WEBVTT 00:00:00.130 --> 00:00:02.200 ♪ [music] ♪ 00:00:03.645 --> 00:00:05.600 - [Narrator] Welcome to Nobel Conversations. 00:00:07.250 --> 00:00:10.240 In this episode, Josh Angrist and Guido Imbens 00:00:10.240 --> 00:00:11.920 sit down with Isaiah Andrews 00:00:11.920 --> 00:00:14.303 to discuss how their research was initially received 00:00:14.999 --> 00:00:17.090 and how they responded to criticism. 00:00:18.700 --> 00:00:20.380 - [Isaiah] At the time, did you feel like 00:00:20.380 --> 00:00:21.627 you were on to something, 00:00:21.627 --> 00:00:25.152 you felt this was the beginning of a whole line of work 00:00:25.152 --> 00:00:27.202 that you felt like was going to be important or...? 00:00:27.600 --> 00:00:30.000 - [Guido] Not so much that it was a whole line of work, 00:00:30.000 --> 00:00:31.894 but certainly, I felt like, "Wow, this --" 00:00:32.277 --> 00:00:35.045 - [Josh] We've proved something we didn't know before, 00:00:35.045 --> 00:00:36.114 that it was worth knowing. 00:00:36.114 --> 00:00:38.033 - Yeah, going back to the... 00:00:38.741 --> 00:00:41.080 compared to my job market paper or something -- 00:00:41.080 --> 00:00:45.560 No, I felt this was actually a very clear, crisp result. 00:00:46.400 --> 00:00:49.657 - But there was definitely a mixed reception, 00:00:49.657 --> 00:00:52.420 and I don't think anybody said that, 00:00:52.420 --> 00:00:55.487 "Oh, well, this is already something 00:00:56.043 --> 00:00:59.386 which is the nightmare scenario for a researcher, 00:01:00.230 --> 00:01:02.003 where you think you've discovered something 00:01:02.003 --> 00:01:04.461 and then somebody else says, 'Oh, I knew that.'" 00:01:05.000 --> 00:01:07.220 But there definitely was a need to convince people 00:01:07.220 --> 00:01:10.370 that this was worth knowing, that instrumental variables 00:01:10.370 --> 00:01:12.687 estimates a causal effect for compliers. 00:01:13.200 --> 00:01:16.178 - Yeah, but even though it took a long time 00:01:16.178 --> 00:01:19.348 to convince a bigger audience, 00:01:19.820 --> 00:01:24.346 sometimes even fairly quickly, the reception was pretty good 00:01:24.800 --> 00:01:26.645 among a small group of people. 00:01:27.200 --> 00:01:31.297 Gary clearly liked it a lot from the beginning, 00:01:31.800 --> 00:01:33.289 and I remember... 00:01:33.289 --> 00:01:35.645 because at that point Josh had left for Israel, 00:01:35.645 --> 00:01:38.886 but I remember explaining it to Don Rubin, 00:01:39.696 --> 00:01:43.700 and he was like, "You know, this really is something here." 00:01:43.700 --> 00:01:45.197 - Not right away though. 00:01:45.932 --> 00:01:47.173 Don took some convincing. 00:01:47.500 --> 00:01:49.150 By the time you got to Don, 00:01:49.150 --> 00:01:51.226 there have been some back and forth with him 00:01:51.226 --> 00:01:53.304 and in correspondence, actually. 00:01:53.700 --> 00:01:57.103 - But I remember at some point getting a call or email from him 00:01:57.103 --> 00:02:00.020 saying that he was sitting at the airport in Rome 00:02:00.020 --> 00:02:03.700 and looking at the paper and thinking, 00:02:03.700 --> 00:02:07.000 "Yeah, no, actually, you guys are onto something." 00:02:07.490 --> 00:02:08.594 - We were happy about that. 00:02:08.594 --> 00:02:10.550 But that took longer than I think you remember. 