James Heckman bleg

When it comes to the idea of "early intervention," and the claims that it offers very high rates of return, does he have serious published critics?


Janet Currie has a good survey of the literature in a 2001 JEP article. (blog.givewell.org/attachments/Currie.pdf) Heckman's work is more recent, though.

I'm with Eric F. above. These claims of super normal returns are based on a few small-sample, quasi-randomized studies. Why focus on these small studies (the Perry Preschool program involved 123 kids, Abecedarian had 111) and ignore the big, more relevant stuff like Head Start?

Also, yes, Heckman has revised down his earlier claims of ginormous returns to a more modest 7% or so:



Agreed, Heckman wouldn't and in practical public policy, Heckman's (and related human capital literature) is far more relevant. In part, many education researchers have been indoctrinated with "preschool doesn't work" after research focusing on test scores came out decades ago.

My kid was in early intervention, and I have no idea if it worked. He improved, but maybe it was just the result of getting older. I don't see how testing EA in any kind of provable way is feasable. IMHO the proponents of it should not harp on the rate of return and simply present it as a possibly beneficial and generally harmless program.

Heckman helped Herrnstein & Murray a lot with the manuscript for The Bell Curve, then, suddenly, wrote an angry 1995 review of The Bell Curve in Reason entitled "Cracked Bell." This review strikes many people who read it only once as a definitive debunking of Herrnstein and Murray. After all, here is this very, very smart statistician and, while it's hard to figure out exactly what he's so upset with the book about, he's clearly upset.

Heckman's distinctive personality is one of the things that helps make him a great scientist. Heckman didn't want to silence Murray, like 99% of the critics of The Bell Curve did; he wanted to PROVE HIM WRONG. And that's how science progresses. (Of course, personality is a very tricky thing -- the other critic of The Bell Curve who has contributed much to our understanding of human nature, James Flynn, is genial and suave.)

Over the years, Heckman has made some progress toward that goal, but much less than he had originally expected he would when he first attacked the book. I am told that Heckman know believes Murray was largely right and he was wrong in 1995.

That The Bell Curve has held up well is why it's so much more taboo now than it was 14 years ago (as the James Watson brouhaha showed).

In recent years, Heckman has been trying to outflank Murray by admitting that while there isn't all that much the government can do to boost the intelligence of low IQ individuals, we can and should inculcate better character in young people. The funny thing is that the judicious and philosophical Murray would have told Heckman exactly that back in 1995, and probably illustrated it with a quote from Aristotle ... if Heckman had asked him and listened to him.

But what would have been the fun of that? A lot of old things you just have to figure out for yourself -- and in the process you discover a lot of new things as well.

Whoops - I see that Eric Falkenstein pointed to a randomized control trial of Head Start. It looks interesting, and thanks for the pointer. From somebody sympathetic to the early intervention idea, I would counter his interpretation with several points:
- First, the study is *one year* of Head Start, which is in itself much less intensive than the ideals that are held up (Perry, etc). Given that the signal is 1/3 to 1/4 as strong as the more intensive interventions, it's to be expected that effects would be lost in the noise.
- Second, it looks at short term impacts (I'm not sure how EF says it has no effect after 1st grade - I don't see any data for after 1st grade). The most interesting impacts have been shown in what Heckman call "non-cognitive" behavior in the *long-term*. The study has nothing to say on that (but perhaps there will be follow-up).

Also, as a separate note, Anne Case and Angus Deaton have done some really interesting work (and tie into other interesting work) on health impacts on height & IQ. On the Woodrow Wilson School webpage.

Heckman has always advocated targeting early interventions, and not universal programs. It is also worth pointing out that programs like Perry are of a much higher quality than Head Start, so it is entirely possible for the former to have an significant effect and for the latter to mostly fail.

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