However, as Ilya Somin powerfully demonstrates, 10% plans are worse in nearly every possible respect than traditional affirmative action plans--even hard quotas. Traditional affirmative action rarely accounts for more than 20-25% of any entering class. But at the University of Texas' flagship campus, a full 71% of the class is comprised of top 10%ers. That gives almost no flexibility to admissions directors to try and find balance, admitting students who attended more rigorous schools but were not in the top 10%, or have special talents or experiences that aren't manifested in a GPA.
To be sure, this result could happen with traditional racial preferences as well. However, the ten percent plan affects a great many more admissions decisions than even the most rigid old-style affirmative action systems do. Rarely, if ever, do traditional affirmative action plans determine the admission of more than 15-20% of a school's student body. By contrast, at the University of Texas at Austin, over 70% of the student body was admitted under the ten percent plan. While some of these students would surely have gotten in anyway, it is highly likely that the ten percent plan leads to much larger sacrifices of academic merit than do racial preferences similar to those used at most other academic institutions.
Second, and probably much worse, the article notes that the formula creates perverse incentives for students to try to game the system by transferring to weaker schools or taking easier classes. While neither the article nor other evidence I have seen provides precise data on the numbers of students who do this, the effect may well be large. When I lived in Texas in 2001-2002, I met quite a few people with high school-age children who had switched to weaker schools in order to take advantage of the plan, or were considering doing so. Obviously, there is no similar perverse incentive created by traditional affirmative action. With a system of racial quotas or "plus factors," both white and minority high school students still have incentives to go to strong schools, in order to maximize their college admissions chances.
Third, the tradeoffs inherent in the ten percent plan are less transparent to both students and the general public than those involved in racial quotas. As a result, it is more likely that harmful effects will remain unmonitored and undetected. If public universities are going to strive for racial diversity, the costs and benefits of doing so should be as transparent as possible.
Finally, the ten percent plan also has the effect of disadvantaging high-achieving minority students who go to strong schools and - in part for that reason - fall short of the top ten percent in their class. Not only are these students disfavored relative to minority students attending weaker schools, they are also disfavored compared to whites in weaker schools as well.
I've noticed this dynamic in situations outside of the "10% plan." When debating the merits of the Louisville and Seattle plans, one thing that impressed me about all the "race-neutral" alternatives is that they all seemed to worsen the negative aspects of affirmative actions. Students would have to travel even further, academic standards would become less relevant, assignment would have no bearing on any remotely meritorious characteristic and would often be completely random. The only advantage was that they didn't "use" race--but yet, everyone knew they were an end-around for racial diversity as well! It's incoherent.
Of course, one could say that 10% plans have the advantage of not explicitly race-based, which might excuse them under a pure "color-blind" view. Yet, as Somin notes, you would then have to excuse not "explicitly race-based" efforts by the Jim Crow South to preserve racial hierarchy (of which there were many).
In the end, if we're going to pursue racial integration in the schools, we might as well be overt about it. It's not just more honest--it also works better for all concerned.