Differing forms, differing purposes: A typology of health impact assessment

There is currently considerable diversity in health impact assessment (HIA) practice internationally. Historically this diversity has been described as simple dichotomies, for example the differences between HIAs of projects and policies. However these distinctions have failed to adequately describe the differences that can be observed between different forms of HIAs. This paper describes the three historical and disciplinary fields from which HIA has emerged — environmental health, a social view of health, and health equity. It also puts forward a typology of four different forms of HIA that can be observed in current HIA practice: mandated, decision-support, advocacy, and community-led HIAs. This paper argues that these different forms of HIA serve different purposes and are not necessarily in competition; rather they allow HIA to be responsive to a range of population health concerns and purposes.