Monday, May 11, 2009

Mapping the money

Check out this cool set of maps showing the higher-income neighborhoods for each of the 25 largest U.S. metros (hat tip to NeoHouston). Most cities show a similar pattern with a small area of wealth in the core, surrounded by the poor, then some middle class suburbs, then more wealth on the edges. From the page:

These maps show the distribution of income (per capita) around the 25 largest metropolitan areas in the US (all those with population greater than 2,000,000). The goal was to test the "donut" hypothesis — the idea that a city will create concentric rings of wealth and poverty, with the rich both in the suburbs and in the "revitalized" downtown, and the poor stuck in between.

This does seem to have some validity in older cities like Boston, New York, Philadelphia, or Chicago, but in newer cities it is not the case. Instead of donuts, one finds "wedges" of wealth occupying a continuous pie-slice from the center to the periphery.

Just from visual inspection, it also seems that poverty donuts all tend to have about a five-mile radius, regardless of the size of the city. Perhaps this is the practical limit for commuting without a car?

The "wedge of wealth" definitely defines Dallas (north), Atlanta (north), and Houston (west), although you can see more all around if you go farther out. In Houston, the west wedge if obvious, but you can also see Kingwood, Clear Lake, Sugar Land, and Willowbrook/NW. The map does not go out far enough to show The Woodlands. As far as our gentrifying areas, note the gray middle-class areas in the core north and east of the red wedge, such as The Heights and the Washington corridor - so the wedge is growing both inward and outward.

One flaw in the maps is they only show federal interstate highways, not state freeways, so a lot of key freeways are missing (like 59, 290, 249, 288, etc.).

One other observation from these maps: often metros are ranked by population, but there's always been a bit of a mismatch between population size and perceived importance. Some smaller metros are subjectively considered "more important" (SF Bay Area, DC, Boston) than some larger cities (DFW, Houston, Atlanta, Detroit, Phoenix). In these maps, you can sort of see why: those cities have much larger high-income areas, which means more professionals with higher education. Check out Chicago vs. the SF Bay Area, Atlanta vs. DC, or Detroit vs. Boston. Or, if there were more maps, I'd bet you'd see the same thing with larger San Antonio vs. smaller Austin. I'm not saying it's fair or right, just how different metros are perceived that jumps out in these maps.

Please feel free to share your own observations from the maps in the comments.

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At 2:02 AM, May 12, 2009, Anonymous Neal Meyer said...


The commenter who made the statement about 5 miles being the practical limit of how far one can commute without a car is onto something. Edward Glaeser, Matthew Kahn, and John Rappaport wrote a paper more than two years ago in the Journal of Urban Economics, where he addressed the urbanization of poverty. Glaeser, Kahn, and Rappaport stated that the urbanization of poverty comes from better access to public transportation.

I cannot distribute a non-gated version of the paper, but here is a research brief that discusses the research without the formal math modeling. It also includes some data on distance between income belts and CBD's.

I've read the formal paper, which also includes building a model which incorporates an idea of how it is that an urbanized area can have wealthier people who decide to take public transportation, while having other areas where poorer people decide to drive cars. Glaeser, Kahn, and Rappaport strongly suggest that housing based explanations alone are not sufficient to explain poverty urbanization, noting that the income elasticity for land is too low.

What would be really interesting is to take these same maps and cross reference them to the bus or rail networks in each city, in addition to your idea of adding the freeway network.


At 6:53 AM, May 12, 2009, Blogger Tory Gattis said...

This helps explain why so many middle and upper class areas resist transit service. Thanks for the links.

At 8:21 AM, May 12, 2009, Anonymous Mike said...

Another thing to say about SF and DC is that a few years ago when their metro areas included all the Bay Area for SF and Baltimore for DC, they really were larger than DFW or Houston. So it kind of depends how you split it up, and you can argue that all of the Bay Area contributes to SF's significance and that Baltimore contributes to Washington's significance.

At 8:32 AM, May 14, 2009, Anonymous Mike said...

I remember Peter Marzio, director of the MFAH, once saying that when it came to fundraising, "compared to New York, LA, and Chicago, we don't have two dollars." I didn't realize how true that was until I saw this.

At 8:40 AM, May 14, 2009, Anonymous Mike said...

Just had this thought... I wonder what percentage of our red area has zoning restrictions of some kind? You can see where the red/pink abruptly ends at the edge of some of the Villages.

At 8:54 AM, May 14, 2009, Blogger Tory Gattis said...

I heard the exact opposite from the head of local Red Cross: tons of support. But I could see there being a limited population of art lovers here. Probably not a ton of demographic overlap with the moneyed people of the energy industry. But I hear a lot made of the claim that we have all of the major performing arts groups (major theater, opera, symphony, ballet), which is rare among cities in this country, so there's definitely some strong support somewhere.

Clearly the small municipalities with zoning have attracted many of the wealthy. Zoning is often a tool of exclusivity to keep out undesired populations. But they also have much lower property taxes because they aren't supporting services for lower-income populations (esp. a large police force). So you can't say zoning is necessarily the prime attractor here. Also consider the most wealthy and exclusive neighborhood in Houston: River Oaks - no zoning, just private deed restrictions.

At 12:47 PM, May 14, 2009, Anonymous Mike said...

I don't think Marzio meant that people in Houston aren't supportive of the arts. I think he meant that Houston, compared to NY, LA, and Chicago, does not have a lot of money.

I guess the reason River Oaks has no zoning is that it's part of Houston? But very strong deed restrictions and ordinances.

At 1:56 PM, May 14, 2009, Blogger Tory Gattis said...

My suspicion is that Houston's business and engineering "new money" is not as supportive of art vs. "old money" Chicago and NYC + rich entertainers in LA. I've also heard of struggling arts organizations in SF, which does not surprise me: it's not really the scene for rich techies.

> I guess the reason River Oaks has no zoning is that it's part of Houston? But very strong deed restrictions and ordinances.

Yes it is. Deed restrictions - no special ordinances (which are citywide).


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