Public health research encompasses biostatistics, epidemiology, surveillance, and health policy as well as specific programs to prevent disease and promote health. HZA’s work includes creating and maintaining the statewide epidemiological profile for substance abuse and mental health in Maine, evaluating targeted programs such as medication assisted treatment for drug addiction, and evaluating public health interventions designed to increase access to primary care, promote physical activity and healthy eating and prevent diabetes. Prevention programs are notoriously difficult, because they almost necessarily involve predicting what would have happened if the program had not been in place. HZA has pursued both of the widely accepted solutions to that problem. The first is to measure changes in factors which have been shown to be associated with the occurrence or non-occurrence of a negative event, while the second is to measure broad population changes. Both strategies are reflected among the projects below. In addition to state agencies, HZA has worked with community based non-profit organizations and health systems to develop and evaluate these public health interventions.