This article discusses the lessons learned from the experience of designing and using a population health information system and the policy implications of information generated. A useful system must include measures of the population's health status and socioeconomic risk when analyzing health care use. The strong gradient that can be demonstrated in service use across income groups where these indicators are included challenges policymakers and health care managers to rethink fundamental beliefs about the role of medical care. Given the size of health care expenditures in western economies, the author argues for redirecting some of these resources toward other means of improving the health of populations. Outcomes research should be expanded to assess the efficacy of non-medical and medical interventions. A population-based health information system can help identify opportunities for shifting expenditures toward meliorating the determinants of health, while monitoring the health care system to ensure that adverse effects do not occur.