Will vouchers help improve non-voucher schools as well? Opponents of vouchers say no, but a recent study says yes:

…we find that schools that received a grade of “F” in summer 2002 immediately improved the test scores of the next cohort of students, and that these test score improvements were not transitory, but rather remained in the longer term. We also find that “F”-graded schools engaged in systematically different changes in instructional policies and practices as a consequence of school accountability pressure, and that these policy changes may explain a significant share of the test score improvements (in some subject areas) associated with “F”-grade receipt.

Economist Alex Tabarrok summarizes the findings thusly:

Thus, this paper shows two things. First, that the test scores of the students in the public schools improved when vouchers gave the schools better incentives to perform. Second, at least some of the improvement comes from changes in how students are taught.

What did the schools do differently you ask?

…we find that schools receiving an “F” grade are more likely to focus on low-performing students, lengthen the amount of time devoted to instruction, adopt different ways to organize the day and learning environment of the students and teachers, increase resources available to teachers…

It is not true that “nothing can be done to improve the schools.” Incentives matter.

The full link can be found here.