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Fri, 23 Sep 2005
This is more of a rant than a continuation of the previous post.
I am at a loss to explain how low are the standards of policy research that guide major urban decisions. This started when I first saw a planning study of the introduction of highrise apartment building in a lowrise area. The traffic impact was calculated to several decimal places for blocks away. They had hired a group of engineers who modelled it 6.283 ways to Sunday. But the social impact? To the extent that it was there, it was simply wrongheaded speculation based on nothing.
These are important issues. Why do people choose to live where they do? What is it about a building and its surroundings that determines who will live there? If there is nowhere for families to live, where will they live? What about old people? Poor people?
I put together a 2-parameter model. It predicted the future percentage of households with children by neighbourhood based on current distributions of density and of households with children. It correctly predicted cases where the increase in construction of new units in certain types of neighbourhoods will actually decrease the population. It turns out that a large proportion of types of changes to urban planning policy end up increasing the total amount of land required to house the same population. Certain types of changes decrease it.
In an era of smart growth, where we are trying to curb sprawl for a whole host of reasons, this type of analysis is essential and it's simply not being done. It is polically charged and no one wants to have their opinions tested with any real analysis.
One of the people I most admire right now is George Galster of Wayne State University. I don't usually agree with him, or rather I think the world would be a better place if he were more often wrong. But his research methodology seems to be a genuine search for the the actual causes and actual effects of sprawl, poverty, and other urban social issues.
For instance, most "research" on the effects of subsidized housing on surrounding property values consist of a simple linear regression after the fact of the price of houses sold, compared to a control area, and concludes that there is no effect on property values. This is the politically satisfying conclusion that they were clearly looking for all along. Galster's research tries hard to use whatever data and statistical analysis is required to eliminate statistical bias and noise and get at the actual effects. And they are not what any political school of thought wants them to be.
To paraphrase, a community gets one public housing project with little social or economic impact. After that, rich communities can take more and poor ones can't. Since subsidized housing tends to go on lots that are depressed in value, it actually increases their value in richer areas and keeps the entire area down in poorer ones.
Now, why can't we take rigorous research of this type and turn it into a model similar to the traffic models? Why can't urban planners go to social and environmental planning consultants, run a proposed development through a model and come out with figures like "This project will increase the population of wealthy empty nesters by 204 people and reduce the population of working families by 163 people within a 3-block radius. The net loss of households with school age children will be 46. It will result in an additional 327,000 vehicle kilometres travelled and 149 tons of greenhouse gases in CO2 equivalents per year, based on a household relocation model"