Everyone knows that the suburbs made us fat. How do we know this? Because some junk scientists at some pro-planning advocacy groups put out a press release that claimed they had proven that suburbanites were fatter than city dwellers.
In fact, their research proved no such thing. But they did not hesitate to argue that their “proof” showed that America needs “to to invest in making America’s neighborhoods appealing and safe places to walk and bicycle,” which — to planners’ way of thinking — means rebuilding suburbs at higher densities.
Each year for nearly two decades, state public health agencies have conducted telephone surveys of some 200,000 people asking such nosy question as how tall they are and how much they weigh. Ominously titled the Behavioral Risk Factor Surveillance System, this survey is sponsored by the Centers for Disease Control (CDC). Based on this survey, the CDC says that American obesity rates have nearly doubled since 1990.
I have a lot of questions about the validity of this survey data, some of which I described in a Vanishing Automobile update. But for the sake of argument, let’s say the survey data are accurate.
In 2003, Smart Growth America and the Surface Transportation Policy Project announced that they had proven that “sprawling development has a hand in America’s obesity crisis.” They used the CDC data to compare obesity rates in suburbs vs. cities and concluded that the suburbs were fatter.
Curiously, the CDC data do not identify whether someone lives in a suburb or a city. But that is not enough to stop junk scientists. The CDC data do identify counties, so the smart-growth groups simply compared county rates of obesity with a “sprawl index” that the calculated for each county.
A second problem with the study is that America has been suburbanizing for more than a century, and the most rapid suburbanization took place in the 1950s and 1960s. How could this suburbanization cause an obesity crisis in the 1990s?
But an even more important problem is that the numbers associating sprawl and obesity are very weak. As Wendell Cox points out, the data show that residents of dense Boston weigh just 1.7 pounds more than Boston suburbanites, while those of denser Chicago weigh just 1.4 pounds more than that city’s least dense suburbs. These tiny difference are much less than differences found between people of varying incomes and educations, and certainly do not prove that suburbs have made Americans fat.
In order to give their study more credibility, the smart-growth advocates published a version of it in a peer-reviewed medical journal. To get into the journal, however, they had to seriously weaken their claims. Sprawl “had small but significant associations” with obesity, says the journal article. In the popular mind, “significant” means “having a major effect,” but in statistics all it means is “not random.” So the article admits the correlation between sprawl and obesity is not random, and — unlike the press release — the article nowhere claims that one caused the other.
Instead of sprawl causing obesity, two recent studies from Oregon and Canada agreed that the reverse is true: obesity causes sprawl. That is, obese people choose to live in sprawling communities because such neighborhoods are better suited for their needs. If this is true, then there is no justification for Smart Growth America’s call to rebuild the suburbs.
Another flawed study compared sprawl and chronic diseases. Like the obesity study, this one was based on a telephone survey. Like the obesity study, the survey did not distinguish between suburbs and cities, so the junk scientists who did the study compared low-density with high-density urban areas. Like the obesity study, the correlations were weak: sprawling Atlanta and Minneapolis-St. Paul both had lower incidences of health problems than compact San Francisco and New York. Yet the people who did the study were quick to blame the suburbs for various health problems.
Instead of relying on a crude telephone survey, we could take an objective look at actual health records for people living in cities, suburbs, and rural areas. One study that did so found that actual mortality rates are significantly higher in urban areas than in rural areas. Suburban rates were only slightly higher than rural rates. So much for suburbs being unhealthy.
Both the obesity and chronic disease studies have all the hallmarks of junk science. They used data bases that did not really measure what they were trying to measure (suburbs vs. cities). They found very weak correlations. They claimed that these correlations proved causation. And the groups that did these studies continue to promote the idea that sprawl is unhealthy even though more recent studies have proven them wrong.
Unfortunately, like the General Motors conspiracy myth, it appears that the junk scientists who promoted the sprawl-kills myth were successful enough that it will take a long time for this myth to die.
Unfortunately, like the General Motors conspiracy myth, it appears that the junk scientists who promoted the sprawl-kills myth were successful enough that it will take a long time for this myth to die.
It is simply amazing what the planning class will believe.
Thanks
JK
Thank you for looking at actual science this time instead of strawmen Randal. Now if you only had access to the literature and knew how to read it, instead of just believing Sam and Wendell’s spoon-fed articles, eh? There’s so much fundamentally wrong here, it’s hard to know where to start.
Speaking of JunkScience â„¢ Randal, you forgot to mention many of the other studies in the literature. I think cherry-picking is JunkScience â„¢, IIRC.
Anyway, the point is that the built environment can be a disamenity to that…er…sizable fraction of overweight Americans who suddenly are told by their doctor to stop consuming HFCS and to move around to get rid of their Type II diabetes.
Randal, your schtick is that you have ‘critiqued hundreds’ of plans. So what – you haven’t shown on this blog where just critiquing something means something.
It’s like the know-it-all who stands behind the plumber and tells him what to do. The plumber knows dang well that the know-it-all doesn’t know what he’s talking about, but walking away and having the know-it-all do it himself won’t work. Why? Because the k-i-a will just call the next guy in the phone book and bad mouth the guy who walked away. It’s chronic, see.
Anyway, for instance, this is very mislead…er…disappointing:
Another flawed study compared sprawl and chronic diseases. Like the obesity study, this one was based on a telephone survey. Like the obesity study, the survey did not distinguish between suburbs and cities, so the junk scientists who did the study compared low-density with high-density urban areas. Like the obesity study, the correlations were weak: sprawling Atlanta and Minneapolis-St. Paul both had lower incidences of health problems than compact San Francisco and New York. Yet the people who did the study were quick to blame the suburbs for various health problems.
