Opponents of school choice worry that public schools will suffer when competition is introduced.  They cite the diversion of money away from public schools and the “creaming” of the best students into private schools, leaving the neediest children even worse off than before.  But how realistic is this scenario?

A new report from the National Center for Policy Analysis marshals powerful evidence that school voucher programs do not hurt students who remain in public schools, and they may even help.

From 1998 to 2008, the Edgewood Voucher Program (EVP) offered private school tuition support to all families in the Edgewood school district, which is located in a low-income section of San Antonio, Texas.  Since EVP was privately funded, no government money was diverted from public schools.  However, large numbers of students did leave the public schools for private ones.  EVP serves as a case study, therefore, on whether public school students suffer when some of their peers transfer away.

The answer is a firm “no.”  Test scores and graduation rates went up in the Edgewood school district during the course of EVP.  Whether these gains were directly caused by EVP is difficult to ascertain, since vouchers were open to all comers rather than subject to a randomized lottery that would have provided the “gold standard” experiment.

Nonetheless, the empirical debate is over whether EVP’s effect on public schools was zero or positive.  When the progress of Edgewood public schools is compared to similar districts that had no voucher program, the data do not plausibly support any negative effect of EVP.

With school choice increasingly looking like a “no lose” proposition for private and public school students alike, will the Obama administration take notice?