Health Impact Assessment (HIA)

Why use HIA?

Reasons to use HIA

Promotes cross-sectoral working

The health and well-being of people is determined by a wide range of economic, social and environmental influences. Activities in many sectors beyond the health sector influence these determinants of health. HIA is a participatory approach that helps people from multiple sectors to work together. HIA participants consider the impacts of the proposed action on their individual sector, and other sectors – and the potential impact on health from any change. Overlaps with other policy and project initiatives are often identified, providing a more integrated approach to policy making. "Joined up thinking" and "cross-sectoral working" are phrases that apply to the HIA way of working.

A participatory approach that values the views of the community

An initial stage within the HIA process is to identify the relevant stakeholders. This process usually produces a large number of relevant people, groups and organizations. The HIA can be used as a framework to implicate stakeholders in a meaningful way, allowing their messages to be heard.

Stakeholders commonly include:

  • The local community/public, particularly vulnerable groups
  • Developers
  • Planners
  • Local/national governments
  • Voluntary agencies, nongovernmental organizations
  • Health workers at local, national or international levels
  • Employers and unions
  • Representatives of other sectors affected by the proposal
  • The commissioner(s) of the HIA
  • The decision-makers
  • The network of people and organisations who will carry out the HIA.

HIA provides a way to engage with members of the public affected by a particular proposal. An HIA can send a signal that an organization or partnership wants to involve a community and is willing to respond constructively to their concerns. Because the HIA process values many different types of evidence during the assessment of a proposal, the views of the public can be considered alongside expert opinion and scientific data, with each source of information being valued equally within the HIA. It is important to note that the decision makers may value certain types of evidence more than others, and community expectations must be managed to avoid ‘over-promising what an HIA can deliver. An HIA does not make decisions; it provides information in a clear and transparent way for decision makers’.

The best available evidence is provided to decision-makers

The purpose of an HIA is to provide decision-makers with a set of evidence-based recommendations about the proposal. The decision-makers can then decide to accept, reject or amend the proposal, in the knowledge that they have the best available evidence before them. Evidence used in an HIA can be both qualitative and quantitative, and each is valuable. HIA should consider a range of different types of evidence – going beyond published reviews and research papers, to include the views and opinions of key players who are involved or affected by a proposal. Often, information of the quality and quantity demanded by decision-makers cannot be found, a note of this is made within the HIA and the best available evidence is provided.

Improves health and reduces inequalities

Addressing inequalities and improving health is a goal for many organisations and all governments. One way of contributing to the health and inequalities agenda is through the use of HIA. At the very least, HIA ensures that proposals do not inadvertently damage health or reinforce inequalities. HIA uses a wide model of health and works across sectors to provide a systematic approach for assessing how the proposal affects a population, with particular emphasis on the distribution of effects between different subgroups within the population. Recommendations can specifically target the improvement of health for vulnerable groups.

It is a positive approach

HIA looks not only for negative impacts (to prevent or reduce them), but also for impacts favourable to health. This provides decision-makers with options to strengthen and extend the positive features of a proposal, with a view to improving the health of the population.

Appropriate for policies, programmes and projects

HIA is suitable for use at many different levels. HIA can be used on projects, programmes (groupings of projects) and policies, though it has most commonly been used on projects. The flexibility of HIA allows these projects, programmes and policies to be assessed at either a local, regional, national or international level – making HIA suitable for almost any proposal. However, choosing the right moment to carry out an HIA is important (see screening).


To influence the decision-making process, HIA recommendations must reach the decision-makers well before any decisions about the proposal will be made. This basic principle of HIA highlights the practical nature of the approach. Experienced HIA practitioners can work within most timeframes, undertaking comprehensive (longer) or rapid (shorter) HIAs.

Links with sustainable development and resource management

If the HIA is undertaken at a sufficiently early stage in the project process, it can be used as a key tool for sustainable development. For example, an HIA on building a road would enable inclusion of health and other sustainability aspects - such as cycle lanes, noise and speed reduction interventions - to be included from the very beginning, rather than at a later date. This enables health objectives to be considered at the same level as socio-economic and environmental objectives, an important step towards sustainable development. Another feature of HIA is its possible combination with other impact assessment methods. This integration allows proposals to be assessed from a sustainable development perspective including: health, education, employment, business success, safety and security, culture, leisure and recreation, and the environment. Drawing on the wider determinants of health, and working across different sectors, HIA can play an important role in the sustainability agenda.

Many people can use HIA

Because it is a participatory approach, there are many potential users of HIA, including:

  • Decision-makers who may use the information to select options more favourable to health;
  • Commissioners of the HIA, who use it to consult widely and gather differing views, to build capacity and develop strong partnerships;
  • HIA workers who carry out the individual components of the HIA, including consultants, local staff from a wide variety of organizations, and the community;
  • Stakeholders, who want their views to be considered by decision-makers.