Health Impact Assessment (HIA) is ‘a combination of procedures, methods and tools by which a policy, programme 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’[World Health Organisation Regional Office for Europe 1999 4]. Its purposes are minimising health loss and maximising health gain [Winters 1997]. 

In Ireland, the term ‘health proofing’ is sometimes used interchangeably with HIA. HIA generally assesses the health effects of interventions that are not primarily aimed at effecting health [Boothroyd 1995 in Burney 1999]. A formal HIA should be considered when there is uncertainty or concern about possible health risks of a proposal, or possible opportunities to increase health gain [Scottish Needs Assessment Programme 2000]. 

HIA is developing globally as a significant opportunity to make policies, programmes and projects ‘health conscious’ [Milner 1999 54].