♪ [music] ♪
- [Narrator] Welcome to Nobel Conversations.
In this episode, Josh Angrist and Guido Imbens,
sit down with Isaiah Andrews
to discuss how their research was initially received
and how they responded to criticism.
- [Isaiah] At the time, did you feel like
you were on to something,
you felt this was the beginning of a whole line of work
that you felt like was going to be important or...?
- [Guido] Not so much that it was a whole line of work,
but certainly I felt like, "Wow, this--"
- [Josh] We've proved something we didn't know before,
that it was worth knowing.
- Yeah, going back to the...
compared to my job market paper or something--
No, I felt this was actually a very clear, crisp result.
- But there was definitely a mixed reception
and I don't think anybody said that,
"Oh, well, this is already something
which is the nightmare scenario for a researcher
where you think you've discovered something
and then somebody else says, "Oh, I knew that."
But there definitely was a need to convince people
that this was worth knowing, that instrumental variables
estimates a causal effect for compliers.
- Yeah, but even though it took a long time
to convince a bigger audience,
sometimes even fairly quickly, the reception was pretty good
among a small group of people.
Gary clearly liked it a lot from the beginning,
and I remember...
because at that point Josh had left for Israel,
but I remember explaining it to Don Rubin,
and he was like, "You know, this really is something here."
- Not right away though.
Don took some convincing.
By the time you got to Don,
there have been some back and forth with him
and in correspondence, actually.
- But I remember at some point getting a call or email from him
saying that he was sitting at the airport in Rome
and looking at the paper and thinking,
"Yeah, no actually, you guys are onto something."
- We were happy about that.
But that took longer than I think you remember.
It wasn't right away.
[laughter]
Because I know that I was back in Israel
by the time that happened.
I'd left for Israel in the summer of--
I was only at Harvard for two years.
We had that one year.
It is remarkable, I mean, that one year was so fateful for us.
- [Guido] Yes.
I think we understood there was something good happening,
but maybe we didn't think it was life-changing, only in retrospect.
♪ [music] ♪
- [Isaiah] As you said, it sounds like a small group of people
were initially quite receptive,
perhaps took some time for a broader group of people
to come around to seeing the LATE framework
as a valuable way to look at the world.
I guess, in over the course of that,
were their periods where you thought,
maybe the people saying this wasn't a useful way
to look at the world were right?
Did you get discouraged? How did you think about?
- I don't think I was discouraged,
but the people who were saying that we're smart people,
well-informed econometricians,
sophisticated readers,
and I think the substance of the comment
was this is not what econometrics is about.
Econometrics being transmitted at that time was about structure.
There was this idea that there's structure in the economy,
and it's our job to discover it,
and what makes its structure is it's essentially invariant.
And so we're saying, in the LATE theorem,
that every instrument produces its own causal effect,
which is in contradiction to that to some extent,
and so that was where the tension was.
People didn't want to give up that idea.
- Yeah, I remember once people were started
arguing more vocally against that,
that never really bothered me that much.
It seemed clear that we had a result there,
and it became somewhat controversial,
but controversial in a good way.
It was clear that people felt
they had to come out against it because--
- Well, I think we think it's good now.
We might not have loved it at the time.
I remember being somewhat more upset--
there was some dinner where someone said,
"No, no, no, that paper with Josh --
that was doing a disservice to the profession."
- We definitely had reactions like that.
- At some level, that may be indicative of the culture
in general in economics at the time.
I thought back later, what if that happened now?
If I was a senior person sitting in that conversation,
I would call that out because it really was not appropriate--
- [Josh] It wasn't so bad.
I think the criticism is...
It wasn't completely misguided.
It was maybe wrong.
No, no, but you can say that paper is wrong,
but it's saying that
it's a disservice to the profession --
- that's not really-- - [Isaiah] It's a bit personal.
- Yes, and doing that not to me
but in front of my senior colleagues.
- But nobody was saying the result was wrong,
and I remember also,
some of the comments were thought-provoking.
So we had some negative reviews,
I think, on the average causal response paper.
