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Health Impact Assessment (HIA) - Frequently Asked Questions (FAQ)

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What are Health Impacts?

Health impacts are both direct and indirect effects associated with a policy, project, or program on the health of an affected population. In other words, health impacts are both positive and negative effects on the people that are living and working in the community or communities influenced by a particular policy, project or program. Some health impacts are felt immediately, and others may not be felt for a longer period of time.

What is a Health Impact Assessment?

The HIA 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” (Gothenburg Consensus). In other words, the HIA is a toolbox that public health planners and researchers use to see what sort of health effects may occur in a community or neighborhood where a project or policy takes.

What is the purpose of an HIA?

According to the Gothenburg Consensus paper, the purpose of a HIA is to “Improve knowledge about the potential impact of a policy or programme, inform decision-makers and affected people, and facilitate adjustment of the proposed policy in order to mitigate the negative and maximize the positive impacts.”

Why does the HIA matter?

According to Waldo Tobler, the First Law of Geography is “everything is related to everything else, but near things are more related than distant things.” When a new project or policy is brought about in a neighborhood or community, it will have direct effects on the people who live and work there. It is important to understand what sort of impact the policy or project will have on the people who live there, and the HIA is a tool that helps planners, decision-makers and community members understand how the project or policy might affect the health of the people who live in the community or neighborhood. When decision-makers, planners, and community members understand what the effects of the project or policy will be, it helps them to make informed decisions about how to increase the benefits and lessen the negative impacts the project or policy could have on the community.

What Values are important in an HIA?

The World Health Organization outlines four core values at the heart of every good HIA:

1. Democracy – the HIA allows people to have a voice in projects, programs, and policies that will directly and indirectly affect their lives and their community
2. Equity – the HIA assesses how impacts are spread out among the people in a community; the HIA pays particular attention to how impacts could affect vulnerable people, such as children, seniors, minorities, and those in poverty.
3. Sustainable Development – the HIA studies both the short- and long-term impacts of a project or policy. The HIA should be designed to look for the less-obvious impacts as well as the obvious impacts.
4. Ethical Use of Evidence – The HIA should collect a wide variety of quantitative and qualitative evidence and use the best methods available to use that evidence in the study.

What are the steps in a HIA?

The United States Centers for Disease Control (CDC) outlines the major steps in a HIA as follows:

1. Screening – identify projects or policies for which an HIA would be useful;
2. Scoping – identify which health effects to consider;
3. Assessing Risks and Benefits – identify which people may be affected and how they may be affected;
4. Developing Recommendations – suggest changes to proposals to promote positive or mitigate adverse health effects;
5. Reporting – present the results to decision-makers; and
6. Evaluating – determine the affect of the HIA on the decision process.

Who can use a HIA?

A HIA can be used by:

- decision-makers who want to make informed choices to benefit public health;
- HIA workers and planners, including private consultants, public health staff and officials, community organizations, and volunteers; and
- stakeholders who want to know how the project or policy will affect themselves and their community, business and neighborhood.

Where have HIAs been used?

The World Health Organization maintains a list of countries that utilize HIAs in planning and development. A partial list of these countries include: Australia, Canada, Sweden, Switzerland, the United Kingdom, the Netherlands, and the United States.

The UCLA HIA Clearinghouse Learning and Information Center (HIA-CLIC) maintains a database of completed HIAs in the United States. Some examples of completed HIAs include:

- Humboldt County General Plan Update (Humboldt County, CA – March 2008)
- Santa Monica Airport HIA (Santa Monica, CA - February 2010)
- Crossings at 29th ST/San Pedro Streets (Los Angeles, CA – August 2009)
- Red Line Transit Project (Baltimore, MD – December 2008)
- National Petroleum Reserve (Alaska – September 2008)

Where can I find an example of an HIA?

The UCLA HIA-CLIC (mentioned above) has links to dozens of HIAs conducted in the United States. The HumPAL website contains the Humboldt County GPU HIA and supporting documents, which is available at