About the Food Desert Locator

About the Food Desert Locator

• Overview
• Background
• Objectives
• How is a food desert defined?
• What can users do with the Locator?
• How is the Food Desert Locator related to the Food Environment Atlas?
• Press Kit

Overview

Part of the First Lady's Let's Move! initiative, the proposed Healthy Food Financing Initiative (HFFI) will expand the availability of nutritious food to food deserts—low-income communities without ready access to healthy and affordable food—by developing and equipping grocery stores, small retailers, corner stores, and farmers markets with fresh and healthy food. The HFFI is a partnership between the Treasury Department, Health and Human Services, and the Agriculture Department (USDA). An Interagency Working Group from the three departments, along with staff from the Economic Research Service (ERS/USDA), developed a definition of food deserts to be used with other data to determine eligibility for Federal funds.

Background

In a 2009 report to Congress, Access to Affordable and Nutritious Food: Measuring and Understanding Food Deserts and Their Consequences, ERS outlined a number of ways to measure how many people have limited access to food and how many live in low-income areas with limited access. The report used 1-kilometer (km) square grids as the base geographic unit of analysis, measuring distance from the nearest source of healthy foods. Grids outside of a specified distance from a food source were designated as low access areas (separate markers for low access were used for rural and urban areas). Grids with high concentrations of low-income individuals received particular attention.

Supermarkets and large grocery stores were used as proxies for sources of healthy and affordable foods. Based upon these data sources and measures, the report described characteristics of people and households residing in areas with limited access to healthy and affordable food such as the number of poor people, the number of children or older persons, and the number of households without vehicles.

The definitions and methods used in the 2009 ERS report provide accurate and credible estimates of the extent of limited access to healthy food in the U.S. population across a large and geographically diverse country. Use of the 1-km square grid increased precision in measuring where people are and how far they are from sources of healthy food; the 1-km square grid measure also provided consistency in defining geographic areas across the country. However, the 1-km square grids are not widely used geographic units; organizations and communities applying for HFFI funding are unlikely to be familiar with them; and there is no standardized way to identify a specific grid (unlike counties, zip codes, or census tracts which can be identified).

Because of unfamiliarity with these grids, the HFFI working group decided to use census tracts as the geographic units of analysis. Census tracts are more commonly used geographic measures and have a standardized numbering system. (The 1 kilometer-square grids are still used to measure distance as explained in Definition of a Food Desert). A census tract is a small, relatively permanent subdivision of a county that generally contains between 1,000 to 8,000 people, with an optimum size of 4,000 people.

ERS's Food Desert Locator was built using Environmental Systems Research Inc. (ESRI) ArcGIS Server technology. The background topographic and satellite maps as well as the address locator service were also provided by ESRI.

Additional information on the Food Desert Locator and how it will be used for the HFFI is available on the Agricultural Marketing Service website.

Objectives

The objectives of the Food Desert Locator are:

• to present a spatial overview of where food-desert census tracts are located;
• to provide selected population characteristics of food-desert census tracts; and
• to offer data on food-desert census tracts that can be downloaded for community planning or research purposes.

How is a food desert defined?

The HFFI working group defines a food desert as a low-income census tract where a substantial number or share of residents has low access to a supermarket or large grocery store:

• To qualify as a “low-income community,” a census tract must have either: 1) a poverty rate of 20 percent or higher, OR 2) a median family income at or below 80 percent of the area's median family income;
• To qualify as a “low-access community,” at least 500 people and/or at least 33 percent of the census tract's population must reside more than one mile from a supermarket or large grocery store (for rural census tracts, the distance is more than 10 miles).

What can users do with the Locator?

• Create maps showing food-desert census tracts;
• View statistics on selected population characteristics in food-desert census tracts; and
• Download census-tract level data from food-desert tracts.

How is the Food Desert Locator related to the Food Environment Atlas?

The Food Desert Locator maps and provides selected population characteristics of census tracts defined as food deserts—low-income neighborhoods without easy access to a supermarket or large grocery store. These characteristics are provided only for census tracts that meet the definition of a food desert.

The Food Environment Atlas provides a wider set of statistics on food choices, health and well-being, and community characteristics for all communities in the U.S. While the Food Desert Locator provides information at the census tract level, the smallest geographic level of data in the Food Environment Atlas is the county. The Food Environment Atlas also has an Advanced Query tool that allows users to identify and map counties sharing the same degree of multiple indicators.

Press Kit