Here's a novel idea: On the question of funding a school voucher program and increasing funding for Tennessee's pre-kindergarten program, Gov. Bill Haslam and state lawmakers should let demonstrated results be their guide.

Vouchers, handled correctly, can be of great benefit to children who are trying to escape disastrous public schools.

Washington, D.C., established a voucher program in 2004 so that low-income students in badly performing public schools could attend private schools, at far lower cost than the district was spending per student in public schools.

The effort was a success. Graduation rates rose for students using vouchers compared with their counterparts in public schools. Schools were safer, and parents reported being more satisfied with their children's education. Black parents were especially fond of the program, possibly because their children otherwise were apt to be stuck in the very worst schools in the district.

Taking a cue from a successful program such as Washington's, Tennessee could develop an excellent voucher program.

Things are less clear about pre-kindergarten.

"[At] the end of the day, our mission is to figure out what's effective and what works," Haslam recently told The Associated Press.

That's the right approach.

Yet there is an unfortunate assumption that various early education programs simply must be working. After all, what could be more sensible than getting children ready for school?

But a 2011 study of Tennessee's program by the Strategic Research Group found, to put it charitably, mixed results at best. State Rep. Bill Dunn, R-Knoxville, went so far as to suggest that the program might be little more than a massive hoax perpetrated against Tennessee's taxpayers. Whether or not that is accurate, the questions surrounding the effectiveness of the program are alarming, because it is costing Tennessee $85 million per year.

More broadly, a thorough earlier study of the federal Head Start program found it to be a gargantuan waste of money.

The 2010 study by the Department of Health and Human Services found almost no social or educational benefit to children who took part in Head Start, and even those limited benefits almost entirely vanished by the time the children finished the first grade.

Despite that lack of results, U.S. taxpayers have spent around $200 billion on Head Start over more than four decades.

Tennessee can't force the federal government to stop squandering that money, but we can darn well make sure we don't follow suit. If the state program isn't producing verifiable, significant and sustained results, it most assuredly shouldn't be getting a funding increase.