In a new survey paper (pdf), Greg Duncan and Katherine Magnuson report:
Programs beginning before 1980 produced significantly larger effect sizes (.33 standard deviations) than those that began later (.16 standard deviations). Declining effect sizes over time are disappointing, as we might hope that lessons from prior evaluations and advances in the science of child development would have led to an increase in program effects over time. However, the likely reason for the decline is that counterfactual conditions for children in the control groups in these studies have improved substantially. We have already seen in Figure 1 how much more likely low-income children are to be attending some form of center-based care now relative to 40 years ago. This matters because, though center-based care programs have varying degrees of educational focus, most research suggests that center-based care is associated with better cognitive and achievement outcomes for preschool age children (NICHD Early Childcare Research Network and Duncan 2003).
Even more impressive are gains in the likely quality of the home environment provided by low-income mothers, as indexed by their completed schooling. In 1970, some 71 percent of preschool age children in the bottom 20 percent of the income distribution had mothers who lacked a high school degree, while only 5 percent of the mothers had attended at least some postsecondary schooling…
There is also this:
Analysis of the meta-analytic database shows that, taken as a whole, effect sizes were neither larger nor smaller for children who started programs at younger ages (Leak, Duncan, Li, Magnuson, Schindler, and Yoshikawa 2012). This suggests that other modes of early childhood investments—for example, home visitation for high-risk, first-time mothers (Olds, Sadler, and Kitzman 2007) or developmental screenings and interventions for children living in families with documented domestic violence—may be more-effective ways of building children’s capacities during the very early years of life.
It would be a mistake, however, to read the authors as simply trashing pre-school programs. Part of their close emphasizes this question:
This finding raises a puzzle: How do we reconcile the fade-out of preschool program impacts on test scores during elementary school with the evidence showing that such programs nonetheless have beneficial impacts on a broad set of later-life outcomes like high school graduation rates, teen parenthood, and criminality?
It is an interesting essay which raises good questions throughout.
Is it effective at babysitting kids?
They’re not at home.
Point proved. Where’s my grant?
It is not just babysitting if it has “evidence showing that such programs nonetheless have beneficial impacts on a broad set of later-life outcomes like high school graduation rates, teen parenthood, and criminality”. Indeed, in my state of California where prison populations are a major burden, that is pretty important.
Is there actually causation or is it just the obvious correlation?
Better parents will tend to take advantage of pre-school programs which require at least a little bit of effort to get into and get their kids to in the morning. Worse parents will just feed their kids Mountain Dew and Dorritos and let the TV babysit them.
Yes. There were a couple lectures (2 researchers) and some papers in Dan Ariely’s Coursera MOOC on irrationality which covered this area. The claim was that preschool taught self-control and deferred gratification. It basically improves passes on the marshmallow experiment, and you get the benefit of better marshmallow patience later in life. (Simplifying.)
There is no such evidence – the “studies” are pure crap – sociological advocacy, not science.
And this is why the idea, heavily promoted by James Heckman among others, that old programs like the Perry preschool would produce similar results today is silly.
Tyler should have quoted this whole paragraph:
In 1970, some 71 percent of preschool age children in the bottom 20 percent of the income distribution had mothers who lacked a high school degree, while only 5 percent of the mothers had attended at least some postsecondary schooling (based on authors’ calculation of the October Current Population Survey data). By 2000, the corresponding percentage of children with mothers who did not have a high school degree had dropped by nearly half (to 37 percent), while the percentage with mothers who had completed some postsecondary schooling increased five-fold (to just over 25 percent).
The idea that pre-school could help kids is silly because more the of the moms have more education? About 1/3 of U.S. high school graduates are functionally illiterate.
What is silly is to assume that the conditions of today’s lower class Americans are identical to those of their counterparts 50 years ago, and that what worked then would work in just the same way today.
I quoted that paragraph because Tyler (accidentally?) chopped it, leaving out the relevant comparison. I was not trying to make a specific point about rising education levels, although that’s of course one important difference between today and the 1960s.
Yes, this does look like a confounding factor that would, potentially, explain the result. In short, it could be that preschool can help mitigate the negative effects of parents with low education, and with parents of higher education, the effect shrinks.
