The latest shot fired in the battle over affirmative action in academia is a study suggesting that the end of racial preferences at law schools would cause a precipitous drop in enrollment of African Americans in law schools. The study, reported in InsiderHigherEd.com, is a response (but not exactly a refutation) of U.C. L. A. professor Richard Sander’s claim that affirmative action causes a “mismatch” of minority students and schools.

Sander showed that giving a “leg up” to some students pushed them into more competitive schools, where they didn’t do as well as they would have if they had not received the affirmative action boost. But Jesse Rothstein of Princeton and Albert H. Yoon of the University of Toronto argue differently (using pretty much the same data). They contend that many African Americans simply wouldn’t get into law school without the boost. Thus, they predict that the number of first-year students would decline by 63 per cent at all law schools and by 90 per cent in the top schools. Their paper adds fuel to the argument that affirmative action is necessary.

My take? Their analysis is static and ignores the fact that people respond to incentives. As long as affirmative action is around to give a boost, some students will work less and end up inadequately prepared. If, instead, these students knew that competition would be unleavened by preference, their actions in high school and college would change. So the Rothstein and Yoon predictions are undoubtedly too dire.