Crowdsourcing Could Help Map Urban Food Deserts

New research from the University of Texas (UT) at Dallas suggests food deserts might be more prevalent in the United States than the numbers reported in government estimates.

In a feasibility study published in the journal Frontiers in Public Health, scholars found that the methods used by the USDA to identify areas with low access to healthful foods often are outdated and narrow in scope.

Their findings suggest that crowdsourced information gathered from mobile apps such as Yelp could help provide more accurate real-time representation of food deserts in impoverished communities.

“Using data from the city of Dallas, we compared our results with the 2015 USDA database and discovered the agency needs an up-to-date source of information on grocery stores,” says Dohyeong Kim, PhD, an associate professor of public policy and political economy and of geospatial information sciences in the School of Economic, Political, and Policy Sciences at UT Dallas. “The number of food deserts may be a lot larger than what the USDA says it is.”

The USDA considers three metrics when identifying “food deserts,” areas where residents lack access to fresh and healthful food: income, car ownership, and distance to the nearest supermarket. In an effort to improve accuracy of food desert locations, the UT Dallas researchers looked at two additional variables not included by the USDA: access to public transit and shopper-provided food pricing gathered from Yelp, an online source of business reviews by the public.

“If a community has few public transportation options nearby, that may contribute to the existence of a food desert,” Kim says. “Plus, low-income households still face limited access to healthful food if prices are too high.”

The researchers analyzed data from Dallas’ 296 census tracts, which are neighborhood-sized geographical areas government agencies use to collect population data. Nine census tracts were identified as food deserts based only on the USDA’s 2015 data. Using 2018 Yelp data alone, the researchers identified 50 census tracts—mostly in south Dallas—as food deserts. Thirty-three census tracts were overlapped by both data sources.

Due to the time difference between the two data sources, Kim cautions that their findings couldn’t confirm which dataset—USDA vs Yelp—matches the situation on the ground more accurately, and he stresses that Yelp shouldn’t be considered as a replacement for government data. The results do show, however, that crowdsourced, georeferenced data could be a good supplement to improve accuracy of official government data and help guide health policies.

“Yelp data is still incomplete in coverage and limited for wide application, although it has the potential to be improved in the future,” Kim says. “This study sheds light on the need for on-the-ground, place-specific observation in the study of food deserts, and future studies should include multiple cities to gauge the quality of Yelp data across the country.”

Kim adds that use of such crowdsourced information also could give guidance to other public health mapping, such as for noise or pollution.

— Source: University of Texas at Dallas