Health Impact Assessment: Necessary but Not Sufficient for Healthy Public Policy

mated that health-care access and quality are responsible for only 10%-50% of avoidable morbidity and premature mortality.59 Although much is still unknown about the mechanisms explaining the associations between societal (including social, physical, and economic) determinants and health, factors such as lower levels of education and income have, with few exceptions, been linked repeatedly and strongly to poorer health, with dose-response relationships that support causal links.10,11 While an appreciation for the social, physical, and economic determinants of health, disease, and injury is not new,12 momentum for addressing these determinants has been increasing. One contributing factor has been a rising awareness of the economic consequences of avoidable illness and premature death in the form of both increased health-care costs and decreased productivity11,13 and the cost-effectiveness of many prevention-oriented population-level interventions.14 A second critical factor has been a push by the World Health Organization (WHO) for more attention to a range of underlying health determinants beyond health care. This increased emphasis began visibly in the late 1970s with WHO's Primary Health Care initiative calling for joint action across multiple sectors (e.g., education, agriculture, housing, labor, urban planning, transportation, and health care) to improve health, both directly and indirectly.15,16 WHO has subsequently developed and promoted more detailed, concrete recommendations for how governments and nongovernmental organizations can help create healthy communities by addressing societal factors.3,1720 One aspect of the WHO recommendations has generated substantial interest in the United States. Health Impact Assessment (HIA) is a systematic process