30 March 2010

Food Desert or Mirage?

I am deeply concerned, on a both personal and professional level, about food security. At the same time, I strongly believe that in order to educate citizens about an important issue, we must be as accurate as possible when disseminating information. And so, upon first glance two weeks ago, I and a number of like-minded folks in the region sent along links and tweets to our contacts about "When Healthy Food is Out of Reach," a joint report from D.C. Hunger Solutions and Social Compact. Sadly, it comes as no surprise that food deserts—here defined as an "area in the United States with limited access to affordable and nutritious food, particularly such an area composed of predominantly lower income neighborhoods and communities"—or "grocery gaps," exist in DC. Similarly, it comes as no surprise that, based on that definition, Wards 5, 6, 7, and 8 are the hardest hit.

The trouble I have with the report comes from the maps used to convey the District's food deserts, particularly Maps 3 and 4 on pages 15 and 18 of the report. Below is our annotated version of Map 4, "Food Deserts in the District of Columbia."

Click image to view larger map

What seems to have happened in the report is what Mark Monmonier calls a "Blunder that Misleads" in his book How to Lie With Maps. According to the report, the methodology for creating Map 4 is as follows:
Map 4 was developed using poverty data provided by the District of Columbia Office of Planning. The Office of Planning matched census tracts where 51 percent or more of the population lives at incomes below 200 percent of the federal poverty level with those tracts that have below-average access to full-service grocery stores (as identified by Social Compact in Map 3).
The blunder—not a lie but rather a "cartographic fallibility"—is that census block group data is used. Entire block groups are designated as food deserts that a.) have no living residents (cemeteries and parks, etc.), and so do not have much income and require no access to food, or b.) are institutionally used (hospitals, etc.), and so do not have much income but likely provide food on-site. Simply put, nearly 1/4 of the areas designated as food deserts may technically, but not realistically, fit the working definition.

Particularly during this time of increasing unemployment, homelessness, and hunger, advocacy groups across the District and the country are working overtime. Like many others, I want to help in the fight for social justice, but we need to be sure our data are airtight in order to effectively convey our messages.

Cross-posted at Greater Greater Washington.


  1. Also across from the Soldier's Home is CUA, which I imagine provides some food. They also may have included Ft Totten Park and the Glenwood cemetery in that area.

    The advocacy groups who cried wolf? May undermine their credibility on real deserts...

  2. The study didn't cry wolf. Despite the MAP taking into consideration the "dead zones" (pun intended) the DATA is certainly true. Wards 5-8 (W6 maybe not so much any more) are disproportionately underserved with limited grocery options and eateries with healthy food options. As a resident of Ward 7 I would caution that in your haste to discredit one portion of "When Healthy Food is Out of Reach" that you don't throw the baby out with the bath water. Here's my take on the report, "Food desert or Economic Oasis: http://bit.ly/deeNVo"

  3. Doesn't much of Ward 5 go to the Giant on the Maryland side of Eastern Avenue to shop? I know the concept of "food deserts" is a bit diluted in DC when you have many cases of supermarkets on the wrong side of the District line.

    Similar cases of "food bleed" take place with much of Ward 3 going to the Chevy Chase Giant and Ward 4 and the Downtown Silver Spring Giant (both 1.5 blocks from the District line). It's a real thing that dilutes figures and makes them more meaningless.

  4. You make an excellent point. Remember that this argument is being made by "advocates" for more funding, so it serves the purpose to create what they call "food deserts."
    I shop in many of these so-called "food deserts" and the reality is otherwise. Even the much-maligned corner store reacts to the demands of its customers. If they want chips and Vienna sausages, voila! the shelves are stocked with those. If they ask for better things, the owners respond, and there are many that stock a good variety of healthy foods at reasonable prices.

    Another question is how the "advocates" define "healthy foods." They might not be satisfied with plain onions, carrots, cabbage, potatoes, frozen and canned vegetable, but some groups can feed their families a healthy diet from very simple, inexpensive items.
    Murray's does not = Whole Foods, but does everyone want WF? Would they patronize such stores even if they were across the street?

  5. @Anonymous10:45 Yes, of course, advocates consider the vegetables you listed as healthy food(?!). If you read the report and watched the video, you would note the report's partners discuss the Healthy Corner Stores initiative where they have tried to help corner stores to improve their product offerings past the vienna sausages. Helping the mom and pop/convenience stores improve their product offerings would also help with the retail leakage previous posters describe.

  6. Deanwoodenizen: Just to be clear (and also b/c I'm not sure if you're referring to the original post or dano's comment), the intent of my constructive criticism isn't to discard the entire report, but to make sure that when we fight these good fights, we have solid data backing us up. Here, the map is the data - and with GIS software, that is often the case because of the underlying database that is essentially turned into a 2D image.

    It is also worth noting, as pointed out over on the cross-posting at GGW, that Yes! stores weren't included in the study as "full-service grocery stores," nor were the PanAm Supermarkets on Queens Chapel NE and 14th Street NW (and likely others I've overlooked). These are all important points for the credibility of the report.

  7. Also note that the ares bounded by NY Ave, Pennsylvania and 7th is immediately adjacent to the new Safeway at New York and 5th. A very mixed demographic shops there. Surely this was missed in the analysis and would evaporate that portion of desert (so to speak).

  8. As a cartographer I thought you might enjoy this site:


  9. Anonymous: Thanks for pointing that site out, it's wonderful (I do already have it in my RSS reader, but I hope other readers will consider adding it to their readers as well)!


You can be curmudgeonly too, but let's try to be civil and constructive here, ok?