AcademyHealth's Public Health Systems Research (PHSR) Interest Group recognized "Why Behavioral and Environmental Interventions Are Needed to Improve Health at Lower Cost" as the PHSR Article of the Year. The article was selected for its relevance to current health policy, unique and innovative methods, and strong potential to challenge current thinking. AcademyHealth invited lead author Bobby Milstein, Ph.D., M.P.H., to share his thoughts below on how his award-winning work demonstrates innovation within the field of PHSR.  Though a majority of Americans firmly endorses the need for fundamental health system change and there is widespread agreement that the United States spends too little to protect and improve the nation’s health, there is virtually no consensus among Americans about how to achieve the main objectives of better health, better care, lower cost, and greater equity. Indeed, the ongoing debate about the Affordable Care Act and the Supreme Court’s narrow decision to uphold most elements of the law show just how deeply our controversy over national health reform strategy runs. Fortunately, the growing field of public health systems research (PHSR) is beginning to point the way toward viable solutions. Last month, AcademyHealth’s PHSR Interest Group identified five noteworthy articles published in 2011 that together demonstrate the power and poignancy of PHSR. Each of these papers offers compelling evidence about practical opportunities to enhance health through cost-effective investments. My colleagues Jack Homer, Peter Briss, Terry Pechacek, Deron Burton, and I are honored to have been recognized among this group and we were delighted to learn that our research on the importance of behavioral and environmental interventions to improve health at lower cost was selected by the PHSR Interest Group as PHSR Article of the Year. Using the HealthBound policy simulation model, we explored the likely health and economic impacts from three of the most common national reform strategies: (1) expanding health insurance coverage; (2) delivering better preventive and chronic care; and (3) protecting health by enabling healthier behaviors and improving environmental conditions. The results demonstrated that each strategy alone could save millions of lives and provide solid economic value, but are likely to be much more effective when enacted together and viewed over the long-term. Several commentators, including David Kindig and the Robert Wood Johnson Foundation, have observed that this sort of simulation science is a particularly compelling way to explore “What If…” scenarios and to compare the likely return-on-investments from diverse interventions, including those that span the conventional divide between population health and individual health care. Over the past few years, with support from the Fannie E. Rippel Foundation, the California HealthCare Foundation, and scores of organizational allies, members of ReThink Health have also embraced the power of simulation modeling. Through the ReThink Health Dynamics program, we have picked up where the national HealthBound modeling project left off by creating a suite of new models to represent key features of local health systems. We are also embedding those models with complementary tools to engage and support local leaders who are committed to transformation. A brief demonstration of the ReThink Health Dynamics model was featured during a methods session at the Annual Research Meeting in Orlando. Across the country, innovators working with ReThink Health are beginning to learn new ways of organizing diverse teams for collective action, establishing the conditions for long-term stewardship of local health resources, and simulating the dynamics in different regions that may spark and sustain significant system-wide improvements. Together, these tools bring greater structure, evidence, and creativity to the challenge of local health system change. They help leaders anticipate the consequences of new actions—and confront the stakes of continued inaction. This approach combines evidence with relationship-based experiences to move leaders outside their comfort zones, while at the same time supporting them as they work together to seed innovations and drive measurable improvements over time. Moreover, as an action-research project, the ReThink Health endeavor is pushing the boundaries of what future public health systems research might accomplish. We welcome comments and inquiries on how these tools might advance your own efforts to catalyze local health system change. Bobby Milstein, Ph.D., M.P.H., is director of ReThink Health Dynamics, a project of ReThink Health, and director of Systems Strategy and Programs for the Fannie E. Rippel Foundation. He also has academic appointments at the MIT Sloan School of Management and the Boston University School of Public Health. From 1991 to 2011, he worked at the Centers for Disease Control and Prevention, where he founded the Syndemics Prevention Network, chaired the agency’s Behavioral and Social Science Working Group, and coordinated planning/evaluation activities for new initiatives on a variety of topics.