Was Postwar Suburbanization 'White Flight'? Evidence from the Black Migration

Leah Platt Boustan, Harvard University

In the postwar period, metropolitan areas experienced higher-than-average episodes of white suburbanization when black in-migration was high. While this may be evidence of ‘white flight’, consider that black migrants may have been attracted to cities by factors underlying the demand for suburban living (e.g., income growth), or by cheaper central city housing left in suburbanization’s wake. To disentangle this causality, I develop an instrumental variables procedure using two aspects of the black migration: (1) due to transportation routes and community networks, every city’s black migrant stock has a unique state-of-birth profile, and (2) black migration was prompted – in part – by southern agricultural change. One can then predict the growth rate of a city’s black population by weighting the predicted stream of ‘pushed’ migration from southern states by a city-specific profile. Even after accounting for migrant location choice, I find that 30 percent of postwar white suburbanization can be attributed to urban racial change.