00:02:11.030 --> 00:02:12.500 It wasn't right away. 00:02:12.500 --> 00:02:13.700 [laughter] 00:02:13.700 --> 00:02:15.325 Because I know that I was back in Israel 00:02:15.325 --> 00:02:16.627 by the time that happened. 00:02:16.627 --> 00:02:18.750 I'd left for Israel in the summer of -- 00:02:19.390 --> 00:02:21.190 I was only at Harvard for two years. 00:02:21.190 --> 00:02:22.540 We had that one year. 00:02:22.540 --> 00:02:25.700 It is remarkable, I mean, that one year was so fateful for us. 00:02:25.900 --> 00:02:27.200 - [Guido] Yes. 00:02:27.690 --> 00:02:30.200 I think we understood there was something good happening, 00:02:30.200 --> 00:02:33.700 but maybe we didn't think it was life-changing, only in retrospect. 00:02:33.700 --> 00:02:35.620 ♪ [music] ♪ 00:02:35.620 --> 00:02:37.495 - [Isaiah] As you said, it sounds like a small group of people 00:02:37.495 --> 00:02:39.190 were initially quite receptive. 00:02:39.190 --> 00:02:42.190 It perhaps took some time for a broader group of people 00:02:43.090 --> 00:02:45.912 to come around to seeing the LATE framework 00:02:45.912 --> 00:02:47.620 as a valuable way to look at the world. 00:02:47.620 --> 00:02:49.331 I guess, in over the course of that, 00:02:50.100 --> 00:02:52.128 were there periods where you thought 00:02:52.128 --> 00:02:54.450 maybe the people saying this wasn't a useful way 00:02:54.450 --> 00:02:55.751 to look at the world were right? 00:02:55.751 --> 00:02:58.360 Did you get discouraged? How did you think about? 00:02:58.360 --> 00:02:59.721 - I don't think I was discouraged, 00:02:59.721 --> 00:03:01.119 but the people who were saying that 00:03:01.119 --> 00:03:06.117 were smart people, well-informed econometricians, 00:03:06.117 --> 00:03:07.800 sophisticated readers, 00:03:08.900 --> 00:03:11.324 and I think the substance of the comment 00:03:11.324 --> 00:03:14.297 was this is not what econometrics is about. 00:03:14.297 --> 00:03:20.572 Econometrics being transmitted at that time was about structure. 00:03:21.300 --> 00:03:24.490 There was this idea that there's structure in the economy, 00:03:25.100 --> 00:03:27.200 and it's our job to discover it, 00:03:27.200 --> 00:03:30.952 and what makes its structure is it's essentially invariant. 00:03:32.570 --> 00:03:34.900 And so we're saying, in the LATE theorem, 00:03:34.900 --> 00:03:37.699 that every instrument produces its own causal effect, 00:03:37.699 --> 00:03:41.386 which is in contradiction to that to some extent. 00:03:41.386 --> 00:03:43.640 And so that was where the tension was. 00:03:43.640 --> 00:03:45.551 People didn't want to give up that idea. 00:03:46.300 --> 00:03:50.369 - Yeah, I remember once people started 00:03:51.200 --> 00:03:55.664 arguing more vocally against that -- 00:03:56.900 --> 00:03:59.483 that never really bothered me that much. 00:03:59.483 --> 00:04:03.051 It seemed clear that we had a result there, 00:04:03.051 --> 00:04:05.878 and it became somewhat controversial, 00:04:05.878 --> 00:04:08.395 but controversial in a good way. 00:04:08.620 --> 00:04:10.190 It was clear that people felt 00:04:10.820 --> 00:04:13.835 they had to come out against it because -- 00:04:13.970 --> 00:04:15.649 - Well, I think we think it's good now. 00:04:17.426 --> 00:04:19.238 We might not have loved it at the time. 00:04:20.168 --> 00:04:23.080 - I remember being somewhat more upset -- 00:04:23.080 --> 00:04:24.780 there was some dinner where someone said, 00:04:24.780 --> 00:04:27.455 "No, no, no, that paper with Josh -- 00:04:28.855 --> 00:04:30.749 that was doing a disservice to the profession." 