BREAD-IGC virtual PhD-level course 2026 | Lecture 3 Core Political Economy Models — Transcript
Full transcript
- 0:34All right, welcome everyone uh back to
- 0:37the Brad IGC
- 0:40Bred uh PhD level course on political
- 0:43economy. We are here for our third
- 0:45lecture. We're very grateful to have Pat
- 0:47Patrick Francois with us. He's a
- 0:50professor at the University of British
- 0:52Columbia and teaches in the Vancouver
- 0:54School of Economics.
- 0:56And before I pass over to him, I just
- 0:58want to go over our kind of standard
- 1:01housekeeping items. Um, I will put this
- 1:03in the chat as well, but all the reading
- 1:07lists, slides, and past recordings are
- 1:11available on our website. I'll put that
- 1:13link in. And so, if you have questions
- 1:16around you missed a week or or the
- 1:19reading list for next week, just check
- 1:22um that location. The second thing is
- 1:26for attendance
- 1:28that is captured automatically by Zoom.
- 1:30So you don't need to send in any
- 1:32personal note or email saying that that
- 1:35you were here. And there is a a bar of
- 1:4010 uh 10 kind of lectures attended for
- 1:44the cert certification
- 1:47um at the end of the course. this being
- 1:50the third, the this will if you if
- 1:53you're just joining this week and you
- 1:55attend the next uh this one and the next
- 1:58nine, then you'll still be able to get
- 1:59that that certificate.
- 2:01Um now, if anyone would like to kind of
- 2:04be a live participant here and have
- 2:06their video on uh to be in kind of the
- 2:10virtual classroom, please raise your
- 2:11hand now and I'll randomly select 15 or
- 2:1320 of you. uh please still keep your mic
- 2:17muted but your video on and then during
- 2:19the Q&A session you'll be able to
- 2:21interact and ask um questions. For
- 2:23others that have questions just put them
- 2:25into the Q&A box and we'll try to answer
- 2:28those throughout.
- 2:30Okay, I think that's everything from me.
- 2:32So I'll pass it over to Patrick to kind
- 2:35of go over um everything that we need to
- 2:38know about core political economy
- 2:39models.
- 2:42Okay, thanks [clears throat] Caleb and
- 2:45thanks to IGC and Brad and CPR for
- 2:48having me for this uh this lecture.
- 2:50Okay, so uh yeah, I'm not going to teach
- 2:53you everything you need to know about
- 2:54political economy models. There's a lot
- 2:56more that I'm that I'm going to miss
- 2:57that I'm going to cover, I'd say. Um
- 3:02uh okay, so I can't see the top of that,
- 3:05but I guess you can. So yeah, there we
- 3:07go. So, um,
- 3:10what's this, uh, lecture going to be
- 3:12about? It's going to be back to thinking
- 3:15about, uh,
- 3:19what we do with models. Okay? So, I'm
- 3:21not going to survey political economy
- 3:23models. I I want you to take away from
- 3:26this lecture answers to the following
- 3:29questions. what models are for, how
- 3:33modeling actually begins, applied
- 3:34modeling, how a canonical model becomes
- 3:36useful for you, and I'm going to talk
- 3:38about a few of the canonical models at a
- 3:40very high level, how model adds value to
- 3:43data, and where you must exercise
- 3:45judgment.
- 3:47Okay? So my aim is for you to see econom
- 3:50data in a model first way. Okay? So in
- 3:54order to do that, I want you to think
- 3:56back to undergraduate economics. Okay.
- 3:59So, when you first started taking
- 4:02economics and I think you probably all
- 4:04did what I did, you start with thinking
- 4:07about markets and
- 4:10the actual observables you have in
- 4:12markets are essentially quantities and
- 4:14prices. That's what we see in markets.
- 4:17Yet, that's not really what we deal
- 4:20with. What we first do is we make up
- 4:22this abstraction
- 4:24which is the idea of supply and demand
- 4:26which are fictions. right? We we make up
- 4:29a supply curve, a demand curve. We think
- 4:31about them when we go a little bit
- 4:33further. We think about like the
- 4:34underpinnings of that things like
- 4:36consumer choice and the behavior of the
- 4:38firm. Um and then we kind of go a little
- 4:40bit further and we think about
- 4:41monopolies and things like
- 4:42externalities.
- 4:44So
- 4:46when we're thinking about the actual
- 4:48observables, quantities and prices,
- 4:50we're not basically doing this a
- 4:52theoretical thing, which is to say,
- 4:54well, you know, a natural question would
- 4:55be to ask how are these things
- 4:56correlated? How do quantities and prices
- 4:59move together? And that's not a sensible
- 5:02question. That's actually a question
- 5:05that if you did that, you'd find all
- 5:06sorts of weird correlations between
- 5:08quantities and prices depending on which
- 5:10curve was moving in the background,
- 5:11supply or demand. So our our way of
- 5:14thinking about it is really structured
- 5:16by the fiction that really drives our
- 5:19empirical approach to them.
- 5:21And I want to argue to you that this is
- 5:24how we as economists think implicitly
- 5:26for the rest of our careers. We're
- 5:28really conditioned by that way of
- 5:30thinking and it's a good thing and
- 5:34we should do that in the political
- 5:37economy realm as well. Okay. So what do
- 5:39these simple models actually teach us?
- 5:42They teach us the same things that we
- 5:44learn essentially in the supply and
- 5:46demand world. So in the in the supply
- 5:49and demand mode just remind you what are
- 5:50those things in a market we ask what
- 5:51shifted demand what shifted supply and
- 5:53remember these are fictions right
- 5:54they're not the real things we observe
- 5:56what shifted those things which margin
- 5:58moved what's the equilibrium response
- 6:01what happens if we were to do something
- 6:02like intervene so that the model becomes
- 6:06so ingrained in our thinking about this
- 6:10context that it actually becomes the
- 6:11language of our conceptions in our mind
- 6:16deeply
- 6:18So I'm going to argue the political
- 6:20economy thinking about political economy
- 6:21as grad students or as advanced
- 6:23economists needs the same kind of
- 6:25language. So um a small number of
- 6:28strategic problems happen again and
- 6:30again in political economy contexts.
- 6:33Okay. So just to list them I mean this
- 6:35is my kind of uh thinking about it and
- 6:38I'm sure there are others that uh I
- 6:40don't think about too much but here are
- 6:41the ones that are important for me.
- 6:42Politicians competing for voters. Voters
- 6:45disciplining politicians. Citizens
- 6:47deciding whether to become politicians
- 6:49themselves. Politicians bargaining over
- 6:52how to divide things up. Usually the big
- 6:54thing is power. Groups expending
- 6:57resources to actually control political
- 6:59office. The credibility of promises made
- 7:03by politicians. Citizens trying to
- 7:06coordinate punishments and to discipline
- 7:08politicians and information asymmetries
- 7:12that arise between the informed actors.
- 7:14usually the political agents and and and
- 7:17the principles who are the voters.
- 7:19So I'm going to argue that these are the
- 7:21political economy equivalents of supply
- 7:22and demand.
- 7:25Okay. So we can I I I put these readings
- 7:30on the reading list. They're by no means
- 7:32essential, but these are the ones that
- 7:34for me are the canonical models that
- 7:38provide a a sort of a conceptual way of
- 7:41thinking about these problems. So the
- 7:43Dian models for politicians competing
- 7:46for voters. The fair John and Fieran
- 7:48paper um in in the issue of voters
- 7:52disciplining politicians citizens entry
- 7:55into polit political office is the
- 7:57Osborne Slovinsky and Basian co-papers
- 8:00politics and bargaining overpowered
- 8:01Baron Fjon and on and on. So here
- 8:04they're listed. I'm going to list them
- 8:05again later. I'm not going to go through
- 8:07any of these models in any detail.
- 8:10I think it's not that useful to do it in
- 8:12a short period of time, but just so you
- 8:14have them, these are the ones that I go
- 8:16to first. They come into my mind when I
- 8:18think about these particular situations.
- 8:21Okay. So, what's the point of them? The
- 8:24point of reading these, I think, is
- 8:25great. They're great papers. They're
- 8:26famous papers for the most part, but you
- 8:29don't need to remember anything about
- 8:30them. They're useful. Why? because they
- 8:35have a sort of a strategic structure and
- 8:37architecture
- 8:39which when you learn to recognize them
- 8:42you can
- 8:44see and think about how to apply them in
- 8:46empirical settings. So once you
- 8:47recognize them you see this that this
- 8:50structure sort of pops up in a lot of
- 8:51empirical contexts and it can motivate
- 8:53your your way of thinking about the
- 8:56data.
- 8:58So applied modeling usually does start
- 9:00with data and this is a sense in which
- 9:02as graduate students you will usually
- 9:05come at a problem with data first and
- 9:08that's a good thing. So I think this is
- 9:10very different than and what I want to
- 9:12talk about today is very different than
- 9:13being a theorist. You know I'm not a
- 9:15theorist. I'm I'm an applied theorist. I
- 9:17I look at data. I usually work with
- 9:21empirical people or I do some rud
- 9:23rudimentary empirical work myself and
- 9:25then I think about how to structure it
- 9:27using models.
