A person’s health status is largely determined by factors outside the control of the healthcare sector. While some of these are fixed, such as inheritance, many are environmental in the broadest sense of the term. These operate through such socioeconomic sectors as employment, education, housing and transport, which structure the health risks and opportunities of individuals. Typically the structuring is unequal—sometimes referred to as clustering of disadvantage—so that those who are less well placed socioeconomically also have worse health outcomes, contributing to socioeconomic inequalities in health.

The health impacts of these sectors can be influenced by interventions, whether or not these are primarily motivated by health considerations. For example, a policy or other intervention to improve educational status can raise the socioeconomic standard, thereby improving health. Such interventions have the potential to increase or decrease inequalities.

AIMS AND BASIC CONCEPTS OF HEALTH IMPACT ASSESSMENT

Health impact assessment (HIA) is concerned with the health of populations.¹ It generally attempts to predict the future health consequences—both positive and negative impacts—of an intervention such as a policy,² programme, or project³ (hereafter collectively referred to as a “proposal”).^1,4,5 There are several definitions of HIA in the literature; for example, “a combination of procedures, methods and tools by which a policy, program or project may be judged as to its potential effects on the health of a population and the distribution of effects within the population”.⁶ The overall aim when conducting an HIA is to influence decision making to minimise the harm and maximise the health benefit of proposals.⁷ This might happen in three ways: (1) by raising the general awareness among decision makers that their actions affect health; (2) by informing decision makers of the likely specific impacts of particular decisions; and (3) by helping those potentially affected by decisions to participate in proposal …