Interview of Joshua Angrist: On charter schools, the elite illusion, and the “Stones Age” of econometrics

Nice interview of Prof Joshua Angrist of MIT:

As a teenager growing up in Pittsburgh, Joshua Angrist became fed up with high school and said his goodbyes to it after his junior year. Today, at the Massachusetts Institute of Technology, he’s a top researcher in labor economics and the economics of education — with work that includes a series of famed studies of policy choices for K-12 schooling.

Much of his work has been based on ingenious “natural experiments,” that is, episodes in which two or more groups of people were randomly exposed to different policies or different experiences. Such occurrences are an opportunity for Angrist and his co-authors to use the tools of econometrics to assess the effects of those differences — whether that’s a large classroom versus a small classroom or education at a charter school versus education at a conventional public school.

Angrist’s first natural experiment looked at labor market outcomes for men who were drafted during the Vietnam War era compared with those of men who weren’t drafted. The idea came to him from his labor economics teacher and Ph.D. adviser at Princeton, Orley Ashenfelter, who mentioned in class one day that he had seen a news article about a study in the New England Journal of Medicine in which epidemiologists investigated the long-term health effects of being drafted.

“They had done this very clever thing where they used the fact that draft lottery numbers were randomly assigned,” Angrist remembers, “and they compared people who had high and low numbers to test the causal effects.”

Ashenfelter remarked to the class that this use of the draft lottery was a great idea and that somebody should use it to look at the effects of the draft on the men’s earnings. Angrist agreed; immediately after class, he went to the library to start the research that became his doctoral thesis.

Angrist found that in the early 1980s, well after the end of the war, veterans — whether they served in Vietnam or elsewhere — took an earnings hit of around 15 percent compared with non-veterans in the same period. (Angrist himself served as a paratrooper in the Israeli army before he went to grad school.)

In addition to his research and teaching responsibilities at MIT, Angrist is a co-founder and co-director of MIT’s School Effectiveness and Inequality Initiative. He is the author, with Jörn-Steffen Pischke, of the econometrics textbooks Mostly Harmless Econometrics: An Empiricist’s Companion (2009) and, for undergraduates, Mastering ‘Metrics: The Path from Cause to Effect (2015). He also teaches econometrics in a series of free videos offered through the nonprofit Marginal Revolution University.

How he came into economics? It is all about getting one good teacher!

 You left high school early and then took a while to decide to go to college. Why?

Angrist: I wasn’t a very good high school student. I didn’t pay much attention to school, and I didn’t go very often. I also liked to work because I wanted money. So I started working as a busboy, and I liked having money because money is good when you’re a teenager. Then I thought, well, I’ll just leave school if I can and go work full time.

I figured out that the Pennsylvania high school graduation requirements were pretty minimal. So I was able to graduate with a bare bones diploma after my junior year. Then I worked for a while, mostly in institutions for the intellectually disabled because I had experience with this kind of work at summer camp. But from my work experience, I realized I should probably go to college.

EF: Was there anything in particular that brought home to you the idea that you should go to college?

Angrist: I saw that the work was not that interesting. And it wasn’t clear where it would lead. So I got bored.

EF: At some point, you became interested in economics. How did that happen?

Angrist: Because of the work I’d been doing, I thought I would go into special education, so I took a psych course. But I also took Econ 101, and I had a wonderful economics teacher, a man named Bob Piron. At least he was very much to my taste. He was funny. He was provocative. He would call on people; he would tease people. Today, I suppose he would get fired for this, but as a teacher, I try to do a version of what he did that’s a little more in tune with the times.

Piron was clear as a bell, and he was challenging, and I just enjoyed the whole thing. So I thought, I want more of this. I guess there was also the fact that I did like the material and I had an affinity for it. I started taking all the econ I could get and all the math I could stomach.

I also experienced another example of the power of having good teachers. Oberlin, where I went, is a small liberal arts college. It has a good economics department and they invite their best seniors to write a thesis, so I did it. What Oberlin does that’s very nice is they invite an outside examiner, somebody who is a well-known researcher. They invited Orley Ashenfelter, a labor economist at Princeton.

Not everybody wants to come to Oberlin for a few days, but Orley did that; he’s that kind of person. I met him and got to know him a little bit and he took a shine to me, I was lucky, and he said, “Why don’t you come to Princeton?” So after I graduated from Oberlin and after my Israeli army service, I went to graduate school at Princeton because of him and to work with him.

On Stone age econometrics:

EF: You’ve co-authored two econometrics texts and you teach the subject online through Marginal Revolution University. You’ve written that you “hope to bring undergraduate econometrics instruction out of the Stones Age.” What did you mean by that?

Angrist: That comes from an article Steve Pischke and I wrote. Steve is my co-author on the books and an old friend of mine. Steve and I noticed that the way econometrics is taught is divorced from the way modern empirical work is carried out. The conventional econometrics course devotes a lot of time to things that aren’t very important, like heteroskedasticity and generalized least squares, and little or even no time to questions of research design, how to figure out whether something affects something — in other words, causality — and how you should interpret regression estimates. Steve and I tackled that in our graduate book, Mostly Harmless Econometrics, and we followed up in Mastering ‘Metrics for undergrads.

The Stones Age idea is that the Stones are an awesome band, but their heyday was the ’70s. And even though modern empirical econometric research looks nothing like 1970s econometrics, econometrics instruction for the most part looks just like it looked in 1975.

Lots of other ideas…

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