Timberlake and Iceland examined all 323 of the nation's metropolitan areas, using Census data from 1970-2000. They searched for trends by exploring four key measures of residential inequality: dissimilarity, entropy, isolation and net difference. The researchers focused on four racial and ethnic groups: Caucasians, African Americans, Asians and Latinos. "African Americans continue to be the most segregated group from whites, but we also found that on average, African Americans have experienced greater declines in segregation," Timberlake says. "So, if that trend continues, Latinos will become the most segregated population by the middle-to-end of the next decade," he says.
Timberlake explains that the greater declines in neighborhood segregation for African Americans were likely the result of the Civil Rights movement and increasing tolerance among the white population. "Part of the reason for the sharper decline in segregation among African Americans is that their levels were so historically high, and many of the causes of those high levels have been reduced or eliminated over time," he says.
"The other factor here is that there are continuing high levels of immigration from Asia and Latin America, and all immigrants, including those from Poland, Italy or Germany for example, have historically settled in more highly segregated areas of cities," says Timberlake. "This is probably why levels of segregation for Latinos and Asians have not declined as much over time. However, the stagnating or increasing levels of Latino and Asian segregation may be temporary, if the flow of immigrants slows down in the next 10 or 20 years."
Timberlake explains that the dissimilarity and entropy measures that they used for their research examined how evenly populations were distributed. For example, the dissimilarity index compared the evenness of two groups and the entropy index traced the segregation of all of the groups examined in the study. The isolation index focused on the average percentage of ethnic groups residing in neighborhoods, and the index of net difference examined the extent to which whites resided in more economically advantaged neighborhoods than the other three groups.
All four measures indicate that residential inequality was dropping between whites and African Americans since 1970. Three of the four measures were increasing for Latinos and the measure of dissimilarity showed a marginal rise. Timberlake says that for Asians, the measure of isolation is increasing but dissimilarity and entropy are declining.
Furthermore, the study found that residential inequality declined more in cities where incomes became more equal between whites and the three other minority groups.
The study was supported by funding from the University of Cincinnati Charles Phelps Taft Research Center.