Somebody said, "These compliers, you can't figure out who they are."
It's one thing to say you're estimating
the effect of treatment on the treated
or something like that.
You can tell me who's treated
people in the CPS, you can't tell me who's a complier.
So that was a legitimate challenge.
- That's certainly fair, and I can see why
that part made people a little uneasy and uncomfortable.
But at the same time,
because it showed that you couldn't really go beyond that,
it was a very useful thing to realize.
I remember on the day we got to the key result
that I was thinking, "Wow, this is as good as it gets.
Here we actually have an insight, but it clearly--"
- And we had to sell it at some point.
For quite a few years, we had to sell it,
and it's proven to be quite useful.
I don't think we understood that it would be so useful at the time.
- No.
- I did feel early on this was a substantial insight.
- [Josh] Yeah we'd done something.
- But I did not think goals were there.
- I don't think we were aiming for the Nobel.
[laughter]
We were very happy to get that note in Econometrica.
♪ [music] ♪
- [Isaiah] Are there factors or are ways of approaching problems
that lead people to be better at recognizing the good stuff
and taking the time to do it as opposed to dismissing it?
- [Josh] Sometimes I think it's helpful.
If you're trying to convince somebody
that you have something useful to say
and maybe they don't speak your language,
you might need to learn their language.
- Yes, yes, exactly.
- That's what we did with Don, we figured out how to--
I remember we had a very hard time
explaining the exclusion restriction to Don,
maybe rightfully so,
I think Guido and I eventually figured out
that it wasn't formulated very clearly,
and we came up with a way to do that
in the potential outcomes framework
that I think worked for the three of us.
- [Guido] Yeah.
Well, it worked for the bigger literature,
but I think what you're saying there is exactly right,
you need to figure out how not just say,
"Okay, I've got this language, and this this works great,
and I've got to convince someone else to use the language.
You could first figure out what language they're using,
and then, only then, can you try to say,
"Well, but here you're thinking of it this way."
But that's actually a pretty hard thing to do.
You get someone from a different discipline,
convincing them, two junior faculty in a different department
actually have something to say to you
that takes a fair amount of effort.
- Yeah, I wrote Don a number of times,
in fairly long letters.
I remember thinking this is worth doing,
that if I could convince Don,
that would validate the framework to some extent.
- I think both you and Don
were a little bit more confident that you were right.
- Well, we used to argue a lot,
and you would sometimes referee those.
[laughter]
That was fun.
It wasn't hurtful.
- I remember it getting a little testy once.
We had lunch in The Faculty Club,
and we were talking about the draft lottery paper.
We were talking about "never takes"
as people wouldn't serve in the military
irrespective of whether they were getting drafted,
and you or Don said something
about shooting yourself in the foot...
[laughter]
...as a way of getting out of the military
and that may be the exclusion restriction
for never takes wasn't working,
and then the other one was going,
"Well, yes, you could do that,
but why would you want to shoot yourself in the foot?"
[laughter]
It got a little there...
- I usually go for moving to Canada for my example,
when I'm teaching that.
[laughter]
But things are tricky,
I get students coming from Computer Science,
and they want to do things on causal inference,
and it takes a huge amount of effort to figure out
how they're actually thinking about a problem
and whether there's something there.
And so, now over the years,
I've got a little more appreciation for the fact
that Don was actually willing to--
It took him a while, but he did engage first with Josh
and then with both of us,
rather than dismissing and saying,
"Okay, well, I can't figure out what these guys are doing,
and it's probably just not really that interesting."
- Everybody always wants to figure out quickly.
You want to save time,
and you want to save your brain cells
for other things.
The fastest route to that is to figure out
why you should dismiss something.
- Yes.
- I don't need to spend time on this.
♪ [music] ♪
- [Narrator] If you'd like to watch more Nobel Conversations,
click here,
or if you'd like to learn more about econometrics,
check out Josh's Mastering Econometrics series.
If you'd like to learn more about Guido, Josh, and Isaiah,
check out the links in the description.
♪ [music] ♪