An Introduction to Health Impact Assessments

Health Impact Assessments (HIAs) are assessment tools to evaluate potential health effects—both positive and negative—of proposed policies, programs, or projects. While HIAs can be conducted at the local, state, or national level, they are most commonly applied in local and regional contexts where decisions about land use, transportation, and community planning directly impact public health. By providing decision-makers with critical data and insights, HIAs guide community actions and influence policies that can shape long-term health outcomes. For example, an HIA conducted on the Lower Duwamish Superfund site in King County, Washington, influenced cleanup efforts, ultimately reducing environmental hazards and improving community health. The assessment highlighted the need for a 17-year cleanup plan that addresses both environmental and socio-economic challenges, ensuring long-term health protections for local residents, especially those dependent on the river for subsistence.

HIAs offer benefits across sectors by providing a structured process to evaluate health impacts and guide policies, plans, and investments. This is important because community health and well-being are impacted by all community initiatives, even when the work is not implicitly “health-related”. There is opportunity for improving (and worsening) well-being through any community investment, so it’s important to assess the potential health impact of a proposed investment or policy before moving forward.

In addition to fostering cross-sector collaboration, HIAs can promote community engagement and build trust through public forums or stakeholder meetings to review HIA results and discuss implications. By expanding access to health-promoting resources like healthy foods, transit, and health care, HIAs help protect priority populations from disproportionate exposure to negative upstream impacts and environmental hazards. HIAs achieve this by identifying areas of need and disparity, advocating for policy changes, and ensuring that resources are distributed equitably. These assessments can ensure resources are leveraged for the greatest impact and drive immediate and long-term improvements in health, well-being, and equity.

HIA Process

HIA is a structured, yet flexible, process by which to consider the health implications of a policy, plan, or investment and how those impacts might disproportionately affect different racial, income, geographic, and other population groups. HIAs employ various methods—bringing together qualitative and quantitative data, public health expertise, and stakeholder input—to judge potential health effects and provide recommendations for enhancing health benefits and minimizing risks or harms.

The process is summarized in six steps.

1. Screening: Determines the necessity and feasibility of conducting an HIA. 
2. Scoping: Identifies the health impacts to be assessed and the affected population groups.
3. Assessment: Uses qualitative and quantitative data, along with stakeholder input, to analyze potential health effects.
4. Recommendations: Offers strategies to enhance health benefits and minimize risks.
5. Reporting: Communicate findings to decision-makers and stakeholders to guide policy or project decisions.
6. Monitoring and Evaluation: Tracks implementation and evaluates the outcomes of recommendations.

Types of HIAs

HIAs differ in intensity, timeline, team, and budget required. Types of HIAs are summarized below.

Type	Description	Team Size	Time Frame
Desktop	Relies mainly or exclusively on existing research and remote contact with stakeholders	1-2 team members	2-6 weeks
Rapid	Uses a shortened approach to an HIA, with a smaller amount of primary research and stakeholder engagement	1-2+ team members	Up to 3 months
Intermediate	May involve a workshop with stakeholders in addition to desktop and rapid assessment techniques	Varies	Varies
Comprehensive	Uses as much evidence as possible, including an extensive search of literature and other existing information, in-depth interviews, community surveys, some original research if appropriate, and input from experts and agencies	May require a team	Up to 6+ months

HIAs in Decision-Making

HIA is a powerful tool for centering community health and well-being in public decision-making and advancing evidence-informed public policy and a Health in All Policies approach. HIAs help decision-makers craft smarter policies that protect health, facilitate collaboration, engage stakeholders and the public, and integrate health concerns into policy decisions.

For example, when a local or state government is considering adopting a particular policy or investing in new infrastructure, an HIA arms decision-makers and stakeholders with evidence about how the policy or project will affect community health and provides recommendations for improving health and minimizing negative health impacts. In this respect, HIAs promote better-informed decisions and, when acted upon, produce better health and well-being outcomes.

HIA Applications Across Sectors

HIAs help advance goals for cross-sector collaboration for health. They are applied across sectors to inform decision-making; examples are noted below.

Planning

• Assess health impacts of land use, transportation, zoning, and infrastructure decisions
• Support data-driven strategies
• Foster cross-sector collaboration
• Enhance public engagement

Housing

• Guiding policies on affordable housing, housing quality, and neighborhood conditions
• Address factors like indoor air quality, transportation access, and socioeconomic disparities

Education

• Inform decisions on school policies, early childhood programs, and student transportation
• Improve learning environments and student well-being

Employment

• Support workforce development strategies, wage policies, and paid leave regulations
• Promote economic stability and health equity

Climate Resilience

• Guiding climate mitigation strategies and resilience planning
• Support the adoption of sustainable energy alternatives to protect community health

Economic Development

• Inform revitalization efforts and business growth strategies
• Guide investments in infrastructure to enhance local economies and community well-being

Explore HIAs in these and other sectors at the Health Impact Assessment Space on Community Commons

Health Impact Assessments (HIAs) are more than tools for evaluating health impacts—they are catalysts for informed decision-making and shared stewardship. By equipping decision-makers with actionable insights, HIAs empower leaders, organizations, and communities to shape policies that promote health equity and improve well-being. When thoughtfully applied, HIAs strengthen collaboration, elevate community voices, and create lasting positive change in the systems that shape our daily lives.

The HIA Space on Community Commons simplifies researching existing HIAs so policymakers and community organizers can maximize resources by building on others’ work and move more quickly into implementation. Learn more here!