The name Raj Chetty has been coming up a great deal lately, like a bad burrito that resists easy digestion. A great deal has been written about Chetty and his scholarly work, much of it by other scholars in various states of apoplexy.My goal today is not to contribute to that scholarly literature, but to try to translate the mass of writing by various erudite economists, scholars and statisticians into something shorter and simpler than ordinary civilians can understand.
In other words, I'm going to try to come up with a plain answer for the question, "Who is Raj Chetty, what does he say, how much of it is baloney, and why does anybody care?"
Who is Raj Chetty?
Chetty immigrated to the US from New Delhi at age nine. By age 23 he was an associate professor of economics at UC Berkeley, receiving tenure at at age 27. At 30, he returned to his alma mater and became the Bloomberg Professor of Economics at Harvard.
He has since become a bit of a celebrity economist, consulted and quoted by the President and members of Congress. He has won the John Bates Clark Medal; Fortune put him on their list of influential people under forty in business.
Chetty started attracting attention late in 2010 with the pre-announcement of a publication of research that would give a serious shot in the arm to the Valued Added Measurement movement in teacher evaluation. His work has also made special appearances in the State of the Union address and the Vergara trial.
What does Chetty say?
The sexy headline version of Chetty is that a child who has a great kindergarten teacher will make more money as an adult.
The unsexy version isn't much more complicated than that. What Chetty et al (he has a pair of co-authors on the study) say is that a high-VAM teacher can raise tests scores in younger students (say, K-4) and while that effect will disappear around 8th grade, eventually those VAM-exposed children will start making bigger bucks as adults.
Implications? Well, as one of Chetty's co-authors told the New York Times--
“The message is to fire people sooner rather than later,” Professor Friedman said.
Chetty's work has been used to buttress the folks who believe in firing our way to excellence-- just keep collecting VAM scores and ditching the bottom 5% of your staff. Chetty also plays well in court cases like Vergara, where it can be used to create the appearance of concrete damage to students (if Chris has Mrs. McUnvammy for first grade, Chris will be condemned to poverty in adulthood, ergo the state has an obligation to fire Mrs. McUnvammy toot suite). You can read one of the full versions of the paper here.
Who disagrees with Chetty?
Not everybody. In particular, economist Eric Hanushek has tried to join this little cottage industry, and lots of reformy poicy makers love to quote his study.
But the list of Chetty naysayers is certainly not short. Chetty appears to evoke a rather personal reaction from some folks, who characterize him as everything from a self-important twit to a clueless scientist who doesn't understand that he's building bombs that blow up real humans. I've never met the man, and nothing in his writing suggests a particular personality to me. So let's just focus on his work.
Moshe Adler at Columbia University wrote a research response to Chetty's paper for NEPC. This provoked a response from Chetty et al, which provoked yet another response from Adler. You can read the whole conversation here, but I'll warn you right now that you're not going to just scan it over lunch.
Meanwhile, you'll recall that the American Statistical Association came out pretty strongly opposed to VAM, which also put them in the position of being critical-- directly and indirectly-- of Chetty. Chetty et al took it upon themselves to deliver the ASA a lesson in statistical analyses ("I will keep my mouth shut because these people are authorities in areas outside my expertise," is apparently really hard for economists to say) which led to a conversation recounted here.
What do the scholarly and expert critics say?
To begin with, the study has a somewhat checkered publication history, debuting as news blurbs in 2010 and making its way up to publication in a non-peer-reviewed journal, then to republishing as two articles, then in a peer-reviewed journal. That history, along with many criticisms of the study, can be found here at
I wold bet you dollars to donuts that we could perform research that would "prove" that eating a good breakfast when you're six, or having a nice pair of shoes when you're ten, can also be linked to higher-paying jobs in adulthood. As it is, we have "proof" that Nicholas Cage causes death by drowning, and that margarine causes divorce in Maine.
Chetty's work is not going to go away because it's sexy, it's simple, and it supports a whole host of policy ideas that people are already trying to push. But it is proof positive that just because somebody teaches at Harvard and wins awards, that doesn't mean they can't produce "research" that is absolute baloney.
Thanks- this is very helpful :)ReplyDelete
Thanks- this is very helpful :)ReplyDelete
The real hideous assumption is that the marginally higher income that is seen in one snapshot is the paramount measure of value in a person's life. Even if I were to accept that some teachers will induce students to earn slightly more, it gives me no useful policy guidance. I can suppose there are teachers that inspire students to embark on careers that are slightly less remunerative but more personally rewarding. Or I can wonder if the lower earners nevertheless have more free time and higher net worth due to better personal management skills. The Chetty study turns humans into beasts measured by money, and even at that is inconclusive. It's crap.ReplyDelete
Great post. Thanks!ReplyDelete