The evolving nature of Health Impact Assessment has lead to many formal and widely accepted definitions.
In Australia the most common definition for HIA was developed by the European Centre for Health Policy (ECHP), World Health Organisation (WHO) in the 1999 Gothenburg consensus paper on HIA.
"Health Impact Assessment is 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."
Thus in its broadest sense, HIA aims to predict or assess both the positive and negative direct and indirect impacts of a policy, program or project on human health. Human health being defined as
"...a state of complete physical, mental and social wellbeing and not merely the absence of disease or infirmity"
The methodology of HIA within Australia and New South Wales at the project level is similar to EIA. It is the emphasis that is different. EIA seeks to examine the environmental consequences of development actions. HIA attempts to assess the impacts of a development, program or policy on the health of the population. As humans are part of the environment, overlap between the two is common. However traditionally EIA has restricted itself to only examining the potential harmful effects a development may have on the immediate community. This assessment is generally confined to environmental hazards such as chemical contamination.
HIA attempts to expand this knowledge to look at the social, economic, lifestyle and behavioural costs and benefits to the immediate community as well as the 'downstream' direct and indirect impacts that will occur in other communities.
At a policy or program level, HIA is more akin to Strategic Environmental Assessment (SEA), although the focus is human health impacts rather than environmental impacts.
The EnHealth Council has released guidelines for Health Impact Assessment. Please contact the enHealth Secretariat (enHealth.Secretariat@health.gov.au) if you would like to receive an electronic copy of the publication.
In NSW, the Centre for Health Equity Training Research and Evaluation (CHETRE) is currently working to integrate HIA into the NSW Health System. Their newsletters and other information about HIA may be accessed via http://www.hiaconnect.edu.au/