The U.S. Supreme Court is now revisiting affirmative action at elite colleges. Even after decades of reviewing preferential admissions policies, there is still no consensus regarding how affirmative action impacts black students.

In response, affirmative action opponents offer the “mismatch theory” - the perception that attending a college that surpasses demonstrated ability is detrimental to degree completion. The mismatch hypothesis was recently discussed by the late Justice Antonin Scalia in the Fisher v. Texas oral arguments: “There are those who contend that it does not benefit African-Americans to get them into the University of Texas where they do not do well.” He noted that mismatched – or more specifically, overmatched –  black students would have better outcomes if they attended “a slower-track school where they do well.”

Nonetheless, the evidence for this type of mismatch points to positive effects for black undergraduates with low academic qualifications attending more prestigious institutions. Contrary to Scalia’s controversial contention, the data show that black students tend to have much higher graduation rates at the most selective colleges and universities than at the less selective ones.

In a national sample of 650 black students who first enrolled at the most selective four-year colleges and universities during the 2003-2004 academic year, 66 percent of these students received degrees, as compared to a graduation rate of only 23 percent for black undergraduates enrolled at minimally selective colleges – the institutions Scalia recommended.

Comparing black students with similar academic qualifications, data from the 2003 – 2009 Beginning Postsecondary Student Survey show that mismatched (overmatched) black undergraduates – those with low GPAs and standardized SAT/ACT scores matriculating at the most selective schools – were far more likely to earn a degree within 6 years than were their peers attending minimally selective institutions that matched their academic qualifications.

Mismatch actually harms academically talented black students

Another way to test the effects of mismatch is to assess how highly qualified black students fare when they attend less rigorous colleges. If black students are mismatched – or more specifically, undermatched – into less selective schools, conventional analysis suggests that undermatching will have no effect on the graduation rates for these students. Yet this does not occur. In fact, for the most academically talented black students, a significant negative relationship exists between degree completion and attending a less selective college.

To put this association in perspective, 73 percent and 85 percent of most and moderately qualified black students, respectively, received a degree within 6-years of enrolling at the top colleges. To contrast, only 23 percent of most qualified black students and 12 percent of moderately qualified black enrollees graduated when attending the least selective universities.

Selectivity matters, especially for black students

Scalia and other affirmative action opponents have positioned the mismatch theory as central to the case against affirmative action because it creates the impression that policy changes that eliminate affirmative action would benefit black students. Nonetheless, mismatch research demonstrates that overmatched black undergraduates are far more likely to succeed in college and receive a degree when enrolled at the most selective institutions.

The trouble with ending affirmative action is that postsecondary enrollments for black undergraduates of all qualifications may cascade down to less selective colleges; however, the data show that graduation rates for all black students, regardless of academic ability, would decrease if they attended less selective institutions.

It is clear that any Supreme Court ruling that erodes affirmative action would be to the detriment of black students.

Porter received her PhD from the School of Policy, Government, and International Affairs at George Mason University.  Her research has focused on the effects of affirmative action on students entering selective colleges.  She currently works at the WIDA Consortium within the Wisconsin Center for Educational Research at the University of Wisconsin-Madison.