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Health Impact Assessment Data Guide

Health Impact Assessment Data Guide

This guide provides suggestions for how to use data from the Tracking Network in an HIA. Users who are new to HIA practices are encouraged to seek background information about HIAs here.

Tracking data may be used to inform any of the six steps for conducting an HIA, but this guide focuses on three specific steps:

  • Scoping – to explore health and environment issues of potential interest to a community or when conducting an HIA
  • Assessment – to assess a baseline for conditions, refine priorities, inform communities, or make projections or estimates about trends
  • Monitoring and Evaluation – to evaluate the effects of a decision, policy, or action over time; pre- and post-implementation


When conducting HIAs, scoping is a process that defines what the assessment will address, including geographic and time boundaries, health issues, people potentially affected, and data sources. Scoping helps create a viable work plan and timeline. This step is usually informed by the concerns identified during the stakeholder engagement process, from professional or expert opinions, and by relevant literature.

For more information about engaging stakeholders, see Guidance and Best Practices for Stakeholder Participation in Health Impact Assessments: Version 1.0. For more information about conducting HIAs, see CDC's Healthy Places Health Impact Assessment website.

The Tracking Network can be useful for two specific parts of the scoping step:

  • Pathway Diagrams: A central task of the scoping step is determining how the decision or project can impact health. You can facilitate this by developing pathway diagrams which illustrate the steps from decision to health outcome. Pathway diagrams help identify health effects and benefits. Tracking Network data can be used to assess these effects by providing baseline information about health status in a community or by predicting effects and benefits from a policy, plan, or project. See examples of how Tracking data can be used in three different health impact assessments.
  • Identifying questions and data: Another key task of the scoping step is identifying the research questions, data sources, and analytic methods that will be used. The Tracking Network can be a source of data for this step. See an example of an HIA scoping worksheetfrom Human Impact Partners.


In this step of an HIA, Tracking Network data may be used to evaluate the health effects and benefits of a plan, project, program, or policy by:

  • Assessing baseline health conditions
  • Identifying and characterizing vulnerable populations, health disparities, and health inequities
  • Evaluating the direction and magnitude of potential health effects due to changes in exposure or actions to protect health

For example, HIA practitioners and communities may want to know more about asthma in a particular area. The National Tracking Network can provide data about asthma hospitalizations and emergency department visits at state and county levels to establish a baseline health estimate and provide information on geographic areas within the region of interest. State and local tracking programs also may have asthma data at different levels of geography, such as ZIP code.

The assessment step in the HIA process also may include projections to evaluate the direction and magnitude of potential health effects due to changes in exposure or actions to protect health. Tracking data may be used in quantitative or qualitative assessments to make informed projections based on trends over time.

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Monitoring and Evaluation

Tracking Network data are updated on an ongoing basis. This makes Tracking Network data especially useful for monitoring and evaluating actions and decisions over time. For example, Tracking data can be used to evaluate progress pre- and post-implementation of the HIA decision or action. Furthermore, Tracking Network data are developed to be nationally consistent which helps compare one area or population with another.

Tools and Resources for Data Users

Consultation and Expertise

The Tracking Program includes CDC staff and public health department staff in 23 states and 1 large city with expertise in several areas:

  • Data analysis and interpretation
  • Data visualization (charts, maps/GIS)
  • Communication message development and risk communication

HIA practitioners who have questions about tracking data, or need technical assistance, may contact CDC's National Tracking Program or the state and local tracking programs.

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Data Analysis and Tools

  1. Geographic Information Systems (GIS) are useful tools for analyzing and visualizing results for a proposed HIA. GIS maps can:
    • show geographic boundaries of the area of interest
    • identify and determine accessibility to community attributes (e.g., green space, recreational areas, stores, public services)
    • present health, demographic, and environmental data at different geographical scales within the project area (i.e., census tract, zip code, or community level)
    • use spatial interpolation tools (e.g., ESRI's ArcGIS Spatial Analyst or Epi-Info).

    CDC's National Tracking Network and the state and local grantee networks offer dynamic mapping capabilities for most of the data available in the surveillance systems. You can view data with a number of different mapping options and request technical assistance with mapping if needed.

  2. Attributable risk estimates may be used to quantify rates of death and illness associated with changes in exposure. These types of estimates can be made using the US EPA Environmental Benefits Mapping and Analysis Program (BenMAP). This is a free program that applies concentration-response functions from published studies to estimate changes in the burden of health effects associated with changes in air temperature or quality. For example, see Mortality Benefits Associated with Reducing PM2.5(fine particle) Concentration Levels. You can generate data from the Tracking Network that provides the estimated number of deaths prevented and percent change in deaths associated with lowering PM2.5concentration levels in air. BenMAP does not have the same spatial analysis capabilities as GIS, but it can be useful for contributing to attributable risk estimates.
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Additional Resources

For additional information about conducting HIAs and using the Tracking Network for HIAs, visit the additional resources section of this webpage. You will find success stories, case studies, and videos. Also, seeTools and Resources from Human Impact Partners.

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