John Hood: Preschool intervention gets poor marks

Published 11:59 pm Tuesday, February 1, 2022

RALEIGH — Perhaps we should “follow the science” and abolish North Carolina’s pre-kindergarten program.

After all, the largest and most-sophisticated scientific evaluation ever attempted of a statewide pre-k program has just reported its latest findings — and they are damning. The pre-k program run by our neighboring state of Tennessee doesn’t just fail to accomplish its stated goal of improving academic and behavioral outcomes. It actually seems to worsen those outcomes.

That is, children who attended Tennessee’s pre-k program have lower scores and worse behavior by the time they reach the sixth grade than do otherwise comparable children who didn’t attend pre-k. “At least for poor children, it turns out that something is not better than nothing,” said one of the evaluators, Vanderbilt University professor Dale Farran. “The kinds of pre-k that our poor children are going into are not good for them long term.”

OK, then. If we abolished North Carolina’s pre-kindergarten and related programs, that would save us hundreds of millions of dollars a year while also protecting our children from potential long-term harm.

If you find my conclusion implausible and my recommendation outrageous, your brain may well be on overdrive coming up with questions about the Tennessee study’s design, validity, and relevance to North Carolina. Good for you! Readers ought to greet any sweeping claim of scientific authority with caution. A skeptical mind is a healthy mind, as long as the skepticism doesn’t dissolve into cynicism or conspiratorial thinking.

For example, you might point to previous studies that show positive associations between preschool intervention and outcome measures for at-risk students. Those studies certainly do exist, and many policymakers have found them persuasive in the past. That’s one of the main reasons North Carolina, Tennessee, and other states adopted preschool programs of various kinds over the past three decades. It’s why many progressive activists and Democratic politicians have spent years trying to enact universal pre-k nationwide, most recently as part of the Biden administration’s now-defunct Build Back Better legislation.

Nearly all prior studies, however, fall into one of two categories. The first is observational. The researchers assemble publicly available data and try to tease out the effects of preschool interventions by holding variables such as family structure and income constant and then looking for statistical correlations between, say, preschool spending and subsequent student performance.

The other, more-valuable kind of study is experimental. Researchers identify a group of needy preschoolers and then pick at random only some of those children to attend the pre-k program in question. The others comprise the control group. By tracking all the children as they proceed through school and beyond, researchers look for persistent differences between the two groups.

The multi-year Tennessee study is experimental, not observational. Two factors set it apart from prior experiments, however. One is its sheer scale. Most long-term studies of preschool intervention involve small groups of students attending a single program or set of programs. They are essentially laboratory experiments, providing interesting information but not necessarily assessing what would really happen if a promising idea were scaled up to a statewide program.

The other distinguishing factor is the Tennessee study’s recency. Some of the most-powerful findings in the preschool-intervention literature come from tiny experiments that began in the 1960s or 1970s. Both safety-net programs and the market for day care look very different today than they did back then. As Grover Whitehurst, a scholar at the Brookings Institution, once observed, “concluding that findings from these studies demonstrate that current and contemplated state pre-k programs will have similar effects is akin to believing that an expansion of the number of U.S. post offices today will spur economic development because there is some evidence that constructing post offices 50 years ago had that effect.”

Now, I don’t really think North Carolina policymakers should or will respond to the Tennessee study by abolishing our prekindergarten programs. But should we vastly expand them, as progressives routinely demand?

No. That wouldn’t be following the science.

John Hood is a John Locke Foundation board member and an author.