An independent analysis conducted by mapping analytics firm PetersonGIS shows that locations with the highest obesity rates contain the fewest farmers’ markets.
To produce the analysis, March 2011 data from the US Department of Agriculture (USDA) on market locations throughout the United States were mapped and correlated with county-aggregated obesity statistics* from the Center for Disease Control and Prevention (CDC).
Some market addresses weren’t completely geocoded in the USDA dataset. Those addresses that had not been geocoded were fixed to the extent possible, re-geocoded, and merged in with the main dataset.
In all, 5,858 markets were mapped. These data were subsequently intersected with the county obesity data, which had been categorized into four obesity cateogries (see table, below), and summarized to obtain a farmers’ market count per obesity category.
The analysis found that counties that fall into obesity category 1, meaning that 12% – 25% of the population aged 20 or older have a body-mass index of 30 or higher, contain 0.26% farmers’ markets by area. Counties that fall into obesity category 4, meaning that 35% – 45% of the population aged 20 or older have a body-mass index of 30 or higher, contain 0.08% farmers’ markets by area.
The data shows that there are three times as many farmers’ markets in the category 1 counties as there are in the category 4 counties.
Please note that correlation is not the same as causation.
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* This data represents estimates of obesity percentages of U.S. adults of ages 20 and older, where obesity is defined as BMI less than or equal to 30 kg / m2. The estimates are from the Center for Disease Control and Prevention (CDC). CDC used data from the Behavioral Risk Factor Surveillance System (BRFSS) for 2006, 2007, and 2008 and from the U.S. Census to estimate the number and prevalence of cases of diabetes and obesity among adults of ages 20 and older , for all 3,141 counties in the United States, as described in Estimated County-Level Prevalence of Diabetes and Obesity, United States, 2007, Morbidity and Mortality Weekly Report, November 20, 2009 / 58(45);1259-1263.
About the Author
Gretchen Peterson is the principal consultant for PetersonGIS as well as the author of GIS Cartography: A Guide to Effective Map Design.