Megan McArdle on the popular notion that preschool programs are a panacea for all that ails the public school system:
Universal preschool has become the ginseng of American politics, a sort of broad-spectrum nostrum that will cure almost anything that ails you. Inequality, male-female pay gaps, crime, poverty — just apply some early childhood programs, and watch those maladies fade. Expect to hear this a lot from Hillary Clinton in the coming presidential race.
And what kind of a crotchety, sour, greedy old columnist could be opposed to such a wonderful idea? I’m so glad you asked.
In truth, I am not opposed to early childhood education programs. I am opposed to blind boosterism of such programs, the kind that confidently predicts marvelous results from thin empirical evidence, and briskly proceeds to demand huge sums be spent accordingly. There are three big problems with this:
1. The empirical evidence is shakier than many boosters suggest. The possible benefits of these programs can be divided into two baskets: cognitive benefits (improvement in academic skills and performance), and non-cognitive benefits (improvement in such things as social skills, hyperactivity, gratification delay, and so forth). The evidence of cognitive benefits is underwhelming; they appear, and then tend to fade out as the children leave the program and proceed through our nation’s school systems.
A lot of hope has therefore been poured into non-cognitive benefits. Some early programs seem to show long-term improvements in things like graduation rates, employment and criminal activity. However, many of these programs were very small, which raises the possibility that we’re dealing with small samples plus publication bias, rather than something that actually works. In general, in social science, you tend to see that the larger the sample and the better designed the study, the less remarkable the effects. And this is definitely what you see with early childhood programs. Perry, Abecedarian, the Chicago Child-Parent Center: these are inspiring projects. They’re not nearly large enough to base a national program on.
[…]
And indeed, that’s what a new study out of Quebec seems to suggest. In the 1990s, the province instituted an inexpensive universal child-care program. The program doesn’t seem to have produced much in the way of cognitive benefits, and its non-cognitive benefits were actually negative — that is, kids exposed to the program (those who lived in Quebec) were more likely to have various problems than control groups in other provinces.
Now, this is, as I always caution, Just One Study. It’s a pretty convincing study, of a pretty large group. But it’s still a single study, which means that we should not rush to say that universal child care is a bad idea, or even that cheap, badly designed universal child care is a bad idea.
What we should rush to say, however, is that the background assumption about such programs — that at worst they’re a waste of money for zero results — cannot be safely held. We have to assume some possibility that our early childhood program will actually be worse for the kids than the status quo is.
