How does class-size reduction compare with school vouchers? It's a question that we can answer with surprising clarity thanks to a growing body of research.
Princeton University researcher Cecilia Rouse, whose findings have been cited by voucher supporters, conducted a study in 1998 comparing Milwaukee's voucher schools with the city's P-5 schools-public schools with small class sizes and additional targeted funding (similar to SAGE). "The results suggest," Rouse concluded, "that students in P-5 schools have math test score gains similar to those in the [voucher] schools, and that students in the P-5 schools outperform students in the [voucher] schools in reading." Rouse went on to explain: "Given that the pupil-teacher ratios in the P-5 and [voucher] schools are significantly smaller than those in the other public schools, one potential explanation for these results is that students perform well in schools with smaller class sizes [emphasis in original]."40 In other words, improved test scores for some voucher students may have been the result of attending smaller classes.
Princeton University researchers Alan Krueger and Diane Whitmore compared the effect of attending a smaller class to the effect of receiving a private-school voucher. Despite the serious questions raised about the Peterson team's August 2000 voucher study, Krueger and Whitmore used the study's data on African-American voucher students for the sake of comparison. (Keep in mind, in the August 2000 study African-Americans were the only subgroup of voucher students who showed significant gains.) Even in this context, Krueger and Whitmore found that black students who had attended small classes "improved their test performance by around 50 percent more than the gain experienced by black students who attended a private school as a result of receiving a voucher …"41
Although, in statistical terms, class size doesn't emerge as a determining factor in the African-American gains cited in Peterson-Howell's three-year evaluation of voucher students, it is clear that these voucher students were in smaller schools with smaller class sizes, and more after-school and tutorial programs.42
Indeed, this is a powerful irony. The African-American voucher students were learning in the very educational climate that many policy analysts have long sought for public schools- a climate that is incredibly difficult to create when a state diverts substantial tax dollars to vouchers.