CRITICS OF school choice could not contain their glee over a new study on the District’s school voucher program showing that students attending private schools did not perform as well on standardized tests as their public school counterparts. It is pretty rich that those who have railed against using test scores to hold schools accountable now invoke them to try to shut down the federally funded voucher program. And it is pretty easy for people who already have educational options for their children to discount the importance of school choice to parents who do not.

With the D.C. Opportunity Scholarship Program reauthorized by Congress this week, it is important that any assessment be complete, clear-eyed and not formed through the prism of those advancing special interests or narrow political points. What should be taken into account along with test scores is the positive difference the program has made in the lives of thousands of families, and how it and the thriving community of charter schools have enriched school choice and helped improve public education in the city.

Schools are expected to advance student achievement, and test scores are a fair metric. So the findings released last Thursday by U.S. Education Department researchers demand attention. Comparing test scores for students who received vouchers to attend private schools with those for students who applied for vouchers but didn’t receive them, the study showed significantly lower math scores for students using vouchers. Reading scores were lower for voucher students in elementary grades, but there was no difference in reading scores for older students. On the plus side, parents by a wide margin deemed the private schools safer.

The study examined student performance after only one year and so a tilt downward is not unusual, given that students are adjusting to a new environment. Previous studies have shown more promising outcomes, and data from the program administrator shows a higher level of students receiving vouchers graduating from high school than their counterparts in public schools and encouraging numbers of students with vouchers accepted to two- or four-year college. Perhaps, though, the most powerful indicator of the need for the program is the thousands of parents who put their names on waiting lists, hoping for an opportunity scholarship for their sons or daughters.

We asked Patrick J. Wolf, a University of Arkansas professor who has studied the program and served on the advisory committee of the new report, about the people behind the numbers. He described them as under-resourced families, almost all single parents with a lot of demands on their time. They are not highly educated but “value the opportunity to shape their child’s education” and “best know their child and their strengths and weaknesses.” Empowering these parents poses no threat to public education; indeed, one takeaway from the study that Mr. Wolf told us that should not be overlooked is that never before has there been such a high level of parent satisfaction with the schools — both public and private — that their children attend.