24/7 Tempo created an index modeled after an analysis conducted by County Health Rankings & Roadmaps, a Robert Wood Johnson Foundation and University of Wisconsin Population Health Institute joint program. To identify the 25 healthiest cities, 24/7 Tempo reviewed all U.S. metropolitan statistical areas. The index rankings are based on overall health outcomes, a weighted composite of length of life, quality of life, and overall health factors. The health factors component is itself a weighted composite of healthy behaviors, clinical care, social and economic factors, and physical environment measures. Median household income figures came from the Census Bureau’s 2017 American Community Survey.