SACRAMENTO, CA - With the continuing inadequate performance of the public schools, it is understandable that school-choice advocates have focused on empirical studies showing the improved achievement of students in various choice programs. While the use of empirical evidence to buttress the case is important, one cannot forget that the strongest arguments for school choice are moral and philosophical.

If school-choice proponents rely too heavily on empirical studies, they risk painting themselves into a corner. For example, an influential 2002 study of a New York City private voucher program has recently come under attack from a Princeton professor and the New York Times. The critics charged that the study's conclusion, that African-American students participating in the choice program showed improved achievement, was erroneous because of methodological problems in the study. If these problems were corrected, say the critics, then no improvement occurred among the African-American students.

The critics may or may not be right. Assume, however, that they are right. If school-choice supporters have put too many of their eggs in the empirical basket, then they would be in trouble. Adverse evidence could torpedo the case for choice. Even if other empirical studies show that students in choice programs are performing better than their public-school peers, anti-choice forces are sure to muddy the waters by talking about "conflicting evidence." Muddy waters produce doubt among voters and lawmakers, making passage of choice programs less likely. That's why it's critical that choice advocates emphasize the moral and philosophical case for choice.

Last year, the Roman Catholic bishops of New York State issued a pastoral letter strongly supporting choice in education. The bishops recognized that school choice may result in improved student academic achievement, but they said: "While a system of parental choice and school competition would have a positive effect in improving schools, this argument is besides the point. The purpose of a system of parental choice is to enable parents - all parents - to exercise their inherent right and responsibility to direct the upbringing and education of their children. Even if all schools were high performing, the rationale for a system of parental choice remains. The freedom to choose the education best suited for one's children is a basic right of all parents, regardless of income."

Further, the positive effects of choice may be manifested in qualitative rather than quantitative ways. The bishops observe that "government schools do not offer the kind of values, including religious values, sought by many parents as part of their children's education." Especially in poor inner-city areas, Catholic schools' emphasis on values has resulted in better character education for children and safer learning environments.

Joe Viteritti, professor public administration at NYU and a thoughtful advocate of school choice, says that the market argument and the equity argument for choice are inextricably related. However, he says: "Of course, there are some skeptics who will continue to deny that competition, even unencumbered, with all the artificial constraints removed, will work to improve public education. I don't share their cynicism. Even if they are wrong, but especially if they are right, the most compelling argument for choice remains a plea for fairness. We don't need numbers to prove that."

Thus, regardless of what the New York Times may think, the case for school choice remains rock solid.