Correction: The "Asthma Capitals" Report: On Faulty Predictions and Portland
Demographia/PublicPurpose/RentalCarTour Updates
Worst score would be 9, best score would be 0 (below, paragraph 3)
http://www.fromtheheartland.org/blog/2007/01/asthma_capitals_on_fault...
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The "Asthma Capitals" Report: On Faulty Predictions and Portland
One of the all-too-many shibboleths of the anti-suburbanites is that
the rise in automobile air pollution has produced a rise in the
incidents of asthma. There is, of course, only one problem with this
view --- that for 35 years, air pollution has been dropping in the
urban areas of the United States and Western Europe. Thus, if there is
a connection between the two trends, it has to be that less air
pollution causes more asthma. Of course that is not true, but any
attempt to blame automobile produced air pollution for the increase in
asthma flies in the face of reason.
This specious claim of the anti-suburbanites has made me sensitive to
the issue. So, it was with great interest that I read the new "Asthma
Capitals" report of the Asthma and Allergy Foundation of America
(AAFA). This report provides a ranking of 100 United States
metropolitan areas using an index of 12 factors. It is a very strange
index, combining estimates of the incidence of asthma and "risk
factors," such as school inhaler access laws and poverty rates. It
might be argued that these "risk factors" (9 of the 12 factors)
contribute to the incidence of asthma, but there is no better measure
of the prevalence towards asthma than the actual cases. Only three of
the Asthma Capital criteria deal with that.
It would seem that the risk factors should predict the comparative
number of incidents. They do not and by a long shot. If, for example, a
score of 1 to 3 is given for each of the three incident categories
rates, the worst score would be 9 (the rating is simply, worse than
average, average and better than average) and the best score would be
0. The results are considerably different than the more complex index
system that includes the risk factors
Looking at the list, Atlanta, considered the worst (#1) by AAFA would
have a score of 7, not much worse than best (#100) Seattle, which has a
score of 6. Perennial urban planning favorite, Portland, ranked in the
top quarter by AAFA (#75) actually gets the worst score possible, at 9,
along with a number of other areas, along with the urban elite
favorites of New York, Boston and Washington. Colorado Springs is rated
#95 (6th best) by AAFA, yet would also have the worst possible score in
asthma incident factors, at 9, tied with Portland.
So what do the Asthma Capitals ratings tell us? Not much of anything.
The best way to compare the relative risk of asthma between
metropolitan areas is to identify the percentage of people who have
asthma. The Asthma Capitals ratings have a potential to be misleading,
given that simply are not an evaluation of the actual asthma rates in
urban areas, yet have been interpreted by some in the press to be that.
The problem is that the Asthma Capital ratings are largely based upon
predictive factors that don't predict very well at all.