USDA -Food Access

Project Title:  View help for Project Title USDA -Food Access

Summary:  View help for Summary             Limited access to supermarkets, supercenters, grocery stores, or other sources of healthy and affordable food may make it harder for some Americans to eat a healthy diet. Expanding the availability of nutritious and affordable food by developing and equipping grocery stores, small retailers, corner markets and farmers’ markets in communities with limited access is an important part of the Healthy Food Financing Initiative. There are many ways to define which areas are considered "food deserts" and many ways to measure food store access for individuals and for neighborhoods. Most measures and definitions take into account at least some of the following indicators of access:

• Accessibility to sources of healthy food, as measured by distance to a store or by the number of stores in an area.
• Individual-level resources that may affect accessibility, such as family income or vehicle availability.
• Neighborhood-level indicators of resources, such as the average income of the neighborhood and the availability of public transportation. 

In the Food Access Research Atlas, several options are available to describe food access along these dimensions. The Food Access Research Atlas presents a spatial overview of food access indicators for low-income and other census tracts using different measures of supermarket accessibility. It provides food access data for populations within census tracts and offers census-tract-level data on food access that can be downloaded for community planning or research purposes. This Atlas can be used to create maps showing food access indicators by census tract using different measures and indicators of supermarket accessibility. It can be used to compare food access measures based on 2015 data with the previous 2010 measures, view indicators of food access for selected subpopulations, and download census-tract-level data on food access measures.

Original Distribution URL:  View help for Original Distribution URL https://www.ers.usda.gov/data-products/food-access-research-atlas/download-the-data/

Subject Terms:  View help for Subject Terms food security; food shortages; food supply; food; low income groups

Geographic Coverage:  View help for Geographic Coverage United States

Time Period(s):  View help for Time Period(s) 2010 – 2015

Data Type(s):  View help for Data Type(s) census/enumeration data; geographic information system (GIS) data

Collection Notes:  View help for Collection Notes Methods used to estimate low-income and low-access census tracts in 2015 are largely the same as methods used in previous estimates. There are, however, a few notable differences.Spatial analysis, string matching, and manual review methods were used to merge the SNAP and TDLinx data sets to construct a combined store directory. This combined directory encompasses all the supercenters, supermarkets, and large grocery stores from each data set; duplicate entries were eliminated as much as possible to avoid double counting. This matching process identified SNAP and TDLinx stores that were within a 1/3-mile radius of one another, or within the same ZIP Code. An automated string matching algorithm was used to identify exact or similar store name/address matches, which were then manually verified. Supermarkets from either the SNAP or TDLinx systems without a match in the other system were included in the final combined directory.For vehicle access and SNAP participation, tract-level 2010-2014 estimates of the share of housing units without vehicles and the share of housing units participating in SNAP are multiplied by the 2010 count of housing units to obtain an estimate of the number of households without vehicles and the number of households participating in SNAP. For income, tract-level 2010-2014 estimates of the share of individuals below 200 percent of poverty are multiplied by the 2010 count of the population to obtain an estimate of the number of people with income at or below 200 percent of poverty. These numbers and shares are then similarly aerially allocated down to the ½-kilometer-square grid level. In previous updates, direct estimates of income and vehicle access were used, instead of relying on the 2010 population counts to estimate.


Because census tract boundaries have not changed since 2010, the Food Access Research Atlas can directly compare the number of census tracts that are low-income, low-access, both low-income/low-access, and other indicators in 2015 with similar estimates from 2010. Comparisons of census tract boundaries were not available earlier because the previous analysis used 2010 census-tract geography, while the original Food Desert Locator used 2000 census-tract geography.To see how the number of food deserts has changed, ERS used 2010 census data and 2010 and 2015 store data to estimate and compare the number of low-access, low-income, food-desert tracts based on 2010 census-tract boundaries and the definition of food deserts used in the previous atlas and report. By using the same geography and the same definitions, this analysis estimates the differences in the effect of income and store access on the number and percentage of food-desert census tracts between 2010 and 2015.

Data Source:  View help for Data Source Population data, including age, race, Hispanic ethnicity, and residence in group quarters, are from the 2010 Census of the Population and downloaded at the census-block level before being allocated to ½-kilometer-square grid cells. Urban or rural designation was also provided by the 2010 Census at the block level. Data on income, vehicle availability, and SNAP participation are from the 2010-14 American Community Survey and were downloaded at the block-group level (income and vehicle availability) and tract level (SNAP participation) for assignment to ½-kilometer-square grid cells.Two 2015 lists of supermarkets, supercenters, and large grocery stores were combined to produce a comprehensive list of stores that represent sources of affordable and nutritious food. One store list contains stores authorized to receive SNAP benefits. The second list is from Trade Dimensions TDLinx (a Nielsen company), a proprietary source of individual supermarket store listings. Details on these data sources can be found in the report, Low-Income and Low-Supermarket-Access Census Tracts, 2010-2015.

Unit(s) of Observation:  View help for Unit(s) of Observation U.S. Neighborhoods

Geographic Unit:  View help for Geographic Unit Census Tract