Pushing New Ideas (Guido Imbens, Josh Angrist, Isaiah Andrews)

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- [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.

At the time, did you feel like
you are 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...?

Not so much that it was
a whole line of work,

but certainly I felt like,
"Wow, this--"

- [Josh] We proved something
that people didn't know before,

that it was worth knowing.

Yeah, going back compared to
my job market papers having--

I felt this was actually
a very clear crisp result.

But there were definitely
was mixed reception

and I don't think anybody
said that,

"Oh, wow, this is already,
something."

No, 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 were 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 Ruben

and he was like,
"Yeah, 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.

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- [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 was 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 it 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 what
we think it's good now

we might not have loved it
at the time.

I remember being somewhat,
the 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'd 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
the paper is wrong

but it's saying that

it's a disservice
to the profession,

that's not really--

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."

Right, 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 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 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 [did] 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.

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- [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 well, 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 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're talking about
the draft lottery paper.

We were talking about "never takes"

[as people who wound 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 [out of hand 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 actually thinking
about 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

and rather than dismissing
and say,

"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.

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- [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.

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