Much has been written about shifting preferences toward urban living. I admit to skepticism, despite my hopes as a city resident and redevelopment consultant, of convergent preferences among the Millennial and Baby Boom generations. Alas, it appears real – extensive survey data from the National Association of Realtors, amid other quantitative and anecdotal evidence, is unambiguous. These two demographic groups, which comprise half of the U.S. population, are reshaping the landscape by leaving a less urban land use pattern for a more urban one.

The transition is noticeable. Residential building permit data for Minneapolis illustrate the fundamental reversal from market emphasis on single-family unit construction (maroon) to multi-family unit construction (blue), starting in 1996. Denser living will never be for everyone, but it seems to be increasingly attractive to many.

Human networks are the premise of urban economies. By providing a physical format for exchange of ideas, development of trusting relationships, communication about reputation and quality of products and services, cities reduce the costs associated with trade (as well as training and education or cultural events, for example). As Bob Weissbourd presents in his collaborative “Dynamic Neighborhoods,” concentrations of people and investment follow the development of stable, vibrant networks.

The majority of population, intellectual assets and economic activity located in U.S. metro areas continues to grow. We have to wonder: How can cities’ physical form be encouraged to fill in, to maximize the product of this combination of ideas and relationships? Public and private actors share a compulsion to intensify what fruits emerge from urban economies.

Ed Glaeser has asserted that decisions falter when based on “the all-too-common error of confusing a city, which is really a mass of connected humanity, with its structures.” With increasing market demand for structures that increase human connectedness, Glaeser’s bifurcation loses some of its value. As the housing crash reminded us, the development pattern of core cities isn’t a mistake – it’s an eclectic but durable form that has withstood the stresses of growth and prosperity as well as economic crash. Cities, and the neighborhoods that comprise them, are strongest when most flexible. Denser land use makes more efficient use of infrastructure for transport, housing, training and education, leaving more public resources to invest in people, who are the most essential asset in any city.

In Glaeser’s words, a city is a mass of connected humanity. True. But the degree to which that humanity is connected in a city is influenced by how the city’s structures allow people to interact. The growing momentum of higher-density building will provide basis for experimentation, and for us to better understand the relationship of structures, land use, innovation and productivity.

Analysis of 2010 Census data reveals that Americans are relocating at the lowest levels recorded since the public began tracking these trends in 1948. Mobility is influenced by conditions in housing and labor markets, which vary substantially by region or metropolitan area, and are continuously shifting.

That’s why I take issue with an interpretation recently put forth by respected author and speaker, Richard Florida, in a pair of short posts (“America the Stuck” and “The Geography of Stuck“). He distills his interpretation into a claim that “America can be divided into two distinct classes, the stuck and the mobile.” These “classes,” in his view, are not only sorting themselves geographically, but by state: Residents of coastal states are mobile, others are not.

In my view, the Census data really don’t support this narrative. As Florida and others have documented, America’s economic and cultural landscape is increasingly metropolitan. Those metro areas with the highest proportion of residents born in another state are found primarily in states that Florida highlights as “mobile”:

These data don’t support the “two class” thesis for two reasons. First, while clearly in-migration is good for regions in forms including new ideas, cultural vitality and diverse labor pools, the specific kind of mobility Florida is calling out doesn’t appear to correlate with economic strength. The right column in the table shows each region’s rank (out of 366) in income growth from 2009-10; these aren’t the nation’s star performers. Second, as the map below illustrates (click on it for a larger image or see the source brief here), mobility continues to occur within states, from rural or micropolitan regions to larger metros and among metros. This is occurring in the states he calls mobile, and in many of the states he deems “stuck.” As it turns out, neither label accurately reflects recent trends.

There are structural shifts underway, and Florida has named some aspects of these in recent years. This most recent chapter strikes me as a departure from his record of nuanced analysis. Some American communities are clearly less mobile than others, but these dynamics haven’t developed in clean ways that follow state boundaries in an either/or fashion. They’ve developed by region, subregion, and neighborhood – and that’s where our focus belongs.

Related Articles:

• Productivity and Design Merge in the Gated City
• Urban Economies: Going with the Flow
• Minneapolis Saint Paul Metro Business Plan (and Executive Summary)