Measures of Segregation

Court decisions dating to the 1950s theoretically ended racial segregation of higher education in the United States. But data to be presented today at the annual meeting of the American Economic Association show that the pace of desegregation has slowed over time. And in a finding that could be controversial, the study finds that states that ban the consideration of race in admissions may see the pace of desegregation accelerate.

The study is by Peter L. Hinrichs, an assistant professor of public policy at Georgetown University. He focuses on black and white students, not those in other racial and ethnic groups, and he examines "exposure" and "dissimilarity" (defined below) of black and white students as two measures of desegregation. Hinrichs uses federal data from every college, filed since the era in which desegregation started. He argues that these measures illustrate the extent to which colleges are truly desegregated, which may not be reflected simply by increases or decreases in black student enrollments (which can be concentrated at certain institutions).

Exposure is the percentage of black students at colleges attended by white students, and vice versa. Here he shows that from 1968, the typical white student attended a college that was 2.3 percent black. But by 2009, the typical white student attended a college that was 9.8 percent black. This percentage gain is much larger than overall black enrollment during this period, which also rose, from 5.5 percent to 13.7 percent.

While the growth in exposure has been steady, there have been some notable changes. Throughout the '80s and '90s, for example, the public institutions attended by white students had higher black enrollments than did private institutions. But shortly after 2000, public and private exposure rates shifted. In the most recent data, white students at private colleges were, on average, at institutions that have a black enrollment of nearly 12 percent while those at publics were under 9 percent in black enrollment. In an interview, Hinrichs said he didn't know why public and private positions had flipped, but that he thought this was an important issue to study.

White exposure to black students has steadily increased, while black exposure to white students increased rapidly in the early 1970s, as colleges -- both those that had been de jure and de facto segregated -- opened their doors to black students. But the rates have fluctuated since then. In the 1980s, black students attended colleges that were, on average, between 50 and 55 percent white, with the averages for public institutions slightly greater than for private institutions. By 2009, the average was 49.2 percent white students at institutions attended by black students. This suggests, Hinrichs said, that in more recent years, more black students have enrolled at institutions with large minority populations. He said that this could raise concerns given that, many educators say, these are not the institutions that receive the most resources from either state or private sources.

The other measure he examines is "dissimilarity," which examines the extent -- on a scale of 1 to 100 -- to which black and white students attend similar institutions. So if every college in the country had 10 percent black students and 60 percent white students, the index would be 0 because the black and white enrollment patterns would be identical. If black students and white students all attended institutions without any students of the other race, the index would be 100. (The index is used by other social scientists as well, to measure the extent of desegregation in neighborhoods, public schools and so forth.)

In his analysis of the numbers for higher education, Hinrichs found that the index fell sharply in the direction of desegregation as the civil rights movement and court rulings led predominantly white colleges to recruit black students. In 1968 the index was 63.9 percent, and by 1972, the index had dropped to 52.5 percent. But since then, movement has been modest. and the figure had dropped only to 48.0 percent by 2009.

In an interview, Hinrichs said that it is hard to say what the index should be in a desegregated society. He noted that elementary and secondary schools have a higher index. Further, he said that most students (of all races) attend colleges and universities near where they live. Since the black population is not evenly distributed in the United States, there are likely to be regions where colleges have relatively low black enrollments. Likewise, there are institutions -- such as historically black colleges -- whose missions have resulted in their enrollments being largely black even in a post-segregation era. So it's not realistic, he said, to expect a rate of 0. At the same time, he said, that doesn't mean that the current figures aren't cause for concern.

Further, he said that much of the progress toward desegregation in both measures comes from black students increasingly attending institutions other than historically black colleges -- not from more black students attending all kinds of colleges (although that is also a factor).

The Impact of Affirmative Action Bans

One reason that desegregation measures matter, the Hinrichs paper notes, is that arguments made by colleges for why they should continue to consider race and ethnicity in admissions stress the educational benefits of people being educated in diverse environments. Since several states have either permanently or temporarily dropped consideration of race and ethnicity in admissions following either court rulings or referendums ordering such a shift, Hinrichs studied the impact of the bans on his desegregation measures.

He looked at states from 1995 through 2003, a period in which California, Florida, Texas and Washington State banned affirmative action in admissions. He found that in states that eliminated the consideration of race in admissions, black students saw a gain in their exposure to white students (of 1.45 percentage points) and a decrease of the dissimilarity index of 1.66 points. That means, he said, that the result of the bans was not to exclude black students from higher education but to redistribute their enrollment -- and to do so in ways that more closely reflected enrollment patterns in those states.

Hinrichs is quick to say in the paper (and in the interview) that his findings do not suggest that states should ban affirmative action. (Hinrichs said he describes himself as neither a supporter or critic of affirmative action, seeing both benefits and problems with the practice.) He said that there are valid reasons for people to want to assure higher levels of black enrollment at elite institutions than might be the case without affirmative action. But he also wrote that the data show that "it is plausible that an affirmative action ban could decrease measured racial segregation."