Supermarket deserts by the numbers

Gina Kolata in the New York Times this week cast doubt on claims that supermarket deserts contribute to the obesity epidemic.  The start of her article cites recent research that finds no association between supermarket deserts and risk of obesity.  It notes that residents of low-income urban neighborhoods have as much access to supermarkets as residents of higher-income neighborhoods have. 

This fact at first seems counter-intuitive to most people concerned about supermarket deserts, but it is easy to understand with some further reflection.  Low-income urban neighborhoods commonly have high population density, and they contain many medium-income residents along with the impoverished residents, so they sometimes offer too big a market for retail chains to overlook. 

The NYT article generated some controversy.  Conservative pundits, as you might imagine, falsely claimed that food deserts are a "make-believe issue" and an "Obama lie."  The liberal website Media Matters debunked the conservative coverage with typical thoroughness.  Media Matters also found "food experts" to characterize the NYT article as "misleading," which I think was too harsh a description for reporting that seemed basically sound. 

My favorite authoritative statistics about the extent of supermarket deserts put the problem into quantitative perspective, without exaggeration.  The key thing to understand is that most Americans, rich and poor, shop in supermarkets and supercenters.  Likewise, most Americans, rich or poor, shop by automobile.  Supermarkets and supercenters are fundamentally an automobile oriented retail format, and if we pretend that most people walk to the grocery store we will misdiagnose the problem.

USDA's 2009 Report to Congress about supermarket deserts emphasizes statistics showing how many households are far from a supermarket and lack access to a vehicle:

• 2.3% of U.S. households live more than 1 mile from a supermarket
  and lack vehicle access.
• 5.7% of U.S. households live more than 0.5 miles from a supermarket
  and lack vehicle access. 

One gets much higher percentages by ignoring vehicle access, but that approach is misleading.  One cannot ignore vehicle access, because, even in low-income areas, most grocery trips are by automobile.  The USDA report finds (in Table 2.9):

• In low-income areas with high access to food retail, about 65.3% of
  grocery trips are by automobile.
• In low-income areas with poor access to food retail, about 93.3% of
  grocery trips are by automobile.

Naturally, neighborhoods with adequate retail have a higher concentration of people without cars.  And in rural areas without adequate retail, even most low-income Americans shop by car.

My best summary of the evidence is that perhaps 2 to 6% of U.S. households lack good supermarket access.  Food retail access is a serious concern for people without vehicle access.  Possible remedies to improve local food retail have some merit, but should be carefully targeted based on need, and one should not expect these remedies to carry much of the burden of solving the obesity epidemic for the population as a whole.

Some low-income neighborhoods are supermarket deserts and some are not.

More from Oxfam on food aid reform

Following on another recent post, I enjoyed this video from Oxfam America, mocking what seems like the only bi-partisan consensus in Washington.  Policy-makers preserve the rules that require most food aid to be purchased domestically and shipped in U.S. vessels, regardless of the aid agencies' own assessment of the most efficient delivery options.  Lives are at stake.  Food aid should be reformed.

Imidacloprid linked to bee colony collapse

Harvard scientists recently tested the effects of the pesticide imidacloprid on bee colonies in situ, meaning out in the field instead of in a laboratory.  At each site, four hives were treated with four different amounts of the pesticide.  Beginning with the hives that received the highest doses, and continuing to the hives that received low doses, the bees died in a fashion symptomatic of colony collapse disorder (CCD).

Reactions: The scientists say their findings show that even low doses of imdacloprid, similar to those used in real agriculture, can cause CCD.  The pesticide's manufacturer, Bayer, says the low doses used in the study remained too high to be realistic.  The EPA still considers CCD to result from a mix of factors, possibly including pesticide exposure as just one factor.  That may still be a reasonable summary of the balance of current evidence, but the new study strengthens the case that pesticides -- imidacloprid in particular -- have a big role.

I follow this issue in part because my father-in-law is a retired scientist and a beekeeper.  He tracked the decline and later half-hearted recovery of his hives in lab notebooks.  In 2010, when I took a cross-country drive, visiting sites of food and agricultural interest all along the way, my starting point was his hives in Carlisle, MA.  After reading the Boston Globe article on the recent Harvard Study, he wrote a letter to the editor, which was published this week:

ONE THING we can all do is to put pressure on our elected leaders to have the Environmental Protection Agency do a better job of regulation (“Study links pesticide to bee deaths; Harvard scientists make case,’’ Metro, April 6).

The EPA does not test for the low-level chronic effects of pesticides such as those addressed in the recent studies. It also does not test for interactions between pesticides and other agricultural chemicals - and yet it is known that there are powerful synergies between some of these chemicals.

Furthermore, the EPA farms out its testing to the very companies that are producing the pesticides - kind of like the fox guarding the chicken coop.

Food aid reforms would be like money back on your grocery bill

Oxfam America and the American Jewish World Service (AJWS) explain here how much money could be saved -- and how many more hungry people could be fed -- if the United States reformed its food aid programs. Some of the key reforms include eliminating a rule that most food must be sourced from the United States and shipped in U.S. ships.