Another factor, emphasized in the paper (Figure 1), is that a much larger percentage of all children, regardless of socioeconomic background, attends preschool nowadays than a few decades ago.
Smarter moms with smarter offspring utilize daycare now because they’ve entered the workforce instead of staying home with their children. (Daycare was for the proles who needed two incomes to make it.) Later, the smarter offspring with smarter parents have better life outcomes.
Trying to tie pre-school into all this is just the continuous mantra of pushing the crucial age of early intervention back to pre-natal 8 months and 29 days, but not a day earlier!
Actually, pre-conception nutrition might be important, and possibly crucial.
Really, nothing less than making sure a disadvantaged embryo is implanted in a proper, privileged uterus will do.
Just think how smart Einstein would have been if his mom had a nutritionist and a personal trainer. He’d be like … god or something.
“This finding raises a puzzle: How do we reconcile the fade-out of preschool program impacts on test scores during elementary school with the evidence showing that such programs nonetheless have beneficial impacts on a broad set of later-life outcomes like high school graduation rates, teen parenthood, and criminality?”
Here’s a theory – if the effect of pre-school on long-term life outcomes is relatively constant while the effect of pre-school on elementary-school test scores are not, perhaps the thing that is changing is not “the effect of pre-school” but simply something relating to the composition or context of elementary-school tests.
Here’s an simpler theory – the “evidence” that pre-school leads to better outcomes in adulthood is of no scientific value – ie, it’s utter crap. Have you seen those studies? They’re advocacy, not studies. The outcomes were not pre-selected for study, but developed post hoc, cherry-picked to give the best result.
Diminishing returns to marginal expansion? The early adopters do so rationally. Follow-ons do so rationally, but only after subsidies are added due to normative bias and equality initiatives.
Anyway, I talked to Occam and he said maybe we don’t know anything yet.
You obviously talked to Occam’s impostor, because the real Occam would have explained to you that the obvious explanation is that the evidence for positive adulthood effects has no scientific basis, but is based on so-called “studies” that are in fact advocacy by the left-wing sociologists making the claims.
Isn’t this another aspect of The Great Stagnation?
The low hanging fruit of educating the children of uneducated parents has disappeared as the average education level of parents has increased.
After the latest pre-pre-school hopes fade as the data pile up, the next frontier for Closing the Gap will become pre-natal care. A generation from now, everybody will be convinced that the cause of differences in test scores can be fixed during the 8 months and 29 days before birth.
But not a day earlier!
Maybe it’s educational TV.
Argh, the HBD people and the Red Pill people are insufferable when they comment on mainstream blogs with their in-jokes and little references and sayings, never defining any of it for the rest of us.
Steve Sailer and Anti-Gnostic, since you both made basically the exact same sarcastic post, without defining it: would you guys mind explaining what you mean by “the 8 months and 29 days before birth, but not a day earlier”?
They are implying that a big part of the gap between low-income and high-income kids is hereditary/genetic, and therefore much of it will never close. Over time, interventions intended to “close the gap” have gotten earlier and earlier, so the joke is that eventually prenatal conditions will be blamed for the gap, since no one will be willing to accept the gap is due to hereditary factors.
Dear brian h.:
Only bad people understand jokes. By demonstrating that you understand the joke, you are bad. In contrast, good people are, by definition, humorless and obtuse.
Steve
As the authors note, it is indeed quite a puzzle how pre-school education could possibly not show positive effects during schooling, yet have dramatically positive effects in adulthood. But if you look at the studies that find no effect during early schooling, you’ll find them very dense with objective facts such as testing results, etc. But if you look at those handful of studies purporting to show dramatic adulthood outcomes, you don’t find a lot of such data. In fact these latter studies aren’t scientific – they’re advocacy. They didn’t come up with rigorously selected criteria prior to pre-school to evaluate the outcomes, but instead retrospectively identified metrics to compare the control groups, leaving much room for post-hoc cherry-picking. The most parsimonious explanation of the paradox is that the adulthood-effects studies are flawed, and aren’t actually showing any real positive outcomes from pre-school.
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