The indispensable Timothy Taylor writes,

Take the two most common measures of residential segregation, the “dissimilarity index” and the “isolation index” (both explained further in a moment). Apply them to the 10 largest American cities using Census data The pattern that emerges is a large increase in residential segregation from about 1910 to 1950, segregation remaining at that high level from about 1950 to 1970, and then a sharp decline in residential segregation from 1970 up through 2010.

Read the whole thing. He is citing work by Edward Glaeser and Jacob Vigdor.

My take on this, which I will put below the fold, relates to Charles Murray’s recent book. My children experienced much more racial integration than I did while growing up. Yet I believe that they were much more segregated in other respects. And the kids in the tonier suburbs of DC are way more segregated than my kids were. Here is the building in which I lived in 1963, in an area outside St. Louis, tucked into the northwest corner of University City. It is a stone structure (originally built as a barn), carved up into three small apartments. Just to the north is a brown duplex. These cheap duplexes were built around 1960, which was when the street was paved and given its name. Even though there were no high-rise apartment buildings in the neighborhood, I think that close to a majority of us were renters.

The neighborhood was 100 percent white when we lived there. We moved away in the spring of 1964, and less than a year later fair housing legislation passed Congress, after which black families swarmed in.

But in all other respects, this neighborhood was integrated. Most people living there were in the bottom 30 percent, but scattered around, living in the same sort of modest, close-together detached homes as everyone else, there were a couple of well-off owners of small businesses, and there were some well-educated professionals, including my father, who taught at Washington U.

I am sure that on my street no one’s parents other than mine had gone to college–probably most did not graduate high school. I can guarantee you that none of the kids I played with on my street went to college (although I am sure that there were kids on other streets in the neighborhood who did).

I grew up thinking that fist-fighting was a normal activity for kids. My best friend, Damon, had a tooth chipped by a kid named Mike in a fight on Carlo Reina’s driveway (just a little west if you zoom out, across Faris Avenue), and when I cried one of my other friends asked why I was crying–since it wasn’t my tooth. The fight had been planned (just for something to do, not because any grudge was involved). Carlo’s dad was sitting under the carport the whole time, and I am sure it never occurred to him to stop it.

On the other hand, fighting involving adults was considered over the line. When Steve Stella’s mom wrestled another woman to the ground, grabbed her hair and slammed the woman’s head against the curb, the word went out that Steve Stella’s mom was nuts. She lived in the next duplex over from Damon’s. The neighboring streets were not quite that trashy. Even though the detached homes on other streets were very modest, the duplexes were a step below that.

I only got hurt once. During a mudball fight, a kid stuck a rock inside a mudball, and when it hit me it broke my glasses. Otherwise, I talked my way out of some fights, but when all else failed I had the ability to run really, really fast.

The fight where Damon lost his tooth was one of the few examples of an activity that was organized in advance and had adult supervision. Usually, we played on our own. Frequently, we would use a bat and a rolled-up newspaper, because with a ball you broke too many windows.

So the way I remember 1963, Charles Murray is right. Children of college professors or entrepreneurs or lawyers played with children of single moms (e.g., my friend Damon) and children of blue-collar workers, in a neighborhood dominated by the latter. I do not recall any children or parents indicating any awareness of class differences.

Fast forward to today. Yes, where my kids went to school the races were much more mixed. Less than 25 percent non-Hispanic white, about 30 percent black, about 30 percent Hispanic. But kids did not play on the street with one another. Instead, they were always supervised, either in school or in organized activities. I don’t think my kids ever had any friends in what Murray would call the bottom 30 percent of the income-education hierarchy. And, goodness, if you were to go to Potomac or Fairfax, you would see kids who never had any friends outside of the top 10 percent. And, of course, after high school graduation, the segregation becomes even more pronounced.

So, yes, racial segregation has declined since a peak around 1963. But segregation by income-education class has gone way up.