EJI Frequently Asked Questions (FAQ)

General

The EJI can be used to

identify and prioritize areas that may require special attention or additional action to improve health and health equity,
educate and inform the public about their community,
analyze the unique, local factors driving cumulative impacts on health to inform policy and decision-making, and
establish meaningful goals and measure progress towards environmental justice and health equity.

Researchers can use data from the EJI to generate hypotheses. For example, researchers might want to determine whether social vulnerability or environmental burden are associated with overall life expectancy at the census tract level. Please see the section below entitled “Using the Data” if you are using the EJI for secondary analysis.

A community organization can use the EJI to display information about the community to educate others. The organization might compare scores for several neighborhoods, highlighting those that need additional resources to address environmental burden or social determinants of health.

The graphic below shows the modules, domains, and indicators included in the CDC/ATSDR EJI.

Health vulnerability measures are marked with asterisks because they are calculated differently than other indicators. While most indicators can have a range of values, the health vulnerability indicators represent only whether a given census tract experiences a high estimated prevalence of disease or not. See the technical documentation for more information on indicators and index scoring.

EJI Indicators

Text-Only Version

Social vulnerability module

Racial/Ethnic Minority Status
- Minority Status
Socioeconomic Status
- Poverty
- No High School Diploma
- Unemployment
- Housing Tenure
- Housing Burdened Lower-Income Households
- Lack of Health Insurance
- Lack of Broadband Access
Household Characteristics
- Age 65 and Older
- Age 17 and Younger
- Civilian with a Disability
- Speaks English “Less than Well”
Housing Type
- Group Quarters
- Mobile Homes

Environmental burden module

Air Pollution
- Ozone
- PM2.5
- Diesel Particulate Matter
- Air Toxics Cancer Risk
Potentially Hazardous and Toxic Sites
- National Priority List Sites
- Toxic Release Inventory Sites
- Treatment, Storage, and Disposal Sites
- Risk Management Plan Sites
- Coal Mines
- Lead Mines
Built Environment
- Recreational Parks
- Houses Built Pre-1980
- Walkability
Transportation Infrastructure
- High-Volume Roads
- Railways
- Airports
Water Pollution
- Impaired Surface Water

Health vulnerability module

Pre-existing Chronic Disease Burden
- Asthma*
- Cancer*
- High Blood Pressure*
- Diabetes*
- Poor Mental Health*

We plan to update the EJI periodically with the release of new data from three of the data sources (the U.S. Census Bureau, the U.S. Environmental Protection Agency, and the Centers for Disease Control and Prevention).

Centers for Disease Control and Prevention and Agency for Toxic Substances Disease Registry. 2022 Environmental Justice Index. Accessed [Date]. https://www.atsdr.cdc.gov/placeandhealth/eji/index.html

Methodology

We are developing a manuscript that outlines the creation and validation of the index. Until this manuscript is published, please refer to the EJI Technical Documentation for information on index methods.

Details on indicator selection and evaluation can be found in the EJI Technical Documentation.

Definitions of the indicators can be found on the EJI Indicators page.
Additional data documentation can be found in the EJI Technical Documentation.

We did not weight the indicators in the EJI because it’s a standard tool that’s national in scope, and the importance of specific EJI indicators may vary by community. Local expertise is essential for identifying environmental justice issues at the community level, and determining which indicators are most appropriate. Users of the tool can weight and customize their data depending on community needs.

Data for some environmental indicators are not collected for Alaska and Hawaii, so the EJI scores for these states are not currently available.

Data for Puerto Rico, Guam, American Samoa, the U.S. Virgin Islands, and the Northern Mariana Islands are unavailable or not collected at the level needed for inclusion in the EJI.

We plan to add climate indicators in future versions of the EJI.

Using the Data

A percentile ranking represents the proportion of tracts (or counties) that are equal to or lower than a tract of interest in environmental burden. For example, a EJI ranking of 0.85 signifies that 85% of tracts in the nation likely experience less severe cumulative impacts from environmental burden than the tract of interest, and that 15% of tracts in the nation likely experience more severe cumulative impacts from environmental burden.

Not exactly. The census data used in the EJI are available at the census tract and county levels, but not at the ZIP code level. This is because ZIP codes are postal delivery areas, and their borders are subject to change by the postal service. Anyone interested in using data at the ZIP code level may benefit from using HUD USPS ZIP Code Crosswalk Files.

U.S. Census Bureau ZCTAs are relatively stable representations of ZIP codes for a snapshot in time, however neither ZIP codes nor ZCTAs are designed for comparison across long stretches of time, as census tracts are designed to do.

Although this is mathematically possible, we do not recommend it. Aggregation introduces unmeasurable error and could misrepresent neighborhood-level variation in social, environmental, and health conditions.

The EJI Social-Environmental Ranking (SER) is calculated by combining rankings from the Environmental Burden Module and the Social Vulnerability Module, but not from the Health Vulnerability Module.

The Social-Environmental Ranking represents a measure of distributive and participatory environmental justice factors that may influence human health and well-being. The Social-Environmental Ranking is more suitable than the full EJI for research and secondary analyses where health outcomes are of interest (see below).

The Social-Environmental Ranking can also be used alongside the High Prevalence Flags (see below) for an overview of how specific health outcomes may be related to distributive and participatory environmental justice. For more information on the Social-Environmental Ranking and how it differs from the overall EJI, please see the EJI Technical Documentation.

Disease prevalence flags inform whether an area is high in estimated prevalence for individual diseases. High estimated prevalence is defined as the top 33.33% of all U.S. census tracts.

Flags can be used alongside the Social-Environmental Ranking to inform whether areas that experience high levels of cumulative environmental burden and social vulnerability also experience high levels of disease burden. For example, if a user is interested in seeing how asthma rates compare to cumulative impacts from environmental and social factors for a given community, then the user should not use the full EJI because asthma is already included as an indicator and would skew the comparison. Instead, the user can overlay asthma flags on a Social-Environmental Ranking map to see where environmental burden, social vulnerability, and asthma rates align. More information on disease prevalence flags can be found in the EJI Technical Documentation.

Disease prevalence flags inform whether an area is high in estimated prevalence for individual diseases. High estimated prevalence is defined as the top 33.33% of all U.S. census tracts.

The EJI is intended as a high-level mapping and screening tool that characterizes cumulative impacts and patterns of environmental injustice across the U.S. The tool relies on historical data generated by various institutions on varying time scales.

The EJI is not intended as

a definitive tool for labeling environmental justice communities,
a tool for characterizing all environmental justice issues,
a comprehensive representation of current or future social, environmental, or health characteristics,
a representation of risk or exposure for a community, or
a tool to tell whether individuals are at risk.

Complete information on limitations of the EJI can be found in the technical documentation.

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For more information, contact the EJI Coordinator at eji_coordinator@cdc.gov.

Media inquiries may be sent to placeandhealth@cdc.gov.