- 9:28Okay. So, so it starts with data and I
- 9:30think this is a great this is where we
- 9:32should start. We should be disciplined
- 9:33by data and suppose that you have built
- 9:35a data set from something, right? So, it
- 9:37could be a a an RCT could be you have
- 9:40access to administrative data. You've
- 9:42come to the archives and you've created
- 9:44one surveys, census, web scraping, which
- 9:47is incredibly common and cheap and
- 9:49relatively easy to do now or just obser
- 9:52ordinary observational data.
- 9:54Okay? So you do that work, you do it
- 9:57carefully and you might even find
- 9:59something interesting. So you find some
- 10:00interesting correlations or even some
- 10:02interesting causal relations.
- 10:04So so what often happens is the data is
- 10:07telling you something, right? So
- 10:08something like this. X goes up and Y
- 10:10then goes up. Okay? And maybe you've
- 10:13established it well. You've even got a a
- 10:14clear causal relationship. It's X going
- 10:16up that makes Y go up. Okay? So you can
- 10:20write a paper just showing that. And for
- 10:22some data, for some variables, that's
- 10:26actually super important just to
- 10:28establish a causal relation like that.
- 10:30And usually that's going to be important
- 10:33as a standalone fact on its own. Once
- 10:36theory and once the profession is
- 10:38decided, we need to know that
- 10:39relationship. So once that's already
- 10:41decided, then just establishing it
- 10:44empirically can itself be an important
- 10:46contribution. But that's not usually the
- 10:49case for students doing PhDs. They don't
- 10:52usually happen upon the key empirical
- 10:56finding that's just going to resolve a
- 10:57bunch of theoretical or or open
- 11:00conjectures in in economics. That's not
- 11:02usually what happens. What usually
- 11:03happens is you just found a correlation
- 11:04in some data. Now, when it becomes when
- 11:08you can elevate that to something that's
- 11:10a more significant contribution is when
- 11:12you can answer a different question,
- 11:14which is the why question. And that's
- 11:16the modeling question. Why is this
- 11:18happening?
- 11:20So the implied modeling sequence is
- 11:22inserting the modeling thinking into
- 11:26that data collection process. So this is
- 11:29where it fits. You have data, you
- 11:32establish an empirical fact like X goes
- 11:35up then Y follows. Then you think about
- 11:37a mechanism and a mechanism is just a
- 11:40story, a narrative, a parable, whatever
- 11:43you want to put it, but it's just what's
- 11:45going on here. Then you formalize it,
- 11:47okay, with a model. And that's because
- 11:50means a few reasons why we want to
- 11:51formalize it. We'll get into that in in
- 11:53a little bit, but in a nutshell, it's
- 11:55because telling the story often doesn't
- 11:57do the full idea justice. It's hard to
- 12:00tell whether it all hangs together. And
- 12:02a model helps you know whether it hangs
- 12:04together. But it does much more. One of
- 12:05the things that actually can and should
- 12:08do, I'd argue, is provide new
- 12:10predictions. Then it tells you where to
- 12:12go and get new evidence. Often there's a
- 12:14back and forth between data, theory, and
- 12:17data. So the model sits inside, it's
- 12:19embedded in this what I call empirical
- 12:21research process.
- 12:23So step one is often very simple and
- 12:25modest. And what is that step one?
- 12:28First, it has to explain the thing you
- 12:29found. That's the point of building the
- 12:31model, right? If the data says A goes
- 12:34up, then B goes up and C equals 1
- 12:37implies B goes down, then your mechanism
- 12:40should be able to generate both of those
- 12:42things. So you have to think about a
- 12:43story. If it can't do that, if the story
- 12:45can't explain the basic observations you
- 12:48have, it's failed at step one. So that's
- 12:50where you exist in the first instance.
- 12:53You have to try to use the model, your
- 12:55thinking, your story to explain what
- 12:57you're observing. Okay? But the problem
- 13:00is it's not a problem, but the fact is
- 13:03uh that's pretty easy to do in a lot of
- 13:05context, right? Rationalization is
- 13:07cheap. And that's just why because we're
- 13:10good at telling stories. Like this is
- 13:11just part of what humans do. We're great
- 13:14at it, right? So we can tell any sort of
- 13:16BS story. BS meaning not true and with
- 13:19enough assumptions you can almost
- 13:21rationalize any fact. So some of these
- 13:23stories are not very interesting but
- 13:25they may be true. So reducing so just
- 13:28making the story fit the correlation
- 13:30that's the point of it but that's
- 13:32obviously not sufficient. Okay. So then
- 13:34the question is what what would make it
- 13:36sufficient? And this what would make it
- 13:38sufficient is when the model's starting
- 13:40to provide some discipline beyond the
- 13:42initial story that you came up with. So
- 13:44what I mean a m a useful model should do
- 13:46this. It should tell you some of these
- 13:48things. So one of them is it should tell
- 13:50you when the result holds. So x going up
- 13:53implies y going up. That's the data. But
- 13:56maybe the model tells you and this is
- 13:59embedded into your structure is that
- 14:03well that's only if some parameter alpha
- 14:05is greater than alpha bar. Why is that
- 14:07useful? Well, firstly, it's it's may
- 14:10just be a a consequence of something
- 14:13that's totally arbitrary like the
- 14:14functional form assumption. If it's
- 14:16that, then it's not useful. But if it's
- 14:18profoundly part of the story, that in a
- 14:20sense that you can't write down a
- 14:22functional form that wouldn't make it
- 14:23true. It actually depends on this
- 14:25parameter alpha being high enough, then
- 14:28that's giving you a new empirical
- 14:31question, right? It's saying where in
- 14:33the data should this hold? Is there a is
- 14:35there something that corresponds to
- 14:36alpha in the data? If it's doing that
- 14:38then it's already giving us more than
- 14:40just a rationalization.
- 14:42It should generate some sort of
- 14:43heterogeneity. Right? So suppose like I
- 14:46said y goes x goes up y goes up
- 14:51then we should also have something else
- 14:54like this that well that depends on zed
- 14:57as well. So if you see an interaction
- 14:59term like that second derivative is also
- 15:02positive. The model says the effect
- 15:03should be stronger where zed is high.
- 15:05Maybe nobody looked at that. Maybe you
- 15:07didn't think about that before the model
- 15:09existed. If that's the case, again, it's
- 15:10a useful model.
- 15:13It should generate some auxiliary
- 15:15predictions. These are auxiliary. But
- 15:16here's some more. The motivating factor
- 15:18is X goes up, Y goes up. Also, the
- 15:19mechanism should also imply if X goes
- 15:21up, maybe W goes down. Often W wasn't
- 15:24even thought of when you were getting
- 15:26the data when you were initing the facts
- 15:28or when you were constructing the model.
- 15:30and and in that case it's it's likely
- 15:32that the prediction is super
- 15:33informative. It's again telling you
- 15:35somewhere else to look empirically. So
- 15:37the model here is a tool and it's a tool
- 15:40because we're not smart enough to do all
- 15:41this abstractly in our head or in or in
- 15:43narrative or in English. Putting it in
- 15:45math allows us to get insights that we
- 15:48couldn't get otherwise.
- 15:51So um let's just take an example of
- 15:54that. So this is all that's all abstract
- 15:56in terms of x's and y's and ws. suppose
- 15:57the motive fact is this that you know
- 15:59coastal constituencies so if you get you
- 16:02know little electorates or little um
- 16:04political contests that are near the
- 16:05coast tend to have more corruption I
- 16:08don't know if this is a fact I'm just
- 16:09making it up so let's just think about a
- 16:11story so one one possible mechanism is
- 16:13there's reduced spatial competition
- 16:15right so when constituents or businesses
- 16:18uh have fewer substitutes nearby because
- 16:20one side is bounded by the sea there's
- 16:22less discipline on political bad actors
- 16:25there's there's less latitude but less
- 16:26places fewer places to go. So then the
- 16:29model should also predict what that
- 16:30lakefront constituencies should have
- 16:33more corruption because they have the
- 16:34same issue. So lakes were never part of
- 16:37the facts used to motivate the model
- 16:38that the model was about data which was
- 16:41about the coast versus the inland.
- 16:45This story would tell you look if that's
- 16:47the right thing then it should be true
- 16:48in lakes too and in big lakes.
- 16:52So that comes from the mechanism and
- 16:54it's not just mechanically extending the
- 16:56correlation. You could just mechanically
- 16:57extend it by saying, "Well, it's just
- 16:59water and there's water there." That's
- 17:00not it. It's about this spatial
- 17:02component.
- 17:05Okay? So, sometimes the models are going
- 17:07to actually tell you what data to
- 17:08collect. So, I can point to another
- 17:10variable, another question, something
- 17:12about beliefs. You should ask people
- 17:14about their beliefs, information,
- 17:15another treatment. So, this arrow from
- 17:18data to thinking about the model, then
- 17:20to new data, that's great if that
- 17:23happens. And sometimes as I said earlier
- 17:28actually usually lots of mechanisms are
- 17:30going to fit the same fact. So you know
- 17:32you might have model A B and C that can
- 17:34all generate when X goes up Y goes up.
- 17:37That's normal.
- 17:40When these models become valuable is
- 17:42when they start generating differences.
- 17:44So if they're exactly equivalent then
- 17:47we've got no way of telling between
- 17:49them. But that's rarely the case. Right?
- 17:52So when they diverge then they start
- 17:56providing possibilities for
- 17:58distinguishing between them.
