"White flight" from American cities in the second half of the 20th century is associated with a number of problems that plague places like Detroit and Chicago to this day: the decline of urban school systems, the persistence of racial segregation, the job sprawl that pushed employment prospects even further from the urban poor.
Historic data suggests, however, that the mass exodus of the white middle class from central cities had one positive result for the people left behind: Suburban white flight helped boost black homeownership in America. And the extent of the effect is striking. Economists Leah Boustan of UCLA and Robert Margo of Boston University have estimated that for every 1,000 white households that moved out of central cities for the suburbs between 1940 and 1980, about 100 black households became homeowners.
In a fascinating paper published in the Journal of Urban Economics, the researchers argue that the two trends didn't simply occur in tandem. One directly helped cause the other. Between 1940 and 1980, a period during which Boustan and Margo examined data in 98 cities, the share of white metropolitan households in the U.S. living in the suburbs nearly doubled from 35 percent to 68 percent. Over that same time, the homeownership rate among black metropolitan households rose from 19 percent to 46 percent – a jump of 27 percentage points that had been unprecedented in American history.
Other factors certainly helped contribute to the rise of black homeownership during this time. Black incomes were rising. The mortgage market was expanding. The passage of fair housing laws in 1968 helped reduce systemic discrimination.
"However," Boustan and Margo write, "none of these factors plausibly account for the strong geographic relationship we observe at the metropolitan area level between black central city homeownership and white suburbanization."
By their calculation, 26 percent of the nationwide increase in black homeownership between 1940 and 1980 can be attributed to the white exodus to the suburbs. As white families left for newly created housing – following newly paved highways into the suburbs – demand (and prices) dropped for single-family homes in the city. As the cost of homeownership then declined, more blacks who had previously been renters – a group that now made up a much larger share of would-be home-buyers – were able to buy a home for the first time.
The effect was particularly strong in cities that had a large stock of existing single-family homes conducive to ownership, and in those central cities that had a relatively large black population. In New York City, for example, only 15 percent of the housing stock was owner-occupied in 1940. As a result, Boustan and Margo model that every 1,000 white household departures led to just 50 new black homeowners. But in Birmingham, Alabama, with its large black population and numerous detached single-family homes, 1,000 white departures generated 450 new black homeowners.
Black homeownership increased the most significantly not only in those cities with large black populations and the right kind of housing stock, but also in those metros where new Interstate construction enabled the the most dramatic population loss of white households to the suburbs.
This chart from the paper combines the predictive model above with the actual number of white households that left each city during the 1960s:
In effect, this causal relationship was ignited by the creation of the Interstate Highway System, itself an indirect byproduct of the rise of the car. By historical chance, we happened to build the highway system after the Great Migration of blacks from the South to Industrial northern cities like Detroit and Chicago. Had those chapters of history not occurred in sequence, this story might look quite different, as Boustan and Margo speculate:
Had technical advances in the internal combustion engine and the development of America’s highway system occurred a half century earlier, the prospective home buyers interested in these centrally-located homes would likely have been immigrants from Europe.
Of course, all of the other cascading effects of suburbanization might have looked different then, too. But as cities continue to confront the legacy of white flight as it actually occurred over the last 50 years, it's interesting to consider that this story may have had some small "silver lining," as Boustan and Margo tentatively frame it.