Taber, a postdoctoral research associate at the Institute for Health Research and Policy (IHRP) at the University of Illinois at Chicago (UIC). Dr. Taber is a young investigator who specializes in studying the effects of school- based policies that are designed to improve diet and reduce obesity among children. He also specializes in studying racial/ethnic disparities in school policy effectiveness. The K99/R00 award will enable him to expand his policy research to sectors outside of school, as he examines how economic, environmental, and policy measures in the community (e.g., taxes, zoning laws) modify the effects of school-based legislation. His proposed research includes system dynamics modeling designed to simulate the comprehensive effect of policies in different sectors. Many experts have recommended applying systems science to obesity policy research, but the application of systems science has been largely theoretical. Dr. Taber received introductory training in system dynamics at the 2011 Institute on Systems Science and Health (ISSH) and is now proposing to pursue in-depth training in this field. His proposed training will include: 1) formal coursework in system dynamics, 2) one-on-one training in economic and environment policy initiatives, and 3) one-on-one training in economic methods of studying disparities and policy initiatives. To achieve these goals, he has assembled a mentoring team with expertise in public policy (Dr. Jamie Chriqui, UIC), economics (Dr. Frank Chaloupka, UIC), and system dynamics (Dr. Hazhir Rahmandad, Virginia Tech). Dr. Chriqui and Dr. Chaloupka have decades of experience studying economic and environmental policies related to substance abuse, and are currently conducting ground-breaking research to study whether such policies can prevent obesity. Dr. Rahmandad was Dr. Taber's instructor at ISSH, earned his PhD in system dynamics at the Massachusetts Institute of Technology, and is currently conducting obesity research to study the dynamics of energy balance. Dr. Taber's mentors will guide him through his proposed research, in which he will study whether economic and environmental characteristics in the community modify the effects of school-based policies (Aims 1 and 2), analyze whether such characteristics contribute to racial/ethnic disparities in weight status and policy effectiveness (Aim 3), and apply system dynamics to analyze the impact that policy initiatives in different sectors have on diet, weight status, and racial/ethnic disparities in weight status among adolescents (Aim 4). This research will form the basis of an R01 application in which he will design more intensive system dynamics research to study the effects of obesity policies, and he will complete this application by the end of the R00 phase of this award.