- 18:01So
- 18:02the model then becomes a machine that
- 18:06you can use to design your data
- 18:07collection moving forward. So what
- 18:10comparative statics differ across the
- 18:11models? Which subgroups differ? What
- 18:14treatments would distinguish the
- 18:16mechanisms? What observables would move
- 18:19them in different directions? and what
- 18:21new data should you collect? So theory
- 18:24can tell the empiricists what to do
- 18:25next. So we should all as empiricists,
- 18:28we should all also be theorists in this
- 18:30sense. So it's particularly useful if
- 18:32done prior to going to the field or
- 18:35after piloting after you've been to the
- 18:36field and got a sense of what's going
- 18:38on. You might have some prior about the
- 18:40variables you should think about. When
- 18:42you see the piloting, when you go to the
- 18:45field, when you speak to people, you're
- 18:46like, you know, these are not the big
- 18:47moving parts. I should think about
- 18:49something else. I have a mechanism in
- 18:50mind. It tells me other things that I
- 18:53should ask.
- 18:55So I'm going to provide an illustration.
- 18:57I think this is a great model. I I put
- 19:00it as an a reading to do. Uh it's a it's
- 19:03a paper from Gerard Padre Miguel in
- 19:06Review of Economic Studies and it
- 19:08basically asks the question and it's a
- 19:10pure theoretical paper. Okay. Why do
- 19:12citizens continue to support leaders who
- 19:15are basically stealing from them or
- 19:18governing terribly? So
- 19:21usually and he starts from this position
- 19:23that this is got something to do with
- 19:25identity. People tend to support people
- 19:26who are from the same identity group. So
- 19:28it happens in in societies that are
- 19:30polarized or clustered around identity
- 19:33markers like for instance tribal
- 19:35markers. So he notes that a tempting
- 19:38explanation I don't think he actually
- 19:40notes this but I think a tempting
- 19:41explanation is just say look we've got a
- 19:43taste for supporting somebody from our
- 19:45own group. We just have an inherent
- 19:46tendency to want to support people vote
- 19:49for people who are like us
- 19:50linguistically culturally physically you
- 19:54could just say this is like a
- 19:56psychological tendency. Okay. So he
- 20:00takes I think a much more deep economic
- 20:03approach. She says look this can emerge
- 20:04from an interaction that we don't have
- 20:06to posit that as a feature of our
- 20:09preferences. This can be an equilibrium
- 20:11outcome.
- 20:13Okay. So here's the core mechanism. So
- 20:15if you've read the paper you'll be
- 20:16familiar with the notation here. This is
- 20:20sort of a a slightly bastardized version
- 20:21of his notation. But I think the
- 20:24interesting thing is that um that his
- 20:26his uh his his his
- 20:29theoretical approach is you know a a
- 20:32beautiful elegant way of generating the
- 20:35story as an emergence rather than a
- 20:37direct assumption. Okay. So suppose the
- 20:39following is true. He he makes his
- 20:41assumption. Suppose if you keep the
- 20:43incumbent the probability that you're
- 20:44going to hold on to power is greater. So
- 20:47he calls this gamma overbar and I'm
- 20:50going to call it for a for group A.
- 20:52That's the probability you'll stay in
- 20:54power if you keep your incumbent in
- 20:55power. If you remove your incumbent,
- 20:57that probability is lower. Some gamma
- 20:59underbar a and suppose I value holding
- 21:02power. So that means the value to me as
- 21:05an a person if I have an a leader is
- 21:07bigger than the value if I have a b
- 21:09leader. Okay.
- 21:12So he notes and he generates this as an
- 21:15equilibrium object that supporters may
- 21:19accept a loss as large as this amount.
- 21:22Okay. And this is a kind of a political
- 21:24slack. And the story is very simple. If
- 21:28I were [snorts] to remove my current
- 21:30politician then I will have suffer this
- 21:33decline in the probability of holding
- 21:36power. How much do I value holding
- 21:38power? This much. So that's the actual
- 21:42amount that I fear losing
- 21:45and delta is a discount rate.
- 21:49This is a type of a rent that the
- 21:52politician
- 21:53can exploit. They can do things up to
- 21:56this. They can steal up to this. They
- 21:58can be slack up to this. It's a
- 22:00political rent. That e kleptocratic rent
- 22:03that he calls it. So the more I fear the
- 22:05other group taking power, the more badly
- 22:07my own leader can treat me. Why is this?
- 22:09Well, the worse it would be for me if
- 22:11the other group takes power, the bigger
- 22:13this rent is. So, this is his mechanism
- 22:17for explaining why people will be in an
- 22:21equilibrium where they continually
- 22:22support leaders who are venal corrupt
- 22:27mal in whatever way. Okay.
- 22:31So, it's a nice model and if it were
- 22:33just a model and it is just a model in
- 22:35his version, it's nice enough that it
- 22:37makes this complicated dynamic problem
- 22:39very simple. You can see the moving
- 22:41parts and that's why it was published,
- 22:43you know, 20 years ago in the review of
- 22:44economic studies. It's a great paper.
- 22:49Okay, so this is just kind of the
- 22:51technique of it, which I think is nice
- 22:53too. It makes the problem simple, but I
- 22:54won't go into that too much. Now I want
- 22:56to tell you what my co-author and I did
- 23:00when we saw a an empirical fact in in
- 23:04Maharashtra. So we were collecting data
- 23:05there and we found this very unusual
- 23:08empirical pattern. We found that when a
- 23:11political office was reserved for a
- 23:13member of a particular cast and here it
- 23:16was OBC but just think about a cast
- 23:18that's not traditionally a powerful cast
- 23:21then mil village governance actually
- 23:24improved and the effect was concentrated
- 23:27uh in these OBC groups that were large
- 23:29but not super dominant and we found that
- 23:32the observed characteristics of the
- 23:34leader did little to account for the
- 23:36pattern. So it didn't seem like it was a
- 23:38improving the quality of people's
- 23:40standing per se. Okay. So normally we
- 23:43might have expected the following. So if
- 23:45you restrict who can stand for office,
- 23:47that means you're implying there's less
- 23:49competition and that means you're going
- 23:51to get worse governance.
- 23:53Okay, so that's what we would usually
- 23:55think, but we found that governance was
- 23:57improving. So what we realized was that
- 23:59the politics of fear model, that model
- 24:01that I just gave you, was able to affect
- 24:05a margin that could be explaining this
- 24:07data. Okay? So we cannibalized that
- 24:09model.
- 24:11Okay. The original model contained a lot
- 24:12of structure that just wasn't important
- 24:14in the Maharashtran village setting.
- 24:16Okay? There was activity specific t
- 24:18taxation. There was a particular form of
- 24:20specialization. These things weren't
- 24:22that relevant. And the reason is because
- 24:24the capacity to tax in that context was
- 24:26very low. And this specialization story
- 24:28just wasn't relevant for these different
- 24:30OBC groups.
- 24:33So what we did keep was what was
- 24:34essential and that is that basic
- 24:36equation that I showed you. The value of
- 24:38group control plus leader specific
- 24:40advantage and retaining it was
- 24:41generating the rent and what
- 24:44reservations political reservations were
- 24:46doing was essentially affecting the
- 24:49entry margin. They they affected who
- 24:51could compete for leadership.
- 24:54And when a reservation was given to a
- 24:56group, it meant that the competition had
- 24:58to come entirely from within because
- 25:00that group was guaranteed to win. Okay?
- 25:04So that original politics of fear model
- 25:07didn't have a process for replacing
- 25:09incumbents.
- 25:11But political reservation works
- 25:13precisely by changing that replacement
- 25:15possibility. Okay. So we built an
- 25:18extension which modeled the challenger
- 25:20entry and the governance offer that a
- 25:22challenge makes. So what often happens
- 25:24and this is what happened in this
- 25:25context that modeling in a particular
- 25:28context requires taking that off the
- 25:30path off off off the shelf model and
- 25:34making something which was relatively
- 25:38minor in that model here it was an off
- 25:40path behavior into the core of the
- 25:42model. So that's the case in a lot of
- 25:45those core models. They're focused on a
- 25:47generic economic context, but when you
- 25:49get a particular empirical setting, it
- 25:51tells you what you need to focus your
- 25:53model on. So we built down this
- 25:55extension and here we had two
- 25:58politically coherent groups or juties
- 26:00and the leader would obtain office
- 26:02rents. Citizens would value holding
- 26:04office and the leader would choose how
- 26:06much effort to put in. Okay. So I won't
- 26:09go into the details of that but
- 26:11essentially we took things that were not
- 26:13in that model and added them in but kept
- 26:15that core structure. So this was simpler
- 26:17than the original tax and patronage
- 26:19model of his but richer in the dimension
- 26:21where where the data was rich. Okay. So
- 26:24so what I want to tell you is this led
- 26:28to a set of very different predictions
- 26:31than his original model had. Okay. But
- 26:33it was still using the same idea. So
- 26:36here's what a reservation does in using
- 26:38the thinking of his model. So without a
- 26:41reservation, remember the probability
- 26:43that the group will hold office if they
- 26:46keep their leader is some gamma a
- 26:50uppercase. If they replace him with a
- 26:53challenger, it's gamma a lower case and
- 26:56this is lower. That's the cost of moving
- 26:58against an incumbent who might be
- 27:00terrible. That's the cost. So you have
- 27:02to risk losing control. With a
- 27:04reservation, both of those just go to
- 27:07one. So that difference collapses. Why
- 27:09does it go to one? Because essentially
- 27:13the electoral office says to you, you
- 27:15know, you've won. Your group has one
- 27:17office for sure. It's been reserved for
- 27:18you. That's going to change the law of
- 27:21motion of political power. And that
- 27:23changes everything in that model. So now
- 27:28the disciplining has come from entry
- 27:30from within. Before the disciplining on
- 27:32power was losing to another group, but
- 27:35that created a lot of bad problems for
- 27:38the constituents supporting the leader.
