Socio-Spatial Segregation: Wacquant, Massey and Sassen

Socio-spatial segregation is the physical separation of social groups within a city according to income, origin or ethnicity, so that economic inequality becomes geographic distance. It is measured with indices such as the index of dissimilarity, which shows what share of a group would have to move for it to be evenly distributed. Three authors have explained its causes from complementary angles: Loïc Wacquant studied advanced marginality in ghettos and peripheries, Douglas Massey documented residential apartheid in the United States and Saskia Sassen showed how the global economy polarises large metropolises.

Loïc Wacquant and advanced urban marginality

In Urban Outcasts (2008), Wacquant compares the Black ghetto of Chicago's South Side with the banlieue of La Courneuve outside Paris. He concludes that they are not the same phenomenon: the American ghetto is a racially homogeneous space abandoned by the state, while the French periphery is ethnically mixed and still sustained by public services. What they share is advanced marginality, a new form of exclusion produced by precarious work, welfare retrenchment and territorial stigmatisation, which marks residents by their address more than by who they are.

Douglas Massey and American apartheid

Massey and Nancy Denton showed in American Apartheid (1993) that racial segregation in US cities is not the result of individual preferences or of poverty but of decades of deliberate policy: redlining on mortgage maps, restrictive covenants in deeds, the siting of public housing in already segregated areas and discriminatory practices by real estate agents. The outcome is the hypersegregation of African Americans in several metropolitan areas, which concentrates poverty and cuts residents off from the jobs, schools and networks that make upward mobility possible.

Saskia Sassen and polarisation in the global city

Sassen, in The Global City (1991), analyses New York, London and Tokyo as command centres of the world economy. The concentration of finance and advanced services creates very well paid jobs, but also a large demand for low-wage work, cleaning, catering, care, met largely by migrants. That occupational polarisation turns into spatial polarisation: central districts gentrified for global professionals and peripheries or enclaves where the precarious workforce is concentrated. The global city is, for Sassen, a dual city.

Consequences of segregation and policies to reduce it

All three agree that segregation is neither natural nor inevitable but the product of decisions about housing, credit, transport and services. Its effects are inherited: growing up in a segregated neighbourhood reduces children's educational and job prospects regardless of family income, as Raj Chetty's studies of intergenerational mobility have measured. Reducing it requires social housing dispersed across the whole city, public transport linking peripheries to employment centres, investment in the schools and public space of stigmatised districts and enforcement against discrimination in the housing market.

In Latin America segregation takes the form of self-built peripheries facing gated condominiums, and in Europe that of ageing public housing estates where immigration concentrates. In every case the lesson of Wacquant, Massey and Sassen is the same: geographic proximity does not guarantee equal opportunity, and a city that tolerates invisible borders between its neighbourhoods ends up reproducing the inequality it claims to fight.