Statistics on Sprawl Meaningless if They Oversimplify

"Sprawl index" oversimplifies a complex process

Every political movement needs a statistic, and nowhere is this more true than in the so-called Smart Growth movement.

The statistic du jour is something called a “sprawl index,” which supposedly identifies the real culprits in sprawl – states and cities developing land at a faster rate than their population growth. The sprawl index got a big boost when the Brookings Institution recently released a study claiming that developed land grew almost three times faster than the population in America’s metropolitan areas from 1982 to 1997.

Like most politically driven statistical measures, however, the index oversimplifies a complex process. Embracing it implies that population and land development growth rates should be the same. This is an absurd standard; taken literally, it would suspend the dreams of millions of homebuyers and seriously compromise the quality of life for millions of families.

Let’s jump back 50 years to see why. This is urban America right after World War II, before modern suburbs, the interstate highway system and the creation of mass-produced affordable housing communities. Many, if not most, people live in apartments or row houses in densely populated inner cities.

How dense? A four-floor apartment building, housing families with an average of two kids, two families per floor, would generate a housing density of about 134,000 people per square mile. While some blocks achieve these densities, most cities are less dense on a citywide basis because the overall density is diluted by land uses that don’t house people – roads, office buildings, schools, parks, etc.

In contrast, a contemporary suburban subdivision, populated with similar families with houses on lots of a half-acre would generate a residential housing density of about 5,000 per square mile (often less than 2,000 once the other land uses are added in).

Let’s say our apartment families, whose parents toil away on the local assembly line, scrape together enough money to rent a new row house – an attached single-family home fronting the street with a small yard in the back. Since this is a growing city, these families are replaced by new households and the population doubles.

But, the move means land development outstrips population growth by three to one because the homes are next to each other, not stacked on top of each other in one building.

Is this rampant, uncontrolled sprawl that must be stopped? If the sprawl index is to be taken seriously, it is. The only way population growth could match land development is if these families moved into a new apartment building at the same density – no yard, no additional living space and no garage.

The index, it turns out, is a crude measure that obscures more than it illuminates. Cities, like economies, evolve, and where a city takes off economically has an impact on its architecture, design and housing patterns.

Take two cities, close geographically, but worlds apart in economic legacy and land use are Cleveland and Columbus, Ohio. Industrial Cleveland has seen its population density fall by more than a third from its post-World War II high of almost 10,000 people per square mile. While the city is experiencing a modest housing renaissance, new housing is primarily suburban. In fact, new housing in the city’s inner-city Hough neighborhood is virtually indistinguishable architecturally from similar homes in suburban settings.

Meanwhile, a couple hours south, population densities will increase by at least 9 percent in half of Columbus’ neighborhoods. With fewer than 2,000 people per square mile, however, Columbus’ citywide population density is about one-third of Cleveland’s and consistent with suburban lifestyles.

A sprawl index would give Columbus high marks because its density will increase and Cleveland low marks because its population density will fall. Yet, the key to success for both cities is providing housing that fits the modern household – larger homes with more luxury characteristics, automobile accessibility and a small yard.

In a nation where only 5 percent of the land is developed, and only one state (New Jersey) has developed land exceeding one-third of its total surface area, statistical measures such as a sprawl index are meaningless. Ultimately, they serve little purpose other than to conjure up unsubstantiated fears about land use and dismiss immediately accessible land as a desirable characteristic of housing.

More importantly, perhaps, they provide almost no guidance to local policy-makers and elected officials struggling with the real problems of growth – rising traffic congestion, deteriorating environmental quality and rising infrastructure costs. The challenge for elected officials and citizens is to come up with specific solutions for specific problems, not use meaningless statistics to adopt broadbrush approaches to land use that run counter to what people really want.

Samuel Staley is director of urban and land use policy at Reason Foundation and co-editor of the book “Smarter Growth: Market-Based Strategies for Land-Use Planning in the 21st Century.”

Samuel R. Staley, Ph.D. is a senior research fellow at Reason Foundation and managing director of the DeVoe L. Moore Center at Florida State University in Tallahassee where he teaches graduate and undergraduate courses in urban planning, regulation, and urban economics. Prior to joining Florida State, Staley was director of urban growth and land-use policy for Reason Foundation where he helped establish its urban policy program in 1997.

Staley is the author of several books, most recently co-authoring Mobility First: A New Vision for Transportation in a Globally Competitive 21st Century (Rowman & Littlefield, 2008). Texas Gov. Rick Perry aid Staley and Moore "get it right" and world bank urban planner Alain Bartaud called it "a must read for urban managers of large cities in the United States and around the world."

He is also co-author, with Ted Balaker, of The Road More Traveled: Why The Congestion Crisis Matters More Than You Think, and What We Can Do About It (Rowman and Littlefield, September, 2006). Author Joel Kotkin said, "The Road More Traveled should be required reading not only for planners and their students, but anyone who loves cities and wants them to thrive as real places, not merely as museums, in the 21st Century." Former U.S. Secretary of Transportation Mary Peters said, "Balaker and Staley clearly debunk the myth that there is nothing we can do about congestion."

Staley's previous book, Smarter Growth: Market-based Strategies for Land-use Planning in the 21st Century (Greenwood Press, 2001), was called the "most thorough challenge yet to regional land-use plans" by Planning magazine.

In addition to these books, he is the author of Drug Policy and the Decline of American Cities (Transaction Publishers, 1992) and Planning Rules and Urban Economic Performance: The Case of Hong Kong (Chinese University Press, 1994).

His more than 100 professional articles, studies, and reports have appeared in publications such as The Wall Street Journal, The New York Times, Washington Post, Los Angeles Times, Investor's Business Daily, Journal of the American Planning Association, Planning magazine, Reason magazine, National Review and many others.

Staley's approach to urban development, transportation and public policy blends more than 20 years of experience as an economic development consultant, academic researcher, urban policy analyst, and community leader.

Staley is a former chair for his local planning board in his hometown of Bellbrook, Ohio. He is also a former member of its Board of Zoning Appeals and Property Review Commission, vice chair of his local park district's open space master plan committee, and chair of its Charter Review Commission.

Staley received his B.A. in Economics and Public Policy from Colby College, M.S. in Social and Applied Economics from Wright State University, and Ph.D. in Public Administration, with concentrations in urban planning and public finance from Ohio State University.