How Should We Define the Suburbs?

Urbanists like to extoll the virtues of cities and urban living. But America remains a suburban nation, with the lion’s share of its residents residing in suburbs. Research shows that suburbanites are happier, reporting higher levels of subjective well-being than their urban counterparts. And as my CityLab colleague Amanda Kolson Hurley argues in her new book, U.S. suburbs defy Truman Show or Desperate Housewives stereotypes, and in fact come from a more diverse set of experiments than we give them credit for.

Given how many Americans live in suburbs and the importance of these communities to the mythology of the American Dream, it is amazing that we lack serious data-driven assessment of their types, dimensions, and characteristics. Most urban research focuses on cities and metropolitan areas; suburbia is a leftover category, or just a foil for cities.  

The problem stems from the fact that U.S. statistical agencies (the Census Bureau and Office of Management and Budget) do not provide a systematic definition for suburbs. They offer classifications for metropolitan areas and micropolitan areas, a classification of urban and rural areas, and a category of principal cities, but nothing of the sort for suburbs.

Now a working paper by Whitney Airgood-Obrycki and Shannon Rieger of Harvard’s Joint Center for Housing Studies does yeoman’s work in filling this gap. The researchers organize a wide variety of statistical data to provide a detailed portrait of America’s suburbs.  

Airgood-Obrycki and Rieger identify and compare three academic approaches to defining suburbs “that are representative of attempts to understand suburban space.” First, the “census-convenient” definition basically classifies suburbs as all the places in a metropolitan area that aren’t a principal city and don’t have more than 100,0000 people.

A second definition, drawing on literature on suburban ways of life or “suburbanisms,” defines suburbs based on commuting patterns, homeownership rates, and the proportion of single-family homes, which generates a continuum of four types of urban and four types of suburban areas.

Finally, a third, “typology” sorts urban and suburban tracts based on their population density and the age of the housing stock, and differentiates between inner (denser and older) and outer (sparser and newer) suburbs.

Even though these methods differ, they yield broadly similar pictures of suburban America. Based on where they overlap, we can draw some general conclusions.   

Most Americans live in suburbs.

This is true regardless of which definition is used. Under the “suburbanisms” definition, suburbs are home to roughly 60 percent of the U.S. population (about 164 million people); by the census definition, nearly 70 percent; and according to typology, close to 80 percent (215 million). Almost four in 10 Americans live in the most suburban communities (going by “suburbanisms”)—those with high levels of car commuting, homeownership, and single-family houses. According to the typology definition, just over half of Americans live in outer suburbs, and 25 percent live in inner suburbs.

The vast majority of suburbanites own single-family homes.

Roughly three-quarters of suburbanites (in all suburbs) own their own homes, compared to less than half of city-dwellers and 60 percent of those in inner suburbs, when broken out by typology. Single-family homes account for three-quarters of suburban housing, compared to just 40 or 50 percent of housing in urban areas. The average suburban home in America was built in the 1970s.

More than 90 percent of suburbanites commute by car.

More than nine in 10 suburbanites commute to work by car, across all three definitions. Not that urban residents are far off that: 75 to 85 percent of city-dwellers drive to work, depending on the definition used.

Suburbs are less dense than cities, but denser than you might think.

Suburban neighborhoods are less dense than urban ones by definition. But the analysis suggests that the median suburban neighborhood is fairly dense, housing approximately 1,800 to 2,000 people per square mile. That’s not far off the threshold for an urban area—2,213 households per square mile—proposed by housing economist Jed Kolko.

Still, it’s considerably less dense than the 5,000-to-8,000-person-per-square-mile range of U.S. urban areas. By the typology definition, U.S. inner suburbs have a fairly urban density of more than 4,000 people per square mile, while outer suburbs have a much lower density (just 890 people per square mile).

Despite rising suburban poverty, suburbs are quite affluent.

Median income is higher in the suburbs than in cities: roughly $60,000, compared to $45,000. The highest median incomes, of more than $70,000, are in outer suburbs. Suburban poverty has risen sharply, but the suburban poverty rate is 10 percent—about half the rate of urban areas.

The suburbs are overwhelmingly white.

Although many observers have noted the increasing diversity of suburbs and the growth of their immigrant communities, America’s suburbs are still very white. Whites comprise roughly three-quarters of the suburban population: from 72 percent to 78 percent, depending on the definition used. Despite the recent surge of immigrants moving to suburbs in large, gateway metro areas, immigrants make up just 7 to 8 percent of the suburban population, which is roughly half the rate for the U.S. as a whole. By Airgood-Obrycki and Rieger’s typology definition, core cities are much less white (about 50 percent), as are inner suburbs (55 percent).

The suburbs don’t revolve around children.

Perhaps the biggest surprise is that only one-fifth of suburban households are married couples with children. This is a sharp contrast to the 1950s image of suburbs filled with nuclear families and young kids. The average suburban neighborhood now, according to the researchers, is “composed primarily of married households without kids and single-person households.”

The share of married-with-kids households is considerably higher in the suburbs than in urban areas. However, the percentage of households with kids under 18 is remarkably similar in both kinds of places—roughly 22 percent. Nearly one-quarter (22 to 24 percent) of suburbanites live alone, compared to one-third of urbanites.

None of the definitions is perfect, and the authors note benefits and drawbacks of each. For example, the census-convenient definition captures jurisdictional divides, but it misses the typological differences between, say, Phoenix and Boston, and does not address the role of smaller principal cities within a metro area. “Deciding which categorization to use depends largely on the type of study and the conceptualization of suburbia that is most meaningful,” Rieger and Airgood-Obrycki write. They conclude that the census-convenient definition would be easiest and best to standardize, and “standardization would increase understanding of how suburban studies relate to each other.”

Hopefully, this study will encourage more urbanists to study suburbs and dig even deeper into their many characteristics and differences. The suburbs are not only where most Americans live and where a great deal of economic activity happens, but as CityLab’s David Montgomery and I have written, they are the key battleground shaping our nation’s politics and its future.