- 27:39Now you could throw out your leader.
- 27:42You're guaranteed to hold power. So the
- 27:45discipline now comes from who's going to
- 27:46want to challenge. What could how how
- 27:49good could they do? What can they
- 27:50promise you? So this changes the
- 27:52equilibrium by changing the off path
- 27:54behavior.
- 27:56So the incumbent's electoral advantage
- 27:58creates an equilibrium rent he consumes
- 27:59as lower governance in the politics of
- 28:02fear model with a reservation that's
- 28:04gone and so has the rent.
- 28:07So the model delivers
- 28:09essentially
- 28:11an empirical prediction which is one
- 28:13that we wanted to generate right that
- 28:17this was the level of governance in an
- 28:20unreserved village. It was whatever the
- 28:22first best was minus some amount. That's
- 28:25the politics of fear in the reservation.
- 28:29That level of governance, the difference
- 28:30between a reserved and an unreserved
- 28:34was positive. A reservation would
- 28:36improve governance. So this was
- 28:38generating the raw empirical fact that
- 28:41we found which of of course is step one.
- 28:44That's what you want a model to do.
- 28:46Okay. But
- 28:50and this should be the intuition. I
- 28:51won't go through it again, but it's on
- 28:52that slide if you want it again. It's
- 28:54essentially that it removes the
- 28:56political advantage of being the
- 28:57incumbent because now you can be
- 28:59challenged by anyone and the group
- 29:01doesn't lose power. Okay,
- 29:04but here's a non-obvious prediction. The
- 29:07model says the effects of reservation
- 29:10are governed by this initial difference
- 29:12between what would happen if you threw
- 29:14someone out and if you keep them. So if
- 29:17you had a very very take a strong group,
- 29:19a very strong group, they were
- 29:20guaranteed to win in any case.
- 29:23So in that case, these numbers, these
- 29:26gamas are close to one. That is, if they
- 29:28were strong, even if they threw a guy
- 29:29out, wouldn't matter. They were probably
- 29:31going to win anyway. In that case, a
- 29:33reservation is not going to have much
- 29:35effect because a reservation collapses
- 29:36this difference. But if the difference
- 29:38was small anyway, it's not going to do
- 29:39much. If you took a very weak group,
- 29:42they were very unlikely to win again.
- 29:44And then a reservation would also have
- 29:46little effect. So what this is telling
- 29:48you is there's a nonmonoticity. The
- 29:50model which was generated to explain the
- 29:53core correlation which is putting in a
- 29:56reservation improves governance tells
- 29:57you no no it's only going to happen if a
- 30:00group is like in the middle size where
- 30:02it could compete for power but it's not
- 30:04guaranteed to win it. That's where you
- 30:06should find it.
- 30:08So that tells you well if I can observe
- 30:10these things then I can test this model.
- 30:14I can test whether this story is the
- 30:15right story. And we can, you know, we
- 30:20could just basically look in unreserved
- 30:21villages and say, what is a what is a a
- 30:23group that is going to win for sure?
- 30:25What is a group that is almost never
- 30:26going to win? And here it is. If you had
- 30:29less than 25% of the village village
- 30:31population in your group, you won about
- 30:332% of the time. So then you're one of
- 30:35these groups that's almost never going
- 30:36to win. If you're above 50%, then you
- 30:40kind of have a plurality. You're almost
- 30:41always going to win. It's these groups
- 30:43in the middle where you should see it.
- 30:44So we could classify
- 30:46village structures, population
- 30:48structures and say here's the
- 30:49reservations that should really be
- 30:51driving our correlation in the data.
- 30:54And that's what happened. We we measured
- 30:56a bunch of observations uh different
- 30:59types of government governance uh
- 31:01quality effects and we found that the
- 31:03effects were only positive in these
- 31:07villages
- 31:08in the ones where that population of the
- 31:10reserve group was a particular size. if
- 31:12it was bigger or smaller in those
- 31:14extremes, it had no effect. So the the
- 31:17model hetrogenity was exactly what we
- 31:20saw in the data. We had no idea that
- 31:22this was going to be the case. We were
- 31:24just fishing around looking for models
- 31:26that could explain it. And when we found
- 31:28this one and we found the extra one,
- 31:29then the model generated a huge amount
- 31:32more value. And I started to believe it
- 31:34at that point. Before it was just a
- 31:36story, then I start believing it. There
- 31:38was another set of predictions which we
- 31:40also tested and I'm not going to go
- 31:43through them because I want to move on
- 31:44to talking about modeling more in
- 31:45general. Okay.
- 31:48So what did the modeling actually add
- 31:50here? What the modeling added was
- 31:57an explanation
- 31:59which came from totally left field. Like
- 32:02it wasn't the explanation that we
- 32:03thought would have been true.
- 32:06But when we started thinking about it
- 32:07and had to do stuff with it to make it
- 32:09fit our context, we found this other set
- 32:12of predictions and they fitted. They
- 32:14actually told us they they made us run
- 32:17regressions we would never have run
- 32:18before. We had no idea xante that this
- 32:20is what we would end up with
- 32:21empirically. But when we did them, they
- 32:24made sense. They made sense in the data
- 32:26and they started to give us a richer
- 32:28understanding of the original
- 32:29correlation that we that we built. Okay.
- 32:33So the model formalized the story and
- 32:36made predictions and then it took us way
- 32:37further than we could ever have gotten.
- 32:40Okay. So this is the model exercise in
- 32:43full a little bit more. I'm filling in a
- 32:45few more arrows here. We have an
- 32:47empirical puzzle. Essentially we don't
- 32:50we're not theorists in the sense of
- 32:52we're coming up with wholly different
- 32:53mechanisms. I mean some of you will do
- 32:55that at some point but mostly that's not
- 32:57the case. You just borrow a mechanism
- 32:59from one of these canonical models or
- 33:01from something else and then you throw
- 33:02out the bits of it that are built for
- 33:06the generality of the problem. A lot of
- 33:07them are not going to be relevant in
- 33:08your context.
- 33:10You're going to indogenize and and
- 33:12enrich the bit whether your data is rich
- 33:14and that will often depend on the
- 33:15institution. You'll solve the model.
- 33:17You'll derive conditions and some
- 33:19predictions from it. You construct then
- 33:21new data. You'll be driven by the model
- 33:23to look for new things and you test
- 33:25again. And that's what I mean by applied
- 33:28political economy modeling. And it may
- 33:31not seem obvious to you. It's very
- 33:32obvious to me that this is exactly what
- 33:34we do when we move from first learning
- 33:38about economics, which is essentially we
- 33:40build models, these very abstract
- 33:42things, and then we start thinking about
- 33:43the empirical. We don't do it the other
- 33:45way. I mean, you'll notice when you
- 33:47first do econ, you don't start with
- 33:49econometrics. You start with models.
- 33:53Okay. So, what's a toolkit here? Okay.
- 33:56So, so once you've seen one example then
- 34:01and once you've worked with this a few
- 34:02times the models become very easy to
- 34:04apply and again they're not a list of
- 34:06papers to memorize but when you're
- 34:09familiar with these models these are the
- 34:10ones that I'm telling you I think have
- 34:12useful structures that come up a lot in
- 34:15political economy contexts and the great
- 34:17thing about them is they're old so
- 34:19they're easy to read right they're
- 34:20written in a way that's you know often
- 34:23the first paper in in an area they have
- 34:24to do a lot of the handwaving and a lot
- 34:27of the contextual structure for you and
- 34:28they build it in a simple way so you can
- 34:30see the mechanisms clearly. If you
- 34:31understand these mechanisms, they're
- 34:32going to give you a set of tools that
- 34:34will be useful in lots of empirical
- 34:36context. These are the I'm just putting
- 34:38them
- 34:40these are the ones that were on the
- 34:41second slide. At at the end of the
- 34:43slides, I'm going to give you the
- 34:43precise uh readings for these, but I
- 34:46think these were shared with you anyway.
- 34:47So again, you don't need them for every
- 34:49model. You need to recognize when some
- 34:52of the structure in these models is
- 34:54coming up in an empirical problem. And
- 34:56sometimes multiple models will have
- 34:59a role in a in a particular empirical
- 35:01problem. All right? So they're not
- 35:05things you need to memorize, but they're
- 35:06like you could think of them like spare
- 35:08parts. Okay? You don't want to copy the
- 35:10structure of any particular one. So you
- 35:11don't want to rebuild that whole car,
- 35:13but you know, you want might want to
- 35:14take a part of that car. So it's a piece
- 35:17of machinery that helps you explain some
- 35:19fact that seems to be popping up for you
- 35:21in the data.
- 35:24Okay. So you you also and and you are
- 35:27you should and you will cannibalize
- 35:28models, right? So you'll take bits of
- 35:30them. You take bit of say this is just
- 35:31an example the par baron fedon
- 35:33bargaining model with a contest
- 35:35technology. That's a paper that that
- 35:36that you know that I built and and
- 35:39worked with others on to to to explain
- 35:41power sharing in in in African politics.