00:04:32.050 --> 00:04:33.850 - We definitely had reactions like that. 00:04:35.410 --> 00:04:38.200 - At some level, that may be indicative of the culture 00:04:38.400 --> 00:04:40.000 in general in economics at the time. 00:04:41.400 --> 00:04:44.097 I thought back later, what if that happened now? 00:04:44.600 --> 00:04:47.682 If I was a senior person sitting in that conversation, 00:04:48.200 --> 00:04:51.952 I would call that out because it really was not appropriate. 00:04:53.000 --> 00:04:54.200 - [Josh] It wasn't so bad. 00:04:54.600 --> 00:04:56.262 I think the criticism is... 00:04:57.700 --> 00:04:59.298 It wasn't completely misguided. 00:05:00.070 --> 00:05:01.351 It was maybe wrong. 00:05:01.800 --> 00:05:04.485 - No, no, but you can say that paper is wrong, 00:05:05.280 --> 00:05:06.440 but it's saying that 00:05:06.440 --> 00:05:08.128 it's a disservice to the profession -- 00:05:08.128 --> 00:05:10.300 - that's not really... - [Isaiah] It's a bit personal. 00:05:10.300 --> 00:05:12.646 - Yes, and doing that not to me 00:05:12.646 --> 00:05:14.442 but in front of my senior colleagues. 00:05:15.191 --> 00:05:17.369 - But nobody was saying the result was wrong, 00:05:17.369 --> 00:05:18.700 and I remember also, 00:05:18.700 --> 00:05:21.579 some of the comments were thought-provoking. 00:05:21.579 --> 00:05:23.059 So we had some negative reviews, 00:05:23.059 --> 00:05:25.861 I think, on the average causal response paper. 00:05:26.500 --> 00:05:30.361 Somebody said, "These compliers -- you can't figure out who they are." 00:05:31.967 --> 00:05:33.891 It's one thing to say you're estimating 00:05:33.891 --> 00:05:35.678 the effect of treatment on the treated 00:05:35.678 --> 00:05:36.840 or something like that. 00:05:36.840 --> 00:05:38.400 You can tell me who's treated. 00:05:38.837 --> 00:05:42.289 People in the CPS, you can't tell me who's a complier. 00:05:42.929 --> 00:05:44.679 So that was a legitimate challenge. 00:05:44.679 --> 00:05:47.800 - That's certainly fair, and I can see why 00:05:49.880 --> 00:05:53.502 that part made people a little uneasy and uncomfortable. 00:05:54.300 --> 00:05:56.400 But at the same time, 00:05:56.900 --> 00:06:00.244 because it showed that you couldn't really go beyond that, 00:06:00.800 --> 00:06:03.775 it was a very useful thing to realize. 00:06:04.630 --> 00:06:08.831 I remember on the day we got to the key result 00:06:09.238 --> 00:06:13.113 that I was thinking, "Wow, this is as good as it gets. 00:06:14.221 --> 00:06:16.978 Here we actually have an insight, but it clearly..." 00:06:17.500 --> 00:06:19.250 - And we had to sell it at some point. 00:06:19.480 --> 00:06:21.261 For quite a few years, we had to sell it, 00:06:23.480 --> 00:06:24.892 and it's proven to be quite useful. 00:06:25.500 --> 00:06:28.761 I don't think we understood that it would be so useful at the time. 00:06:28.761 --> 00:06:29.871 - No. 00:06:30.170 --> 00:06:34.600 I did feel early on this was a substantial insight. 00:06:34.600 --> 00:06:36.440 - [Josh] Yeah, we'd done something. 00:06:36.440 --> 00:06:40.041 - But I did not think goals were there. 