A thought on universal Pre-K

2/16/2013 07:27:00 PM
As Matthew Yglesias notes, Obama didn't quite endorse universal per-kindergarten, but came close. This prompted a slurry of debate on the subject across the econosphere. To summarize the state of the research--its pretty clear that "head start" type programs improve student performance for the first few grades of elementary school. Then the results start to diverge. Some studies from randomized trials found that by third grade, the effect of pre-k programs completely disappeared. Other longer-term studies found that in later cohorts, the benefits of pre-k remained persistent in many subjects, like math, beyond fourth grade. And still a third branch of research pioneered by James Heckman (a name that is definitely to be taken seriously) finds all kinds of later-in-life benefits including reduced incarceration rates and better career attainment--so much so, in fact, that the program more than pays for itself (perhaps this is overstating the Heckman result, see Heckman's comments here).

Yglesias appears not to buy the optimistic findings of Heckman and his crew. Or at the very least, doesn't find their results highly generalizable. So here is a question that should help clarify the policy question: Should we offer universal kindergarten?

My point is that pre-k is different from k-12 education only by social convention. A better question than whether to enact universal pre-k is simply to ask what is the optimal age to start education? If pre-k is not worthwhile, as Yglesias suspects, then it is that much more likely that kindergarten is also not worthwhile--the two are, after all, only one year apart. And of course, if kindergarten is not worthwhile, then we need to ask whether first grade is either.

So, the real question has little to do with pre-k. What we are really after is the optimal age at which to start school. People who argue against pre-k are, more often than not, making a much more specific argument than they think they are, since to the extent they don't support abolishing Kindergarten they are really saying that they believe there is some inherent reason that 5 years old, not 4, happens to be the exact optimal age to start school--I guess we just lucked out on that one.