- 35:44Um and there's a bunch of other ways to
- 35:46put these things together. So you pull
- 35:47from different parts of these models to
- 35:49build your own model. Okay. So all also
- 35:52it's some of these models are really in
- 35:54a context got nothing to do the one that
- 35:56you're going to be studying empirically.
- 35:57So the corid soil model is a sort of a
- 35:59sender receiver model about
- 36:03asym asymmetries in information and how
- 36:04that affects signaling and and
- 36:06interpretation of signaling. This is not
- 36:08really couched as a political model. I I
- 36:11don't think in that paper that was even
- 36:12talked about in a political context. But
- 36:14this is an architecture that's really
- 36:16useful for thinking about a bunch of
- 36:17political economy interactions between
- 36:19parties and voters, bureaucrats and
- 36:21politicians, experts and citizens and
- 36:23lobbyists and policy makers because you
- 36:24can see in all those context there's
- 36:25that core essential information
- 36:28asymmetry and knowledge asymmetry and
- 36:30and that affects how signals are sent
- 36:32and how they're interpreted.
- 36:34Okay. So, so, so let me just kind of
- 36:36talk a little bit at overview level
- 36:38about um
- 36:41elements of the modeling, right? So,
- 36:42these are that was the kind of the
- 36:44political economy context. Now, there's
- 36:46kind of some some more general
- 36:47questions, right? So, so one first
- 36:49question is um how much model do you
- 36:51need? Right? So,
- 36:54if your model explains the mechanisms,
- 36:57generates predictions, tell you what
- 36:59tells you what to collect, then that's
- 37:01maybe enough. You should stop. And
- 37:04there's a question of parimony in in
- 37:06applied modeling that's very different
- 37:09in its in how you judge it relative to
- 37:11thinking about pure theory. Um so so I
- 37:16mean the way I think of it is in
- 37:19applied theory I'm always thinking what
- 37:21do I need minimally to get to the data
- 37:23and do interesting things with the data.
- 37:25In a true theory paper and a lot of the
- 37:29papers that are canonical models are
- 37:30written more like that. They're really
- 37:32looking for the generality of the
- 37:34result. How general is it? You know,
- 37:37when does it hold? When does it not
- 37:38hold? You know, really exploring
- 37:43the limits of the story. And sometimes
- 37:47that is going to be something useful for
- 37:48you because you can get predictions off
- 37:49that. But often all of that generality
- 37:52which is how we would judge a good
- 37:55theory paper like you know has it really
- 37:58fully illuminated the mechanism what's
- 38:00necessary what's sufficient that's not
- 38:02what you need in an applied paper. You
- 38:04just need
- 38:06a believable story that rationalizes the
- 38:10correlation. You need to make it clear
- 38:12that it's not your it's not being bought
- 38:14by some sort of cheap assumptions in the
- 38:16structure. But you can use very simple
- 38:18assumptions like even quadratic form or
- 38:20something. If it's clear that that's not
- 38:22what's buying it, that there's a deeper
- 38:23intuition, then you can generate the
- 38:25results from that. So that wouldn't fly
- 38:26as a theory paper, but as an applied
- 38:28theory paper, that's exactly the level
- 38:30you want to be at. You don't want to do
- 38:31all that machinery for nothing. Okay. So
- 38:34when do you need more structure? So this
- 38:36is
- 38:38well, we'll think about what structure,
- 38:39what I mean by structure in a second. So
- 38:41So if you want to ask questions like
- 38:42this, what happens if you were to
- 38:44fundamentally change the system? change
- 38:46the voting rule, change a term limit. So
- 38:49you might put in a term limit when there
- 38:51aren't term limits for political office.
- 38:53Um you want to change who's eligible to
- 38:55stand. What happens essentially under an
- 38:58institution that you never observe in
- 39:00the data.
- 39:02So now the observed reduced form
- 39:06relationships aren't going to be enough
- 39:07because you're not observing these
- 39:08things. But if you can believe that some
- 39:11of them are invariant to these changes
- 39:13and this is where you have to make the
- 39:14assumption and and find it believable
- 39:17then you can run counterfactuals
- 39:19along these lines under the assumption
- 39:21that the parameters that you estimated
- 39:24initially in the data will hold across
- 39:27the counterfactuals. So that's when you
- 39:29can do structural modeling and that's
- 39:30when it's worthwhile to do it. So here
- 39:33you're going to make assumptions that
- 39:35will essentially be stronger than in the
- 39:38simple reduced form world. But with
- 39:40those stronger assumptions, you're going
- 39:41to be able to get more results. Results
- 39:45about things that would be more like
- 39:46systemic change. Now that comes at a
- 39:50cost. The cost is those assumptions.
- 39:53So those are stronger claims, right? So
- 39:56you're you're starting from primitives
- 39:58that you are taking much more seriously
- 40:00and actually much more literally, right?
- 40:02So preferences, technology, information,
- 40:04institutions, stocks, all those things
- 40:05are things that are now going to
- 40:06generate your equilibrium.
- 40:08So you're actually going to generate the
- 40:10data with your model. You're generating
- 40:14a rationalization of the data from your
- 40:16model. And you're going to be when it's
- 40:17useful is when you can hold those
- 40:19primitives, at least some of them fixed.
- 40:22So primitives on preferences,
- 40:23technology, and claim that those things
- 40:24are going to be invariant to the the try
- 40:26to change that I'm imagining. then
- 40:28you're going to get predictions about
- 40:29the world that would happen in that very
- 40:32different counterfactual world and that
- 40:34can be useful when when people will buy
- 40:36when you buy and when people will buy
- 40:38that those things are invariant
- 40:40and if they won't then it's a useless
- 40:42exercise right so so I've certainly met
- 40:45people who argue for doing this sort of
- 40:47structural work for or not doing it for
- 40:49the wrong reasons right so I I mean
- 40:52maybe people don't do this anymore but
- 40:54when it was when I was in grad school I
- 40:56heard people saying this structural
- 40:57models are just better because they're
- 40:59more rigorous. They, you know, they they
- 41:01have more math. There's more theory.
- 41:02They take theory seriously. That's not a
- 41:04good reason to do it. To me, the good
- 41:06reason to do it would be, oh, if I can
- 41:08actually understand something that I
- 41:10couldn't understand by doing the simple
- 41:11reduced form model, that's a good reason
- 41:14under a set of assumptions that people
- 41:15find believable, then okay, then it's
- 41:18worthwhile doing. And some people just
- 41:21start with an exit position that oh
- 41:23taking this like assuming preferences
- 41:25like nobody knows what the preference
- 41:26you can't just assume that structural
- 41:28models are never believable. I find that
- 41:30also an un an unconvincing reason to not
- 41:33do it. So I think they're they're both
- 41:35the wrong way to proceed. You should ask
- 41:37what question can I answer with the
- 41:39additional structure that I cannot
- 41:40answer without it? If none not at all
- 41:43then the question is is that structure
- 41:45believable? believable enough in
- 41:48believable enough to be invariant. Okay,
- 41:50then then it's worth doing.
- 41:54Okay, so that's my two cents on
- 41:57structural modeling when to and when
- 41:58not. And for me as an applied theorist,
- 42:01I've done both and in different contexts
- 42:03I think they're useful. Okay, so now
- 42:07this has changed things a lot. So LLMs
- 42:10have changed the technology of model
- 42:13building and they've changed it in
- 42:16mostly a good way and you should utilize
- 42:20them. I utilize them. They are useful
- 42:22for building models. The latest
- 42:24generation are two years ago. They
- 42:26weren't. A year ago they weren't that
- 42:27much. Now they're pretty useful. They're
- 42:30not perfect, but they do these things
- 42:32pretty well. You need to check them. But
- 42:34this is what they can do well. They can
- 42:35do algebra. And for someone like me that
- 42:37is just my life was littered with
- 42:41algebra errors. So I would for me
- 42:44algebra is a statistical process. What I
- 42:46mean is I do things five times and if
- 42:47two of them are the same then I would
- 42:49assume that that was the right one. So
- 42:51I'm terrible at algebra. So this made my
- 42:53life so much better. Right? So now I can
- 42:56just check it. I check one it looks
- 42:57right. I'm so happy. Derivations
- 42:59comparative statics trying alternative
- 43:01functional forms. So exploring elements
- 43:03of the model space that would have taken
- 43:04a long time. You can do it easy checking
- 43:07candidate models, generating several
- 43:09modeling approaches quickly. So you have
- 43:11some vague ideas, you put it in, it
- 43:13gives you some structure and you can
- 43:15think is this capturing it well or not?
- 43:17If it is, then you can say, well, you
- 43:18know, what are the things this is giving
- 43:19me? You can do this fast now. This is
- 43:21fantastically valuable. It's an enormous
- 43:24improvement in our research technology.
- 43:27So what's become scarce? Something has
- 43:29become scarce now. So if models can
- 43:31generate
- 43:33many at one time like 10 at once
- 43:37then the scarce input becomes what it
- 43:40becomes actually thinking and and you
- 43:42can't see thinking where do you see it
- 43:44where do you see the effects of it it's
- 43:45good judgment
- 43:47so building intuitive parimonious real
- 43:52illuminating defensible to you and by
- 43:54you models it's not always good at doing
- 43:58that so that you are still very much
- 44:01involved in the loop. So, it's giving
- 44:02you a sort of a a big leg up over a lot
- 44:06of elements of the model building, but
- 44:08it's not taken us um primates out of the
- 44:11model building process yet.
