Health Impact Assessment

Why Conduct an HIA

Health Impact Assessment

What is a Health Impact Assessment?

Health Impact Assessment (HIA) is a process that helps evaluate the potential health impacts of a proposed project, plan, or policy before it is approved, built, or implemented. HIA aims to inform decision makers about the potential health impacts of a decision and provide recommendations to increase positive health outcomes and minimize adverse health outcomes. The process is particularly useful in non-health sector decisions, such as transportation and land use. (

Do You Need a HIA? 

HIA is best utilized when a specific decision is being made. It serves to inform decision makers on the potential health impacts of the policy, plan, or project. To learn more about HIAs completed in Texas and across other states, visit the PEW Charitable Trust’s Health Impact Project Toolkit

Why Conduct a HIA? 

HIA has a multitude of benefits beyond informing decision makers with a rigorous, data-driven assessment of health-related impacts. For Harris County Public Health, HIA process helps accomplish a number of goals:

  • Develops a deep understanding of health issues from local knowledge and expert opinions 
  • Establishes networks and pathways to better mobilize stakeholders (e.g., community-based organizations and local government) and community members around collective actions to address common barriers to healthy communities 
  • Effects change with upstream health issues (social determinants of health) in order to impact long-term population health outcomes

Types of HIAs

There are many approaches to using HIA. These approaches are outlined below and can help you determine what type of process may work for you.


As the name implies, this HIA focuses mainly on existing research and remote contact with a few stakeholders. It would probably be carried out by one or two people and may take between two to six weeks.


A rapid HIA uses both existing research and rapid assessment techniques, so it includes some fieldwork. Although it could be carried out by one or two researchers, it may also involve more and can take up to three months.2 

See the Rapid HIA Toolkit from London for additional guidance.


An intermediate HIA may combine a workshop with key stakeholders followed by desk-based work to build up a more detailed picture of the potential health impacts than would typically be identified during a rapid or "mini" HIA. It may involve a limited literature search, usually non-systematic, and relies mainly on surveillance or routine, readily available data.


A comprehensive HIA examines as much evidence as possible, using: 

  • An extensive search of the literature and other existing information 
  • In-depth interviews 
  • Community surveys 
  • Some original research if appropriate 
  • Input from experts and agencies 

This type of HIA can take six months or more and can require a team to conduct it. 

See Minimum Elements and Practice Standards for Health Impact Assessment published by the North American HIA Practice Standards Working Group.

Additional Resources

Conducting an HIA

The resources below provide guidance for conducting health impact assessments. They highlight the 6-step process and explain in detail the methodology for assessing evidence.

  • HIA process
  • Assessing the evidence base
Community Engagement

Community engagement is an instrumental element throughout the phases of HIA. Effective community engagement is key to ensuring all voices are heard during the decision-making process, especially in communities and populations who are more likely to be adversely impacted by the changes being proposed. By engaging the community, an open dialogue is developed to gain a comprehensive perspective of health issues and their root causes. Community involvement builds consensus and provides a platform for the community to engage in the decision-making processes that affect their health and overall well-being. 

Engagement methods can be drawn from a number of disciplines. Below are a number of helpful resources to determine a successful community engagement approach for an HIA.

HIA Case Studies

The Harris County Public Health Built Environment (HCPH BE) Unit conducts Health Impact Assessments (HIAs) and Health Impact Reviews (HIRs) to examine and lessen health risk through policy, planning, and development decisions in the Houston-Harris County region. For completed HIAs, see below. 

East Aldine Districts’ Town Center Development 

This HIA was performed on the development and design of the East Aldine Management District’s proposed town center. It focused on how the town center will affect mobility and connectivity in the area. 

Healthy Planning in Pasadena, Texas 

In partnership with the City of Pasadena Planning Department, HCPH conducted a HIA on proposed updates to city residential ordinances. It focused on how changes in city ordinances and community design could impact the health of the community. 

Other Completed HIAs 

Additional completed HIAs can be found at The PEW Charitable Trusts and Robert Wood Johnson Foundation, Health Impact Project.

Funding Resources

The Built Environment team will work with partners to determine the amount of funding needed to conduct a HIA or HIR. If the process timeframe permits additional use of tools or the use of subject matter experts then funding will likely be required. There are a number of grant opportunities available related to improving the built environment and conducting health assessments. 

Summarized below is a non-comprehensive list of organizations that historically support built environment and health initiatives.