The Chronicle of Higher Education has a very nice story about UCLA’s Dick Jackson. To quote this article; ”In 2001, while still at the CDC, Dr. Jackson was a co-author of an article published by Sprawl Watch Clearinghouse that contended that poorly planned built environments had adverse effects on air quality, physical activity, and public safety, among other things.”
So, my colleague is making a strong causal statement that the same person would be much healthier if he/she lived in a “new urbanist” setting rather than in the types of suburban settings that many people current live in. As an empiricist, I ask myself — how do we rigorously test this hypothesis? It is an important hypothesis to test.
There is one high quality study done by economists to examine the relationship between sprawl and obesity. These authors studied the weight dynamics for individuals who moved from center cities to suburbs. Under the Jackson hypothesis, this group should gain weight relative to observationally similar people who do not move. These authors reject that hypothesis. To really test causal claims about the role that urban form plays in determining outcomes, we need a randomized control trial. Since we choose (i.e self select) our locations , there are fundamental selection vs. treatment issues that need to be disentangled here. This is an exciting research field with opportunities for methodological advance and it is important public policy question as we think about what are the consequences of policies such as California’s SB375.