- 44:15Okay? And and and you can see like we
- 44:17used to be at least when I was in grad
- 44:19school, we were we I was impressed by
- 44:20people's mathematical capacities. Not
- 44:22just because, you know, there's this
- 44:24kind of thing that a lot of economists
- 44:25have, which is like if you if you're
- 44:26math, you're just smart. It was because
- 44:28they could explore the model space very
- 44:30fast. They could explore this kind of
- 44:32weird world, right? This abstract space
- 44:34of modeling. If you're good at math,
- 44:36that's the language of models. They
- 44:37could explore it fast and that's
- 44:38valuable. So, that was impressive.
- 44:40That's not impressive anymore. Okay. So,
- 44:42now we're increasingly asking, you know,
- 44:44why why are you building this
- 44:45complicated machinery? What's the
- 44:47algebra doing? Is it worth doing? Why
- 44:49couldn't things be simpler? And and more
- 44:51importantly, what do you actually
- 44:53believe? What can you defend?
- 44:57Okay. So, you have to own your model.
- 45:01That means what? You should use the LMS
- 45:03to build them. Absolutely, you should.
- 45:04And I put should in capital letters cuz
- 45:06actually you're wasting time if you
- 45:09don't. I think you should. And I don't
- 45:12know where that should be inserted. It's
- 45:14different for everyone, but I think they
- 45:15they are a valuable tool. We should be
- 45:17using them. But if it helps you build
- 45:18the model, by the time you present it,
- 45:20it still has to be your model. So you
- 45:22should know why every assumption is
- 45:24there, what results depend on them, what
- 45:26happens if you pull something out,
- 45:29why you rejected alternatives. You have
- 45:31to thought through all the alternatives
- 45:32and why you rejected them. Okay? It
- 45:34should become something like, you know,
- 45:35when you when you have a very good
- 45:36friend, you know them so well. You know
- 45:38how they'll react even in situations
- 45:40that that you haven't seen them in. you
- 45:42just know, oh boy, if you know, I know
- 45:43what they're going to do here even
- 45:44though I have, you know, that's that's
- 45:46the way you have to know your model. It
- 45:48has to be completely familiar to you.
- 45:52So that's the test, right? And this is
- 45:54the test that's increasingly becoming a
- 45:56big part of our profession. We using it,
- 45:58I'm using it all in my grad courses now.
- 46:00It's actually getting up and presenting
- 46:02your model and defending it against
- 46:04questions like this and worse questions
- 46:06and more difficult questions that you
- 46:08get. Why do you need that assumption?
- 46:09Why is information private? Why was this
- 46:12the sequencing? What happens if I change
- 46:13the sequencing that seems arbitrary?
- 46:15Couldn't another mechanism generate the
- 46:17same fact? Have you thought about that
- 46:18other mechanism? What do you think about
- 46:20it now? What happens if I remove
- 46:22something in the model?
- 46:25That intuition has to be very clearly in
- 46:28your mind. And you can't just say, well,
- 46:29that's in the appendix, right? That now
- 46:32it's it's even worse than it used to be
- 46:34if you said it because now it just makes
- 46:35it look like, well, you actually didn't
- 46:36generate your model. You don't own it.
- 46:39And here's the last bit. very important.
- 46:42LLMs are not good at attributing. Okay?
- 46:46So, they will take they will do what I
- 46:48said to you, right, which is cannibalize
- 46:51a model and give you something that's
- 46:53useful, but they don't tell you what
- 46:54model they cannibalize. They're very bad
- 46:56at that. You have to really push them to
- 46:59do it. And so, that may just be a a bug
- 47:04and that might be changed through time
- 47:06as the LM become better, but right now
- 47:08that's the case. So, so you can say,
- 47:11"Oh, I've got this vague idea from a
- 47:13model." And it goes, "Hey, yeah, like I
- 47:14I think this is what you should do." And
- 47:16it gives you a formalization that's just
- 47:18completely lifted from someone else,
- 47:20right? Who also had the vague idea maybe
- 47:22in a different context. You have to site
- 47:23that paper. You have to push the LM to
- 47:26tell you what is this like, where did
- 47:28you get this? Is does it resemble
- 47:30anything? You have to push it hard right
- 47:31now for it to give you that information.
- 47:33And if you don't and if you take a model
- 47:36that someone else's that the LLM gave
- 47:38you, you are responsible for that. And
- 47:40that is plagiarism, right? You're
- 47:42responsible ultimately for that. So you
- 47:44have to do a deep dive and make sure
- 47:46that whatever it's giving you, you go
- 47:48and find the paper and you read that
- 47:50paper and you site it properly. Okay? If
- 47:52not, then I put that in bold at the end.
- 47:55I have seen careers ended by that sort
- 47:57of not not in the LLM context, it's too
- 47:59early, but by plagiarism. Okay?
- 48:02you that's the one thing you don't want
- 48:03to be. You have to be correctly
- 48:05attributing. Okay.
- 48:08Okay. So let's me go to sort of the over
- 48:10overview level a bit.
- 48:12These are five questions to ask when you
- 48:13have a new empirical result. What is the
- 48:15simplest economic environment that could
- 48:17generate that fact?
- 48:20You have to think about what should be
- 48:22primitive? What should emerge? And those
- 48:23canonical models in particular contexts
- 48:25are going to help you that they're
- 48:27exactly doing that. Then what else has
- 48:30to be true? If the mechanism that I'm
- 48:33I'm suggesting is the one that works,
- 48:35what has to be true if that's correct,
- 48:38then think about more broadly what
- 48:40competing mechanisms could explain the
- 48:41same fact and what data would help you
- 48:43to distinguish between them. And then
- 48:46when do I stop? Do I have enough model?
- 48:49Is there something else I can get for it
- 48:51from it? Maybe then I could maybe if I
- 48:53want to look at a different sort of
- 48:55world that might be an important policy
- 48:56world, maybe I want to put more
- 48:58structure in. These are the questions
- 49:00that come to me when I do model
- 49:04building. And like I said, I mostly work
- 49:07with empirical people who come to me
- 49:09with I mean there's two sorts of
- 49:11situations that I kind of do this model
- 49:13building for. One is with students. So
- 49:15it's it's remarkable. We used to learn
- 49:17this kind of skill because a lot of the
- 49:19fields were much more theoretical. So we
- 49:21would see these canonical models and
- 49:23work with them. Now so much of the work
- 49:25and this is a good thing but we have
- 49:27evolved towards doing much more
- 49:29databased work. So many students will
- 49:32just have they're swimming in data and
- 49:34have a bunch of correlations and then
- 49:36they come to people like me and say my
- 49:39supervisor said I have to come up with a
- 49:41story to rationalize this and you know
- 49:44that's good but the story can be much
- 49:46more than just a rationalization and it
- 49:48should be otherwise and I see this a lot
- 49:50people are just putting in math what
- 49:52they could put in English and calling it
- 49:53an empirical model it's totally useless
- 49:56you might as well just say it in English
- 49:57the model has to do the work of
- 49:59generating something new for you
- 50:01empirically, not just rationalizing the
- 50:04fact.
- 50:06So, so what I want you to leave this uh
- 50:09talk with and I'm happy to take Q&A, but
- 50:11here's the kind of um
- 50:15questions that I and the thinking that I
- 50:17want you to take away. So, so when you
- 50:19see an empirical pattern, you shouldn't
- 50:22think the first thing shouldn't be you
- 50:24thinking what regression should I run
- 50:26next. um should also ask what's the
- 50:30environment that generated this
- 50:31empirical pattern
- 50:34and that's going to tell you what else
- 50:36you should run next. That's going to
- 50:38tell you what that particular
- 50:40environment those moving parts
- 50:44are generating empirically and then you
- 50:45go and run that. So, so like with supply
- 50:48and demand, right? If you just saw a
- 50:50bunch of correlations between quantities
- 50:51and prices, you could think about, okay,
- 50:54maybe I should run a sort of a different
- 50:56specification. Maybe I should put in a
- 50:58squared term or something. It's totally
- 51:00useless to do it that way. But when you
- 51:02start thinking about supply and demand,
- 51:03when that's deeply embedded into how you
- 51:05think about that context, then it gives
- 51:07you a different structure. Now I'm
- 51:09thinking, oh, well, what are things that
- 51:11could move the supply curve maybe
- 51:13exogenously that would allow me to
- 51:15identify the demand curve? It totally
- 51:17structures how you think. So that way of
- 51:19thinking which I think is deeply
- 51:21embedded how we think about
- 51:23the most simple context should be
- 51:26embedded in how we think in political
- 51:27economy context as well. And what I'm
- 51:29suggesting is those canonical models
- 51:32give you that set of tools for thinking
- 51:34that way. They're just like the supply
- 51:36and demand of the standard market.
- 51:40So the objective is essentially is to
- 51:42move from an empirical fact.
- 51:46This is the correlation that you found
- 51:48set of facts and
- 51:51think about the story which is the
- 51:53economic mechanism. Then build a model
- 51:57use whatever tools you need to do that.
- 51:59But you have to own it.
