GEneral information
Health Impact Assessment
Definition
Health is “a state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity” (World Health Organization, 1946).
Overview of Health Impact Assessment
Health Impact Assessment (HIA) is defined as “a process which systematically judges the potential, and sometimes unintended, effects of a project, program, plan, policy, or strategy on the health of a population and the distribution of those effects within the population. HIA generates evidence for appropriate actions to avoid or mitigate health risks and promote health opportunities. HIA guides the establishment of a framework for monitoring and evaluating changes in health as part of performance management and sustainable development” (IAIA Best Practice Principles, Health Impact Assessment, 2021).
Good population health is not just of intrinsic value but is also cost saving for society and governments. HIA supports policy makers to understand the population health effects of their decisions. HIA provides evidence-based insight into complex health pathways and trade-offs.
HIA is used to improve population health and reduce health inequalities through more informed decision making. HIA can be applied to decisions about new legislation, strategies, policies, plans or projects. Often the most effective and resource efficient HIAs are those that are undertaken at the strategic decision-making stage, e.g. to shape new legislation or policies.
Triggers for undertaking HIA include financial lending criteria, legal obligations, policy requirements and voluntary practice. Establishing national institutionalized HIA triggers is a key HIA capacity building activity.
Key features of HIAs are that they: consider a broad range of influences on population health (wider determinants of health); support delivery of sustainable development; center around those people affected by a decision (participation); identify if some population groups are more affected and if that is fair (equality and equity); and take an approach that is transparent and rigorous in the sources of evidence used (ethical use of evidence). HIA considers both physical and mental health outcomes.
Key outcomes a HIA can promote to improve population health include: narrowing health inequalities; promoting healthy lifestyles; promoting safe and cohesive communities; enhancing socio-economic conditions to enable people to thrive; enhancing environmental conditions; and improving access to good-quality health and social care.
HIA Procedures
HIA is intended to produce a set of evidence-informed recommendations to guide decision-making. It seeks to maximize the positive health impacts and mitigate 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, including environmental impact assessment and social impact assessment. HIA is generally described as following these steps, though practitioners may use different labels or break them into sub-steps:
- Screening – Determining if an HIA is warranted or required.
- Scoping – Defining which health impacts will be considered and planning the HIA process.
- Impact Assessment – Systematically assessing the nature, likelihood and significance of potential positive and negative health impacts.
- Reporting – Providing a description of the method applied, any constraints encountered, the population health effects identified, and the mitigation or enhancement measures.
- Implementation and Monitoring – The activity of implementing the mitigation and enhancement measures, as well as undertaking any proportionate monitoring.
The primary objective of HIA is to apply existing knowledge and scientific evidence about health impacts to specific social and community contexts, developing recommendations that support decision-making. The goal is to protect and enhance community health and well-being.
Past HIAs, particularly those that have been monitored and evaluated over time, provide valuable insights for future assessments.
An HIA’s recommendations may address a proposal’s options or alternatives, as well as its design or management across its phases (e.g. construction, operation and decommissioning).
History of HIA
The use of HIA has evolved from three key origins:
- HIA as an extension of environmental impact assessment – Initially, health considerations were incorporated within broader environmental assessments, later leading to dedicated HIA processes.
- HIA as a framework for intersectoral action on the broader determinants of health – Recognizing that health outcomes are shaped by factors beyond healthcare, HIA became a mechanism to address social, economic, and environmental influences on health.
- HIA as a strategy to reduce and address health inequities – HIA has been increasingly used to assess how policies and projects may disproportionately affect vulnerable populations, promoting health equity.
Figure 1: Selective timeline of the development of Health Impact Assessment (Source: Harris-Roxas & Harris, 2010)
HIA Around the World
HIA is widely used and continues to evolve globally, particularly in Europe, North America, Australia, New Zealand, and parts of Asia, including Thailand.
Numerous approaches and models for Health Impact Assessment have been developed internationally. Many of these models and guidelines have been shaped by country- or region-specific regulatory and policy frameworks. The focus of government agencies, international organizations, and multidisciplinary research influences these guidelines and models. As a result, HIA is treated as a standalone process in some regions while being fully integrated with other forms of impact assessment in others.
The Performance Standards of the International Finance Corporation (IFC), part of the World Bank Group, were updated in 2012 and include requirements for assessing health impacts in large-scale project proposals. These standards are widely recognized by leading financial institutions that adhere to the Equator Principles, which promote responsible environmental and social risk management.
Health Impact Assessments are increasingly applied in large-scale development projects across both the public and private sectors, particularly in low- and middle-income countries. HIA also has a long history in water resource development, especially in the planning of large
Health Section at IAIA
IAIA Sections provide opportunities for IAIA members with mutual interests to share experiences and discuss ideas in an informal setting. Sections provide a forum for active topical debate and for development and promotion of good practice. Sections network, communicate, and share resources in IAIA’s online community, the “IAIA Hub”.
IAIA’s Health Section addresses HIA throughout the world and the integration of human health concerns into impact assessment. Current IAIA members can join the Health Section group in the IAIA Hub to get involved.
Key publications by the Health Section include:
- Health Impact Assessment International Best Practice Principles (2021)
- FasTips No. 8: Health Impact Assessment
- Human Health: Ensuring a High Level of Protection. A Reference Paper on Addressing Human Health in Environmental Impact Assessment
- Key Citations Series: Health Impact Assessment
Find these (and more!) in the IAIA Resource Library.
