Health Impact Assessment

Health Impact Assessment

Health Impact Assessment is the technical name for a common sense idea. It is a process that considers the wider effects of local and national policies and initiatives and how they, in turn, may affect people’s health and wellbeing. Some of these may be positive, and others could be detrimental and require mitigation.

The idea is to ensure that any proposed initiative can be adjusted to maximise benefits in terms of its effects on local health and minimise any harm. HIA seeks to address existing health inequalities and inequities as well as avoid the creation of new ones. As we move towards the integration of policy and services, HIA is an ideal tool for integrating the promotion of health and wellbeing into a wide range of policies, programmes and services.

The European Centre for Health Policy (1999) Gothenburg Consensus is widely accepted as the seminal definition of Health Impact Assessment and defines it as:

‘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’

However, alternative definitions have recently been proposed (Elliott et al. 2010) as the practice of HIA has evolved:

‘...a process through which evidence (of different kinds), interests, values and meanings are brought into dialogue between relevant stakeholders (politicians, professionals and citizens) in order imaginatively to understand and anticipate the effects of change on health and health inequalities in a given population’.

The second definition recognises that the direction and nature of health impacts are not obvious
or universally accepted, are subject to debate and involve different ideas about what health is and
what the conditions for health should be. HIA nonetheless provides a framework through which
different views of evidence and health can both be made explicit and scrutinized.

HIA is a systematic, objective and yet flexible and practical way of assessing both the potential
positive and negative impacts of a proposal on health and well-being and suggests ways in which
opportunities for health gain can be maximized and risks to health minimised. HIA looks at health in
its broadest sense, using the wider determinants of health as a framework.

Importantly, HIA highlights the uneven way in which health impacts may be distributed across a population and seeks to address existing health inequalities and inequities as well as avoid the creation of new ones. HIA is a tool to support decision making and, as such, it can inform decision makers and communities of the potential health and well-being impacts and consequences of a proposal or policy.

HIA is not in itself the means of making a decision on whether a policy, proposal or programme should proceed. It is a way of harnessing a wide range of evidence and assessing its relevance and application to a particular local, regional or national context.

However, there are different kinds of knowledge, some of which is the contextual knowledge that
communities have of the places in which they live. Furthermore, the decisions that are made may
have a profound effect on people’s quality of life. Questions of knowledge and values are therefore
closely connected and there is a need to ensure that the processes for assessing evidence of all kinds
are robust, inclusive and transparent.

Wherever possible assessments should be conducted in partnership with representatives of stakeholder groups (those affected by, and/or have an interest in, the proposal in question). HIAs make use of any relevant evidence and expertise that would help them to make judgements about the potential impacts and is therefore a mechanism to support evidence and knowledge based decision making.

Integrated decision making and the determinants of health

The environment, income, employment, the organisation of transport, the design and condition of houses, crime and the social and physical condition of local neighbourhoods all contribute to the health and wellbeing of individuals and communities. HIA identifies how a particular decision will alter these “social determinants” of health and assesses the likely impact on the health of different groups in a population.

The NHS cannot be the sole agency responsible for our health and well being. Integrated decision making is needed to address the complex and multiple effects of policies, programmes and projects, and should be central to any national and local strategy to improve health and tackle inequalities. In Wales the consequences of industrial decline have left an unwelcome legacy in terms of long term physical and mental ill-health, and early death. HIA can ensure that concerns about health and well being cut across strategies for regenerating the most deprived areas in the country.

The benefits of HIA

The benefits of HIA can include:

  • promotion of greater equity in health
  • action to maximise health and well-being benefits and minimise health and well being risks
  • increased awareness amongst policy and decision makers across sectors of how decisions may affect health
  • identifying the connections between health and well being and other policy areas
  • promotion of evidence and knowledge-based planning and decision making
  • potential to reduce demand on NHS and social care services by investing in healthy policies, programmes and projects that prevent ill health.

HIA in Welsh Government Policy

Health Impact Assessment has had strong support from the Welsh Government from the early days of the Welsh Assembly. In 1998 Better Health, Better Wales proposed HIA as an important strand in the development of public health policy in Wales and the Welsh Government went on to fund the establishment of a Wales Health Impact Assessment Support Unit from 2001 to develop the capacity of local government and other organisations to undertake HIA in Wales. 

Over the past ten years HIA has become integrated into a number of areas of planning policy in Wales (See table below). Planning Policy Wales guidance on Local Development Plans also states that “The several impacts of plans upon health and its determinants should be considered (p21)”. A significant number of Local Authorities in Wales have used HIA as an integrated part of developing their recent round of Local Development Plans.

More recently the Welsh Government “Together for Mental Health” Delivery Plan 2012-16 has stated an intention to “increase the number of impact assessments that include mental wellbeing”.

Guidance Document


Welsh Transport Appraisal Guidance (WelTAG) (2008)

Screening for HIA a mandatory requirement

Minerals Technical Advice Note (MTAN) 2: Coal (2009)

HIA to be included as part of EIA (where significant effects on human health may occur)

Ministerial Interim Minerals Planning Policy Statement (MIMPPS) (2009)

HIA required for all planning applications for opencast coal mining in Wales

Technical Advice Note (TAN) 21: Waste (2014)

Recognises HIA as a valuable tool to identify health and well-being concerns

On this topic page, and through the pages and links leading from it, you will find out more about how HIA is being used in Wales and also find a wealth of case studies, guidance and evidence to support you to use HIA and to share best practice.

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What About Health?

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Worldwide, 13 million deaths could be prevented every year by making our environments healthier.
10 facts on preventing disease through healthy environments, WHO

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