- 52:02That model should give you new things to
- 52:04look for in the world. And when you
- 52:07found those things, if they fit, then
- 52:09you actually have a paper. If they don't
- 52:11fit, tells you that's not a good model.
- 52:12Go back and think about it again. So, it
- 52:15all comes from this this position that,
- 52:18you know, I have um which is a kind of
- 52:20an an act of faith in a sense, right?
- 52:23It's like I think that the economic way
- 52:25of thinking actually does generate
- 52:27insights into the world. So if I find a
- 52:31set of correlations that don't make
- 52:32sense, I try to think of them with a an
- 52:35economic model and if that model
- 52:37generates predictions and they fail,
- 52:39then I don't say, well, this is just a
- 52:41mystery. We'll never be able to
- 52:42understand it. I think no, there
- 52:43actually must be a different model. And
- 52:45I will keep exploring the model space
- 52:48till I find the one that makes sense.
- 52:50And in fact, the best thing is if the
- 52:52first five models don't work, they
- 52:54generate predictions that don't work,
- 52:55then you've got a super interesting
- 52:57motivation for a paper, right? It's
- 52:59like, look, you may think it's X. Well,
- 53:01model X generates this and that just
- 53:03doesn't fit. You may think it's Y. Then
- 53:05you can say, here's my model, which is
- 53:07this super weird funky thing, but that
- 53:09actually fits. Then you've got a great
- 53:12paper. So
- 53:16I think political economy is for that
- 53:19process. Political economy is a set of
- 53:22theories firstly explanations for the
- 53:24world that we use to generate deeper
- 53:28ways of going into the world into the
- 53:32data.
- 53:34Okay. So those are the papers I think
- 53:36the reading list has been circulated
- 53:38with you but I that I think are great
- 53:39papers to read that have helped me a lot
- 53:41in thinking about different political
- 53:43economy contexts. Um I think uh I that's
- 53:48really all I wanted to say. So that's
- 53:50I'm now happy to take questions and I
- 53:52think Caleb's going to moderate the
- 53:53questions and um just far away. I can
- 53:57stop screen sharing Caleb.
- 54:00>> Sure. Yeah, that that works great.
- 54:02>> Okay.
- 54:06So, uh if anyone has questions, they
- 54:09there's many that have been coming in
- 54:11through the Q&A box, but now's a good
- 54:13time to send through any more for for
- 54:15Patrick if you have them. I'll start
- 54:17with what we have and we'll
- 54:20begin with uh the live participants here
- 54:23and we'll just kind of go back and forth
- 54:24like we have in in the other lectures.
- 54:27So um I'm going to murder this. Kar Sara
- 54:31Van would you like to go first?
- 54:33>> Yes.
- 54:33>> Yeah. Uh hi Patrick thank you so much
- 54:35for the presentation. It's quite
- 54:36interesting. My question is related to
- 54:38the political reservations in um the
- 54:41village of Maharashtra that you spoke
- 54:43about like whether the the socioeconomic
- 54:46uh status of Pradhan influence the
- 54:49governance mechanism because since we
- 54:50work with village punays what happens is
- 54:53that these pradans they don't get
- 54:55salaries or like a proper hondorium. So
- 54:58my question is like on that context
- 55:01where does the socioeconomic status of
- 55:04Pradan makes sense or does it uh you
- 55:08know bring uh changes in the governance?
- 55:11>> So it's a good question absolutely and
- 55:13and especially in that context. So um
- 55:16but let me just kind of because I think
- 55:18it's a it's sort of a little bit uh a
- 55:21very specific question that's not
- 55:22related to the overall theme of the
- 55:23lecture. I wanted to give that as an
- 55:24example but I think there is something
- 55:26related to the theme of lecture in your
- 55:27question. So I want to kind of touch on
- 55:29that. So in that context one of the
- 55:32first things we thought was look the
- 55:34type of person that's getting the office
- 55:36now is going to be different than the
- 55:37type before and that's going to be
- 55:39related to social economic status
- 55:41education maybe landholding maybe uh
- 55:45wealth in other ways you know
- 55:47we found and that was the first place we
- 55:49looked. So you know when we saw this
- 55:51pattern of reservations acting in a
- 55:53certain way we found that to be
- 55:57unimportant. So we we we had pretty good
- 55:59measures of it and it just wasn't moving
- 56:01the variables at all. So so that was one
- 56:04of the things we conjectured. So in a
- 56:05sense that's a theory that we explored
- 56:07in a very preliminary way with the data
- 56:09and ruled out pretty quickly. And also
- 56:12when we once we had developed our theory
- 56:15it generated this non-monotonicity
- 56:16prediction. And then we went back and
- 56:18thought well look maybe we just didn't
- 56:21measure those observables about predan
- 56:23type very well if we had measured them
- 56:25maybe there's mismeasurement there maybe
- 56:28that is still important could that
- 56:30generate the nomotenicity so we thought
- 56:32through that theory we resurrected it
- 56:33again thought could it explain our data
- 56:35and it didn't generate it so it actually
- 56:38failed in terms of the empirical
- 56:40observables and then once we had the the
- 56:42kind of interesting extra results from
- 56:43the other theory which were confirmed in
- 56:45the data we went back to that theory and
- 56:47it also didn't make of it. So, so it
- 56:49comes up a lot when you know and this is
- 56:50one of those things when we gave the
- 56:51talk people like oh no they had your
- 56:54intuition that this might be an
- 56:55important thing and we could rule it out
- 56:57for those two reasons. One is it didn't
- 56:59fit in in our raw data it just wasn't
- 57:02doing anything but two even it would be
- 57:04very hard to rationalize our empirical
- 57:06finding with that story. So that that
- 57:09seemed to me that was kind of very much
- 57:11part of the modeling process is to
- 57:13consider theories like that one and
- 57:14others in in context. Yes.
- 57:17Good question.
- 57:18>> Thank you.
- 57:20>> Perfect. Um, there have been a few
- 57:23questions in in the chat kind of I think
- 57:27going back to what you were saying more
- 57:28about the beginning around kind of where
- 57:31you getting your data from and what the
- 57:32role of theory is. And I I think many
- 57:35researchers um are told that you can
- 57:38either you know start with a big theor
- 57:39theoretical question and then seek
- 57:41evidence and others are told to begin
- 57:43with that empirical pattern or work
- 57:45backwards towards a mechanism and so in
- 57:48your own work maybe how do you move
- 57:50between theory and data and what
- 57:52distinguishes a productive interaction
- 57:55>> yeah so uh okay so I think it's very
- 57:58risky to start with I had this theory
- 58:02about the universe
- 58:04and I'm going to formalize it and uh
- 58:08then it's going to generate some
- 58:09predictions and it's going to take me
- 58:11like a year or two to formalize it and
- 58:13then uh I'm going to look for data.
- 58:16Maybe there'll be some data that could
- 58:17speak to it and uh and then and
- 58:21hopefully the data fits. I mean that's
- 58:23just like a fantastically
- 58:25scary undertaking I think for a PhD
- 58:28student, right? Like, so once you're me
- 58:30and I got tenure, then I actually do do
- 58:32things like that now, right? I mean, I
- 58:34it wouldn't be my whole job because if I
- 58:36if that was the only thing I did, I'd
- 58:37feel embarrassed cuz for 10 years I
- 58:39wouldn't publish, right? And then maybe
- 58:40I publish something. So, but I do I have
- 58:43these things going on in the background.
- 58:44So, I wrote a paper recently on
- 58:45consciousness, right? Which is like
- 58:47totally wildly not economic and it was a
- 58:50form of that. It's a pure theory piece.
- 58:52But I find that as if an applied
- 58:54theorist, I mean, there are people who
- 58:56are doing theory and they're making the
- 58:57tools that we think that's fine. And I'm
- 58:58not talking about that for the applied
- 59:00theorist who's trying to explain
- 59:00something in the world, I think it's a
- 59:02very risky way to start. So, so that
- 59:04kind of stylized conception that we come
- 59:06up with a a theory and it's kind of
- 59:08sealed and then we we we we look at we
- 59:12fully, you know, instantiate that theory
- 59:14in a model and then we look for data to
- 59:16test it. That's that's not really how
- 59:19this process can work. I just don't
- 59:21think it's feasible. What I think is
- 59:22feasible is
- 59:24the world now throws up a lot of data in
- 59:28a way that it didn't when I was in grad
- 59:29school. So now you can just create data
- 59:31sets so quickly and you can access data
- 59:33sets so quickly and most of that data is
- 59:36in the social realm. So it's really
- 59:38begging for theoretical economic
- 59:40explanation. So that's the way it
- 59:43usually works. You come up with data,
- 59:44you find these interesting things.
- 59:47Sometimes it can really establish great
- 59:49causal relations. So it fits all the
- 59:51kind of tests of um identification. Then
- 59:54you think about what what does it mean?
- 59:57How do I explain it? And if if that
- 1:00:00process is rich, what I mean is that
- 1:00:03story which will rationalize it will
- 1:00:05give you more things to look at in the
- 1:00:06data and then you have a great project.
