As rejection letters — and, more happily, acceptance letters — from the University of Texas begin appearing in the mailboxes and e-mail inboxes of Texas high school students, there is sure to be another round of debate about the top 10 percent law.

The top 10 percent policy is not perfect. Yes, there will be some students from elite, competitive high schools that do not get into UT — or Texas A&M — and have to choose to attend a different school. Yes, picking 10 percent as the cut-off is (somewhat) arbitrary. We can agree that the policy, to a certain degree, constrains the ability of UT to choose its matriculating class; in 2006, top 10 percenters represented 70 percent of UT's freshman class.

Many of the criticisms lofted at the program do not withstand scrutiny. We need to disabuse ourselves of the "brain drain" hypothesis — that many talented students are leaving Texas to attend college because they fall just short of the top 10 percent cut off. This criticism is based mostly on anecdotal evidence promulgated in the press. A 2006 study by Princeton University researchers in the Journal of Higher Education found no evidence to support the brain drain anecdotes. Almost invariably, the study noted, students in the top 11 percent to 20 percent of their class who specified either UT or A&M as their top choice enrolled there the following fall. Most students who enroll in out-of-state universities do so by choice, not because of the top 10 percent program.

Another study found that the top 10 percent programs encourages students from urban and rural school districts — school districts that do not generally send many of their students on to college — to see college as a realistic option and become more engaged academically in high school. So the top 10 percent program is having a positive trickle-down effect by serving as a K-12 school reform as well.

UT's data show that, once in college, top 10 percenters outperformed those admitted outside the 10 percent in virtually every objective measure, regardless of SAT or ACT scores. They drop out at lower rates, have higher grade-point averages and graduate in higher numbers. And contrary to Gov. Rick Perry's contention that "Texans see (the top 10 percent) rule as a problem," a 2005 Scripps Howard Texas poll found that 82 percent supported the top 10 percent law.

It is difficult to feel too sorry for the few privileged children who want to attend UT or A&M but are turned away to make space for a disadvantaged student with a lower SAT score. One questions what opponents of the program would put in its place. I suspect many of those who dislike the top 10 program also oppose affirmative action and agitate for a "merit-based" approach. But the top 10 percent rule is a merit-based approach. Rather than using "diversity" as a proxy for a race-based admissions process — which is, in any event, constitutional according a 2003 U.S. Supreme Court decision — the top 10 percent rule allows high-achieving students from non-traditional backgrounds a ticket which is essentially a prerequisite to success in today's world. Nor is it any more than a superficial reform to reduce the automatic admission level to, say, the top 5 percent (something that has been advocated by those opposed to the program). Those who graduate in, for example, the top 6 percent to 10 percent of their high school classes would still be left out.

The top 10 percent program is a plus for Texas. The program has positive effects on high school students in weaker public schools by making college admission a realistic opportunity. The program gives access to the two preeminent public universities in the state to students who might otherwise not have that chance. Finally, the central criticism of the program — that deserving students from good schools are not accepted and leave the state — is largely a phantom problem.

There are a lot of reasons to keep the program, and not too many reasons to do away with it.