Overview & History
Health Impact Assessment (HIA) is defined as "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 those effects within the population." (Gothenburg Consensus Paper Page 4)
HIA is intended to produce a set of evidence-based recommendations to inform decision-making. HIA seeks to maximise the positive health impacts and minimise the negative health impacts of proposed policies, programs or projects.
The procedures of HIA are similar to those used in other forms of impact assessment, such as environmental impact assessment or social impact assessment. HIA is usually described as following the steps listed, though many practitioners break these into sub-steps or label them differently:
- Screening - determining if an HIA is warranted/required
- Scoping - determining which impacts will be considered and the plan for the HIA
- Identification and assessment of impacts - determining the magnitude, nature, extent and likelihood of potential health impacts, using a variety of different methods and types of information
- Decision-making and recommendations - making explicit the trade-offs to be made in decision-making and formulating evidence-informed recommendations
- Evaluation, monitoring and follow-up - process and impact evaluation of the HIA and the monitoring and management of health impacts (refer to page on impact assessment follow-up)
The main objective of HIA is to apply existing knowledge and evidence about health impacts, to specific social and community contexts in order to develop evidence-based recommendations that inform decision-making. This is done in order to protect and improve community health and wellbeing. Financial and time constraints mean that HIAs do not always involve new research or the generation of original scientific knowledge. However, the findings of HIAs, especially where these have been monitored and evaluated over time, can be used to inform other HIAs in contexts that are similar. An HIA's recommendations may focus on both design and operational aspects of a proposal.
HIA has also been identified as a mechanism by which potential health inequalities can be identified and redressed prior to the implementation of proposed policy, program or project - see for example the UK Acheson Report (1998) or the WHO Closing the Gap in A Generation (2008) reports).
The use of HIA can be seen as evolving from three origins:
- HIA as a part of environmental impact assessment
- HIA as an approach for intersectoral action on the broader determinants of health
- HIA as a mechanism to reduce and redress health inequities
Figure 1: Selective timeline of the development of Health Impact Assessment (Source: Harris-Roxas & Harris (2010))