00:06:40.700 --> 00:06:42.600 - I don't think we were aiming for the Nobel. 00:06:42.600 --> 00:06:43.730 [laughter] 00:06:43.730 --> 00:06:46.243 We were very happy to get that note in Econometrica. 00:06:46.859 --> 00:06:48.829 ♪ [music] ♪ 00:06:49.770 --> 00:06:51.560 - [Isaiah] Are there factors or are ways of approaching problems 00:06:51.560 --> 00:06:54.186 that lead people to be better at recognizing the good stuff 00:06:54.186 --> 00:06:56.600 and taking the time to do it as opposed to dismissing it? 00:06:56.600 --> 00:06:57.830 - [Josh] Sometimes I think it's helpful. 00:06:57.830 --> 00:06:59.478 If you're trying to convince somebody 00:06:59.478 --> 00:07:01.247 that you have something useful to say 00:07:01.900 --> 00:07:04.176 and maybe they don't speak your language, 00:07:04.894 --> 00:07:06.761 you might need to learn their language. 00:07:06.761 --> 00:07:07.910 - Yes, yes, exactly. 00:07:07.910 --> 00:07:11.736 - That's what we did with Don, we figured out how to -- 00:07:11.736 --> 00:07:14.052 I remember we had a very hard time 00:07:14.052 --> 00:07:16.058 explaining the exclusion restriction to Don, 00:07:17.430 --> 00:07:18.993 maybe rightfully so. 00:07:19.804 --> 00:07:21.948 I think Guido and I eventually figured out 00:07:21.948 --> 00:07:24.420 that it wasn't formulated very clearly, 00:07:25.400 --> 00:07:27.450 and we came up with a way to do that 00:07:27.450 --> 00:07:29.316 in the potential outcomes framework 00:07:29.316 --> 00:07:32.218 that I think worked for the three of us. 00:07:32.218 --> 00:07:33.419 - [Guido] Yeah. 00:07:33.419 --> 00:07:35.454 Well, it worked for the bigger literature, 00:07:35.454 --> 00:07:37.639 but I think what you're saying there is exactly right. 00:07:37.639 --> 00:07:40.860 You need to figure out how not just say, 00:07:40.860 --> 00:07:43.894 "Okay, I've got this language, and this works great, 00:07:43.894 --> 00:07:45.900 and I've got to convince someone else to use the language." 00:07:45.900 --> 00:07:48.188 You could first figure out what language they're using, 00:07:48.680 --> 00:07:51.028 and then, only then, can you try to say, 00:07:51.028 --> 00:07:53.140 "Well, but here you're thinking of it this way." 00:07:53.140 --> 00:07:56.880 But that's actually a pretty hard thing to do. 00:07:56.880 --> 00:07:59.098 You get someone from a different discipline, 00:07:59.098 --> 00:08:02.405 convincing them, two junior faculty in a different department 00:08:02.405 --> 00:08:04.366 actually have something to say to you -- 00:08:04.596 --> 00:08:06.516 that takes a fair amount of effort. 00:08:07.500 --> 00:08:09.782 - Yeah, I wrote Don a number of times, 00:08:10.420 --> 00:08:11.868 in fairly long letters. 00:08:11.868 --> 00:08:13.805 I remember thinking this is worth doing, 00:08:14.600 --> 00:08:16.006 that if I could convince Don, 00:08:16.780 --> 00:08:19.444 that would validate the framework to some extent. 00:08:20.300 --> 00:08:22.522 - I think both you and Don 00:08:22.522 --> 00:08:25.000 were a little bit more confident that you were right. 00:08:25.000 --> 00:08:26.438 - Well, we used to argue a lot, 00:08:26.438 --> 00:08:28.320 and you would sometimes referee those. 00:08:28.320 --> 00:08:29.500 [laughter] 00:08:29.800 --> 00:08:30.800 That was fun. 00:08:32.760 --> 00:08:34.125 It wasn't hurtful. 