So what.
You don’t like it. You call it flawed. Why? Well, you’re confused. The sampling and return rate on the phone survey is just fine, but you apparently either don’t know that, or wish to have the five people who don’t know any better believe you – you should have harrumphed about the study was flawed because it didn’t publish the questions. At least that would show that you understand one thing about study design (oh, that again).
You don’t have to physically distinguish between city and suburb in that paper because they used a sprawl index to distinguish and compare. Lastly, you can’t cherry-pick out two cities to show how the study is flawed, because this is public health across populations, and the summary table (with good significance and CIs, BTW) shows you don’t know what you are talking about.
Your poor readers certainly don’t get to better understand results with you relaying them, do they, especially when you don’t want to tell them what the results and discussion say about significance of findings.
DS
Even if “the built environment is a disamenity”, and I by no means grant that, it hardly means that we must build densely. Somebody who decides that they need to live in a dense environment can move there rather than demand that density move to them.
Strawman Week: Day 3
Surely an economist like you knows that peer-reviewed journals do not employ words as understood “in the popular mind.” In order to truly be credible, it must use the ACTUAL meaning of a word. In the context of statistics, significant means: “occurring not merely by chance: relating to the occurrence of events or outcomes that are too closely linked statistically to be mere chance.” That’s all they’re trying to prove, and they do so.
As for all these pro-planning organizations, that’s a farce. Most of the leading health organizations (including the Robert Wood Johnson Foundation, the Center for Science in the Public Interest, and the American Heart Association http://www.americanheart.org/presenter.jhtml?identifier=3015141) are sounding the alarm on the connection between health and the built environment, not because they were chartered to push planning on everybody, but because planning is a way to promote healthy urban design. As for aynrandgirl’s comment, these reports and remedies are not saying that density of the solution, they are saying that there are critical amenities like SIDEWALKS and crosswalks and parks within walking distance that help increase access to physical activity. This does NOT require increases in density.
A couple of years ago, I attended a public health seminar where one of the speakers was relating his difficulty at getting the word out [1] to the planning community about the built environment-health connection [2]. He was imploring the audience (health professionals and the planner who plans for environmental health) to work harder to partner with the planning community, as it’s a no-brainer.
Kids have no choice [3], see, but some don’t mention that, as it would ruin certain ideological arguments.
So, last year I began speaking to the public health community on these issues.
It’s the public health community driving this boat, and CA has responded with legislation [4] aimed at enabling [5] our built environment with tools like FBC [7] so those vulnerable populations are less affected. We can’t make their parents stop feeding them cr*p, but we can help them work it off.
The train has already left the station, and Randal is jumping up and down, complaining about…about…well who knows, really, with all the hand-waving. But it’s a very tiny noise over the train whistle.
DS
Can’t get [a] tags and titles to work today, for some reason:
[1] http://www.ajph.org/cgi/content/full/93/9/1382
[2] http://www.ajph.org/content/vol93/issue9/
[3] they’re not free to sort where they want: http://www.planningreport.com/article/1223
[4] http://fisherandhall.com/documents/ab1268.pdf , despite what Randal’s crusade says
[5] http://fisherandhall.com/documents/whitepaper-smartgrowth.pdf
[6] http://fisherandhall.com/news-articles/schwartzeneggerjuly.pdf
[7] oh, look: adaptive management http://en.wikipedia.org/wiki/Form-based_codes
“obesity causes sprawl. That is, obese people choose to live in sprawling communities because such neighborhoods are better suited for their needs.”
Coming soon; ‘Sprawl enables obesity!’
I think the planning class is missing an important point:
People’s freedom.
It is not up the elite class to tell others how to live, even if it lengthens their life.
If you want people to live long and be safe, put them all in prison.
No thanks.
JK
Jim,
It’s not about telling people how to live, it’s about requiring sidewalks so that when they decide to get off their fat asses, they actually have someplace safe to walk. If we wanted to take away their freedom to get obese in the first place, we wouldn’t be talking about expensive urban design solutions. Glad to hear that you’re willing to foot their outrageous medical bills though once they end up in the hospital at 35 with heart disease and diabetes.
N
It’s not about telling people how to live, it’s about requiring sidewalks so that when they decide to get off their fat asses, they actually have someplace safe to walk.
Butbutbut making a safe ped environment might impede the free flow of auto traffic.
Ah well, as if arguing that the auto as the only choice for transport is the key to nirvana and freedom!! so kids and old people can remain unsafe isn’t telling old people people how to live.
And the kids, stuck in these disabling environments, forced to get fat because they aren’t free to choose? Freedom!
I guess some folk won’t be moving to CA, what with all those laws about how to build attractive, safe environments.
DS
DS: I guess some folk won’t be moving to CA, what with all those laws about how to build attractive, safe environments.
JK: You left out two words:
..all those laws about proven ways how to build attractive, safe environments.
Thanks
JK
–Sam Staley
That is also why I can favor deregulation in my community, knowing full well that the result is higher density, more mixed use, etc., even though my personal/family choice has been for “typical†sprawl.
JK: Well, Dan, I hope you are working to support M37 and an end to Metro’s density mandates and an end to the UGBs.
Thanks
JK
‘
DS
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