It has been a rough couple of months for advocates of private and religious school vouchers.

First, voters in Utah – the reddest red state in the nation – went to the polls and trounced a voucher scheme that misguided legislators had tried to foist on them.

Then, a researcher examining Wisconsin's voucher program for children in Milwaukee determined that students in the plan are doing no better academically than their public-school counterparts. The finding is similar to other studies that have been released over the years.

Now comes a real shocker: A researcher has determined that students attending Catholic elementary schools make no more progress in reading than similar students in public schools, and they do even worse in math.

"I was actually surprised to find the results that Catholic schools are worse in mathematics," Sean F. Reardon, the study's lead author and an associate professor of education and sociology at Stanford University, told Education Week. "But, if Catholic schools aren't subject to the same accountability requirements as public schools are, then they may not spend as much time on mathematics and literacy."

For years, Catholic school boosters have bragged about these schools being superior. Parents were led to believe that if they could just get their kids into one of these coveted schools, the youngsters' test scores would soar. Federal and state lawmakers used the supposed superiority of Catholic schools as an excuse to push all kinds of voucher bills.

Reardon is an objective researcher with no axe to grind. His study sounds rock solid because he compared apples to apples by analyzing data from a federal source that tracks more than 21,000 students across the nation who entered kindergarten in fall 1998. Reardon and his research team compared those Catholic school students to public school students with similar characteristics.

Noted Education Week, "In other words, the public school students had similar baseline test scores, socioeconomic levels, and racial and ethnic backgrounds, as well as roughly the same sorts of preschool experiences and mothers with similar education levels [as the Catholic school students]."

This point is important. Previous studies have been flawed because they compared students with wildly different backgrounds and home lives. Variables unrelated to the school may explain the difference in test scores.

Studies like Reardon's have been released before. The voucher advocates have had an unusual response: They conceded that the test scores are no better at private schools but insist that the parents feel better about the schools their children are attending.

It's a rather curious argument for conservatives to make, since they love to deride liberals as "touchy and feely." I'm glad voucher parents feel good about the schools, but that won't get Johnny into college if his test scores are poor and he tanks the SATs.

Voucher boosters have promised a lot. Study after study has shown that they have failed to deliver. Nevertheless, legislators in several states are still considering voucher plans. Every one of them needs to read this new study.