00:08:35.200 --> 00:08:37.492 - I remember it getting a little testy once. 00:08:37.935 --> 00:08:39.606 We had lunch in The Faculty Club, 00:08:40.600 --> 00:08:44.077 and we were talking about the draft lottery paper. 00:08:44.930 --> 00:08:47.430 We were talking about "never takes" 00:08:47.430 --> 00:08:49.761 as people wouldn't serve in the military 00:08:49.761 --> 00:08:53.500 irrespective of whether they were getting drafted, 00:08:54.500 --> 00:08:56.936 and you or Don said something 00:08:56.936 --> 00:08:58.800 about shooting yourself in the foot... 00:08:58.800 --> 00:08:59.800 [laughter] 00:08:59.800 --> 00:09:01.530 ...as a way of getting out of the military 00:09:01.530 --> 00:09:03.230 and that maybe the exclusion restriction 00:09:03.230 --> 00:09:05.743 for "never takes" wasn't working. 00:09:06.300 --> 00:09:08.520 And then the other one was going, 00:09:08.520 --> 00:09:09.791 "Well, yes, you could do that, 00:09:09.791 --> 00:09:12.008 but why would you want to shoot yourself in the foot?" 00:09:12.008 --> 00:09:13.225 [laughter] 00:09:13.225 --> 00:09:15.400 It got a little there... 00:09:15.400 --> 00:09:17.860 - I usually go for moving to Canada for my example, 00:09:18.690 --> 00:09:20.096 when I'm teaching that. 00:09:20.096 --> 00:09:21.365 [laughter] 00:09:22.030 --> 00:09:23.375 - But things are tricky. 00:09:24.860 --> 00:09:26.595 I get students coming from Computer Science, 00:09:26.595 --> 00:09:29.943 and they want to do things on causal inference, 00:09:30.190 --> 00:09:33.460 and it takes a huge amount of effort to figure out 00:09:33.460 --> 00:09:35.230 how they're actually thinking about a problem 00:09:35.230 --> 00:09:37.000 and whether there's something there. 00:09:37.000 --> 00:09:38.310 And so, now, over the years, 00:09:38.310 --> 00:09:39.720 I've got a little more appreciation 00:09:39.720 --> 00:09:41.958 for the fact that Don was actually willing to -- 00:09:42.630 --> 00:09:46.000 It took him a while, but he did engage first with Josh 00:09:46.400 --> 00:09:47.500 and then with both of us, 00:09:48.671 --> 00:09:50.245 rather than dismissing and saying, 00:09:50.245 --> 00:09:53.348 "Okay, well, I can't figure out what these guys are doing, 00:09:53.348 --> 00:09:56.435 and it's probably just not really that interesting." 00:09:57.200 --> 00:09:59.736 - Everybody always wants to figure out quickly. 00:10:00.196 --> 00:10:01.376 You want to save time, 00:10:01.376 --> 00:10:03.410 and you want to save your brain cells 00:10:03.410 --> 00:10:04.583 for other things. 00:10:05.000 --> 00:10:07.000 The fastest route to that is to figure out 00:10:07.000 --> 00:10:08.460 why you should dismiss something. 00:10:08.460 --> 00:10:09.560 - Yes. 00:10:09.560 --> 00:10:11.100 - I don't need to spend time on this. 00:10:11.100 --> 00:10:12.498 ♪ [music] ♪ 00:10:12.498 --> 00:10:15.143 - [Narrator] If you'd like to watch more Nobel Conversations, 00:10:15.143 --> 00:10:16.207 click here. 00:10:16.207 --> 00:10:18.409 Or if you'd like to learn more about econometrics, 00:10:18.640 --> 00:10:21.240 check out Josh's Mastering Econometrics series. 00:10:21.800 --> 00:10:24.540 If you'd like to learn more about Guido, Josh, and Isaiah, 00:10:24.860 --> 00:10:26.502 check out the links in the description. 00:10:26.992 --> 00:10:28.697 ♪ [music] ♪