About 62 percent of white students who take the ACT do so for the first time during their junior year of high school. Among black students, that figure is only 36 percent.

In the big picture of educational inequities in the United States, that may seem like a small issue. But as part of an ambitious effort to better understand black applicants to college, ACT is examining figures like this and finding that they have a "cascading" impact, according to Michael Hovland, a senior consultant at the testing company.

For example, Hovland said that colleges that purchase the names of ACT test takers so for recruiting purposes focus more and more on high school juniors, whom the colleges have more time to sell on their institutions. While that strategy is logical in many respects, it means that the very colleges that worry about making their classes more diverse are ignoring thousands of black students who are eventually taking a standardized test for college admissions.

Among black students who took the ACT for enrollment as college freshmen in 2004, 38 percent of the names were never purchased by any college, Hovland said. That's nearly 43,000 black high school students.

The ACT recently started collecting much more information about its test takers than it did previously, and one of the things it wants to do with that information is to give colleges a better sense of black applicants, since "almost every college wants more black applicants," Hovland said.

The data have not yet been published or formally released, but Hovland and James Sconing, director of statistical research at ACT, presented some of their findings on Friday at the annual meeting of the National Association for College Admission Counseling, in Tampa. In an interview, Hovland discussed some of the key findings, which are based on responses from about 120,000 black students who took the ACT to prepare for college admission in 2004, and were compared to responses from other groups.

The ACT study is also tracking where these black students enrolled and how they are doing in college. Hovland said that one significant finding suggested another way of looking at the issue of critical mass. Many experts have talked about this issue to suggest that black students are less likely to enroll at colleges without large black populations. But the ACT is finding that a key factor may be that black students avoid campuses that are overwhelmingly white, but may be attracted to campuses that are more diverse.

For example, only 3,587 of the black students studied enrolled at the 544 colleges where white enrollment makes up at least 91 percent of the student body. The average per college at those institutions is fewer than 7 students in the freshman class. Colleges with smaller proportions of white students did much better. There are 542 colleges where white enrollment is between 81 and 90 percent of the student body and they enrolled 16,415 black freshmen in 2004, or an average of 30. The average rises to nearly 50 black students for institutions where white enrollment is between 71 and 80 percent.

Some of the findings suggest that certain institutions -- especially rural institutions -- may have a difficult time getting a critical mass of black students. Black students say that they want urban institutions, and that's where they enroll.

Hovland said that the ACT found that 55 percent of black students who take the ACT live in large metropolitan areas (compared to 39 percent of white test takers). Of black students who live in such areas, 55 percent end up at a college in a large metropolitan area, compared to 39 percent of white test takers who live in such localities.

The ACT has also been studying retention rates of its test takers and is finding that black retention lags behind the rates for students of other racial groups.

First to Second Year College Retention Patterns By Ethnicity

The gap in retention rates is consistent with other studies, but Hovland said that there are some less expected results as well. For example, when the data are controlled for average ACT score and selectivity of institution, black students are 10 percent more likely than white students to be retained.

In addition, Hovland said that while white students outperform black students on the ACT (at highly selective colleges, the white average is 27.5 and the black average is 22.8), black retention rates go up as black students attend more selective colleges. This suggests that many colleges are reaching out with success to help black students, Hovland said.

Critics of affirmative action have suggested that the practice results in black students being admitted to institutions where they can't succeed. But Hovland said that "students, even of lower ability, who go to better schools aren't doing worse on retention as a result."