A piece in the Chicago Reader discusses the results of a new University of Michigan study that showed Chicago is the third most segregated city in the country, trailing only New York City and Milwaukee. A few notes about this study:

1. Like many other studies of its ilk, this is based on dissimiliarity index scores. Here is how this is calculated:

The dissimilarity index is a system used by sociologists to measure segregation, with the highest score – meaning total segregation – being 100. The lowest – complete integration – is 0. The numbers reflect the percentage of people from one race (black and white are measured here) that would have to move in order to create complete integration.

There are some other measures like this with different calculations but the dissimilarity index seems to be used most often. There are a number of easily-found sites online that provide instructions on how to calculate the dissimilarity index (here is eHow’s explanation).

2. The Chicago Reader article and another piece at Salon (with some nice maps and explanations for each city) focus on white-black segregation. The original study also calculated the dissimilarity index for other pairs of races, such as whites and Latinos. These figures are generally lower than those for whites and blacks as the Great Migration of blacks from the south prompted increasing levels of segregation in Midwest and Northeastern cities during the early decades of the 1900s.

In terms of the white-Hispanic findings from the original study, the top 5 segregated cities are Springfield, MA, Los Angeles, New York, Providence, and Boston. On this list, Chicago is tenth.

The original study also look at white-Asian segregation: the top 5 cities here were Buffalo, Pittsburgh, New York, Syracuse, and Baton Rouge.

3. A little more on interpreting the figures regarding Chicago:

-Along with the other 52 most white-black segregated cities, Chicago had a drop (4.8) in its dissimilarity index between 2000 and 2010.  The 53rd city, Greensboro, NC, was the first on the list to have an increase (0.9).

-In the Salon piece, there is a little bit of history about how this segregation came to be in Chicago and black migration, public housing, interstates, and Mayor Daley are mentioned. The conclusion is this:

Oak Park was one of a handful of places around the country where progressive whites made common cause with blacks. But in the Chicago area, it’s the exception, not the rule. Today, middle-income blacks are increasingly moving into Chicago’s suburbs. And though Quillian says that there isn’t white flight like there was in the past, many communities appear to be resegregating. The problem now is white avoidance.

It would be interesting to hear more about this idea of “white avoidance.”

-The Chicago Reader piece also suggests that Pekin, Illinois (a town whose high school has had some issues regarding race and its mascot – link from Wikipedia) is the most segregated city (white-black) in Illinois. However, the story doesn’t add the caution regarding Pekin: there are 857 blacks in the community. The CensusScope page of Illinois cities by dissimilarity index adds this disclaimer:

When a group’s population is small, its dissimilarity index may be high even if the group’s members are evenly distributed throughout the area. Thus, when a group’s population is less than 1,000, exercise caution in interpreting its dissimilarity indices.

It would be helpful if this were added to the story regarding Pekin.