A recent opinion piece in The Atlanta Journal-Constitution asked, "Are vouchers a failure?" Any answer requires examining the best evidence on the topic and placing research results into a reasonable policy context.

First, the best evidence: Eighteen "gold-standard" studies followed students who were randomly offered a voucher to attend a private school and compared their outcomes with students who wanted a voucher, but were randomly denied one.

Fourteen of these studies reported positive effects from vouchers for some or all students. Two studies found no real effects, and two studies - both from Louisiana - found negative effects.

Interestingly, the Louisiana voucher program is the most regulated voucher program in the country, with significant "safeguards" and regulation of private schools. Consequently, not many children were offered choice and a large majority of private schools refused to participate in the program because they did not want to change their curriculum or other offerings in order to meet state government mandates.

The academic gains from school choice appear to be concentrated in making high school graduation more likely and further success in college, especially for disadvantaged students.

But there are social benefits from school choice programs as well, as parents who exercised choice believe their children were safer and exposed to good values in their new schools. In addition, studies find students who have received vouchers or scholarships have better virtues in terms of tolerance and civic participation.

Programs that allow parents to choose private schools also benefit public school students. Thirty-one out of 33 empirical studies find that school choice programs provide modest benefits for students who remain in public schools, according to EdChoice. (See pages 14 and 19 for a list of all studies referenced above.)

Other good surveys of the evidence regarding expanding parental choice in K-12 education have been released by the National Bureau of Economic Research and Brigham Young University Law Review.

Of the 18 "gold-standard" studies, two studies found that vouchers or scholarships did not seem to improve student test scores. What was the policy context of these findings?

The two studies analyzed scholarship programs in New York City and Toledo, Ohio, in the late 1990s. The average scholarship award in the New York program was 87 percent less than the taxpayer cost of NYC public schools: $1,400 versus $10,788.

For the Toledo program, the study authors did not report the average scholarship amounts, but today – 19 years later – awards average a mere $1,700 per student, 78 percent less than the taxpayer cost of Toledo public schools. At the time of the study, spending was $7,708, according to the ELSI tool at www.nces.ed.gov. A program that achieves the same results at 78 or even 87 percent lower cost would be deemed a smashing success, by any reasonable standard. The 14 other "gold-standard" studies, using results from five different cities, found positive effects of vouchers on students’ academic outcomes.

Parental choice programs also provide savings to state and local taxpayers. For example, the average cost of a scholarship under Georgia’s tax credit scholarship program is just under $3,900, while Georgia public schools spend over $11,200 per student. The $3,900 scholarship cost is even 22 percent less than state funding for Georgia public schools. The $11,200 figure includes federal, state and local funding.

All told, what’s the worst that can be said about expanding school choice? That it will lead to modest academic and social gains for students at a lower taxpayer cost.