For more detail on such issues, the best book is Food Aid After Fifty Years, by Chris Barrett at Cornell and my colleague Dan Maxwell here at the Friedman School at Tufts. A good recent report comes from the GAO: Local and Regional Procurement Can Enhance the Efficiency of U.S. Food Aid, but Challenges May Constrain Its Implementation.

USDA's Know Your Farmer, Know Your Food Compass

USDA's Know Your Farmer, Know Your Food website consolidates information from a wide variety of less-well-known programs that support farmers' markets and other local food infrastructure, facilitate local meat and poultry, promote local food sales to institutions such as schools and hospitals, and more.

Rather than duplicate existing work with yet another layer of program authority, the website compiles information from a breadth of USDA agencies with their own separate budgets and chains of command.  This simple inexpensive effort makes a powerful impression, articulating a sense of shared purpose for what might otherwise seem like a scattershot collection of tiny stand-alone projects. For a Department that sometimes suffers from accusations of serving only large-scale industrial farmers, the Know Your Farmer program humanizes a large bureaucracy and generates an outsized improvement in public reputation.

For an alternative view, the coverage at Forbes seems to complain simultaneously that the Know Your Farmer program is underfunded and covers the same topics as existing programs.  With a churlish spin, Forbes shares the same facts I just described above.

Agriculture Secretary Vilsack and Deputy Secretary Merrigan this year launched the Know Your Farmer, Know Your Food Compass, with a link-heavy report and an interactive map, publicizing all sorts of local food activities supported by USDA.  Because U.S. agricultural politics are local politics, the simple act of collecting small program data points by geography has a big communication impact.

C. Peter Timmer receives Leontief Prize at Tufts

C. Peter Timmer and Michael Lipton today receive the annual Leontief Prize for Advancing the Frontiers of Economic Thought from the Global Development and Environment Institute at Tufts University.  The 1983 book Food Policy Analysis by Timmer, Walter Falcon, and Scott Pearson influenced a generation of researchers in my field. 

Timmer and Lipton will be honored today, April 3, at 3:30 pm on the Tufts Medford Campus.  Timmer will give a Friedman School Seminar tomorrow, April 4, at the Jaharis Building on the Tufts Boston Campus.

Cuts to SNAP in the Ryan budget

For many years, the Food Stamp Program enjoyed reliable bi-partisan political support.  Even as the U.S. entitlement program for cash assistance was cut and converted to a block grant in the 1990s, food stamps remained largely unharmed.  Leading Republicans such as Senator Bob Dole joined leading Democrats in supporting food assistance for low-income Americans.

Now, at a time when U.S. household food insecurity is near record levels, the nation's largest food assistance program -- under its newer name the Supplemental Nutrition Assistance Program (SNAP) -- is targeted for the most severe cuts ever in its 50-year history.  According to the Center on Budget and Policy Priorities, GOP Congressman Paul Ryan's proposed budget plan for 2013-2022, approved by the House of Representatives Thursday in a partisan vote, would cut SNAP by $133.5 billion, or 17 percent, over ten years.

In reaction to this proposed budget plan, GOP Presidential candidate Mitt Romney said, "It's an excellent piece of work."

Second-place GOP Presidential candidate Rick Santorum, according to the New York Times, said the budget didn't go far enough.

The New York Times editorial yesterday disagreed.  The Times said the proposed cuts "would mean a loss of $90 worth of food a month" for the average household.  If you read the Center on Budget's analysis carefully, clearly the Times should have said "a loss of $90 worth of food stamps in a month" (the distinction arises because SNAP benefits are effectively food support only in part and effectively income support for the remainder).  An economist colleague called me up to criticize this oversight in the Times editorial and to encourage me to post on this topic, saying of the Times: "It's an attempt to be inflammatory.  They wanted a big number."

I see the point, but I might add that the budget cut correctly described, $133.5 billion from SNAP, also is a big number, and perhaps also in this election season an attempt to be inflammatory.

Update (4/1/2012): My colleague encourages me to explain the economic flaw in the Times editorial even more clearly.  The issue has to do with the effect on food spending from an additional dollar of SNAP benefits.  A good rough estimate is that an additional dollar of SNAP benefits generates about 30 cents of additional food spending.  The rest of the additional SNAP benefit substitutes for cash income that the household otherwise would have spent on food, freeing up resources for other household needs such as housing or transportation.  The economic lesson is that a targeted benefit such as SNAP is in part a food subsidy and in part a general income subsidy.  The Times editorial should not have said the Ryan budget would generate a loss of $90 in food, but rather that the budget would generate a loss of $27 in food and $63 in other household needs.

With this correction in mind, my friend writes: "What you did not do in your blog post was tell your reader the nature of the NYT mistake and what the right concept is.... So finally, if I object, it is that you did not take this opportunity to teach a little economics and encourage accuracy.   You came very close to saying, lying is okay as long as the political cause is GOOD.   I do not think you really believe that."