- 1:00:08Because I'm always thinking when I'm
- 1:00:11doing a project, how am I going to stand
- 1:00:13up in front of a room of skeptical
- 1:00:14economists who each have their own ideas
- 1:00:16which are not the same as mine and
- 1:00:18convince them that this is something
- 1:00:20that's worth an hour and a half of their
- 1:00:22time. And it's like that here's this new
- 1:00:24set of facts that you didn't know about
- 1:00:26before. That's not enough. Cuz most
- 1:00:28people say, "Yeah, okay, big deal. What
- 1:00:29does it mean?" I tell them what it means
- 1:00:31and I defend it. So I say, "Look, you
- 1:00:34know, here's a way of making sense of
- 1:00:35it." And then they're like most
- 1:00:37economists there's 30 people in the
- 1:00:39room. There'll be 40 different opinions,
- 1:00:41right? No, no, this is not it. It's
- 1:00:42something else. It's this thing. God,
- 1:00:44how can you claim that? So people just
- 1:00:46come up and then you say, "Okay, here's
- 1:00:48my story." And it generates these seven
- 1:00:51other predictions. And your stories
- 1:00:53don't do that. I know that. I thought
- 1:00:54about some of them. They'd be very
- 1:00:56surprised if they did. And then they
- 1:00:58fit. Then you then you've taken somebody
- 1:01:00from skepticism to like, "Oh, yeah, so
- 1:01:04what?" to like, oh, that's kind of cool.
- 1:01:06I think it's just a human thing. We just
- 1:01:08like explanation. We like a story or a
- 1:01:10parable or myth that makes makes sense
- 1:01:14of the observables. And if I can say,
- 1:01:16look, this one seems to fit, then that
- 1:01:18that's just interesting to people. So, I
- 1:01:21think that that process is a better
- 1:01:22process for a PhD student is to take the
- 1:01:24the data first, enrich it with a story
- 1:01:27and a theory, and then do more data
- 1:01:30based on that enriching. That's that's a
- 1:01:32more feasible one. So I know it's not
- 1:01:33pure science cuz I think we have this
- 1:01:35pure science view. We we we come up with
- 1:01:37theories in the abstract like you know
- 1:01:40and then we just go and test them in the
- 1:01:41empirical world. I don't think that's
- 1:01:42how it is. It's a back and forth.
- 1:01:47>> Thank you. I think I think that really
- 1:01:49hits home to some of the the root of
- 1:01:51some of these questions.
- 1:01:53Assuming then that we do start with uh
- 1:01:56the data first and we're we're going
- 1:01:59from there. When several models appear
- 1:02:02that are consistent with the data, what
- 1:02:04do you use to decide amongst them? Do
- 1:02:07you prioritize predictive performance,
- 1:02:10parsimony, externability like h how do
- 1:02:12you how do you decide which out of all
- 1:02:13the models that come from your data to
- 1:02:16go with?
- 1:02:17>> Yeah. So sometimes, you know, I think
- 1:02:19it's a combination of things. So the
- 1:02:21reality is, you know, we have this view
- 1:02:22of like these Okams rays are the most
- 1:02:24parsimonious one, but sometimes people
- 1:02:26just find the parimonious explanation
- 1:02:28not to be real. So you know if they're
- 1:02:30really equivalent on observables at
- 1:02:32least you know there may be all models
- 1:02:35are going to have some differential
- 1:02:36predictions but in might be that those
- 1:02:38are in in realms that are not
- 1:02:39observable. So if they're equivalent on
- 1:02:42the observables
- 1:02:43then I think the right thing to say is
- 1:02:45look I have a class of models that vary
- 1:02:48on some dimensions that's why they're a
- 1:02:50class and they're going to differ on
- 1:02:51some of these but those differences
- 1:02:53are in dimensions that we just don't
- 1:02:56have the data to collect. I can I could
- 1:02:58tell you the experiments that you would
- 1:02:59need to run but you know it's not
- 1:03:01feasible for me as a student to run them
- 1:03:02but so I don't I don't wed myself to one
- 1:03:06of those particular ones because I don't
- 1:03:08have a good reason to do it at that
- 1:03:09point and I don't need to. If I say look
- 1:03:11it's a class of models and there may be
- 1:03:13variation on these at the fringes of
- 1:03:15those models that would be generating
- 1:03:17other predictions but I can't do them
- 1:03:18then I just say I commit to that class
- 1:03:20of models that class of models is
- 1:03:21generating a set of predictions that are
- 1:03:24in the data and that's what I'm going to
- 1:03:26tell you about. Now when I'm giving the
- 1:03:28narrative you know when you're giving a
- 1:03:30narrative on a model it's very hard to
- 1:03:31do a class of models because they're all
- 1:03:33a little bit different. Then I pick the
- 1:03:34one that I think isn't necessarily the
- 1:03:36parimmonious one. I usually pick the one
- 1:03:38that I think is the most compelling, the
- 1:03:40most compelling story. And and again,
- 1:03:42that's important, you know, like most
- 1:03:44people, I mean, we learn to not do this,
- 1:03:46but most people, at least when they
- 1:03:48approach a newspaper, they approach it
- 1:03:49like they do reading a newspaper
- 1:03:51article. Newspaper articles doesn't give
- 1:03:52you, it gives you a little bit of stats,
- 1:03:54but it's often with a narrative. So
- 1:03:55those compelling narratives, I think,
- 1:03:57are very important. But the but I think
- 1:03:59that's part of the pitch of a paper and
- 1:04:02a talk. But you know, in the end, if you
- 1:04:04have a class of models that are
- 1:04:06indistinguishable, you have to say, "No,
- 1:04:08no, all of those are on the table at
- 1:04:10this point. This is all I can do with
- 1:04:11the data. I can just tell you it's one
- 1:04:13of these or maybe all of these or some
- 1:04:15combination of these." But I So that's
- 1:04:17the right thing to do. But in terms of
- 1:04:18the pitch, you want to pitch the one
- 1:04:20that's the clear, cleanest story.
- 1:04:23Does that help?
- 1:04:25>> I can answer for them and say yes. Uh I
- 1:04:29hope so.
- 1:04:31If if not then they can say no. Um
- 1:04:35>> yeah uh whoever submitted that one if
- 1:04:37you have any follow-ups please send
- 1:04:39through and in the Q&A. In the meantime
- 1:04:41>> let me ask there's a there's Aman Ray
- 1:04:44has a has his hand up and I want to ask
- 1:04:46him a question because he's one of those
- 1:04:47very good audience members that smiles
- 1:04:49and laughs a lot. So um I I want to
- 1:04:51reward that with a [laughter] with
- 1:04:53asking is a lot of value added as a as a
- 1:04:56lecturer to seeing a sort of an animated
- 1:04:58uh so
- 1:05:00>> Andre you've been called upon.
- 1:05:02>> Yeah. Okay. Uh my question was actually
- 1:05:06so sometimes with these models what
- 1:05:08happens is some of the assumptions they
- 1:05:11may not seem that realistic. For
- 1:05:14example, the hoteling downs model for
- 1:05:17like the one with the median water
- 1:05:19theorem, it assumes full voter turnout,
- 1:05:22right? But empirically that's not well
- 1:05:24observed. I mean empirically we don't
- 1:05:25observe that at all. And yeah, so when
- 1:05:29you relax these assumptions, maybe the
- 1:05:32original model predictions sometimes
- 1:05:34they don't hold up anymore. So what do
- 1:05:37you think of the canonical model in that
- 1:05:39cases like that? like when it's not
- 1:05:41robust to its assumptions being relaxed.
- 1:05:45>> So sometimes so I think it's important
- 1:05:47so I think you should you have to think
- 1:05:48about it. So if that critical assumption
- 1:05:51is changing something that's important
- 1:05:53for explaining the moments in your data
- 1:05:55then then then it's important that you
- 1:05:57actually get that assumption right but
- 1:05:58often it's not right. So often you're
- 1:06:01going to get this convergence result you
- 1:06:03know independently of whether there's
- 1:06:05full turnout or not. So you have to kind
- 1:06:07of decide whether that's important in
- 1:06:08your context but it could be you know
- 1:06:11when I think about it um so for instance
- 1:06:14you know Australia where I'm from you
- 1:06:17know I used to be from so I'm still
- 1:06:18anyway I'm still from there but I don't
- 1:06:20live there. um it has compulsory voting.
- 1:06:25So that element I think so my I guess
- 1:06:29someone else has said it but it's always
- 1:06:30occurred to me in Australia you have
- 1:06:33essentially parties that converge in the
- 1:06:35middle. You don't have any polarization
- 1:06:38because everyone votes. So they're all
- 1:06:40competing for the the median voter and
- 1:06:43it's because that assumption holds by
- 1:06:46institutional construction. If you don't
- 1:06:48vote in Australia you get fined a lot.
- 1:06:49it's compulsory.
- 1:06:51So now what we're seeing, you know, say
- 1:06:54in the US is you're seeing this
- 1:06:55polarization. Well, they're competing
- 1:06:57for those fringe voters. So that's
- 1:06:59clearly a violation of the assumption
- 1:07:01that everyone must vote. But that that
- 1:07:03that is exactly what's generating, I
- 1:07:05think, that polarization because now
- 1:07:07they're not competing over the middle.
- 1:07:08There's more to gain from activating the
- 1:07:10base on either side. So that's that's
- 1:07:12exactly the context. So if I was trying
- 1:07:14to explain Australia, it's not I mean
- 1:07:16some people don't vote. That assumption
- 1:07:18holds. and that generates a result. If
- 1:07:20I'm trying to explain, I can still use a
- 1:07:22lot of the insights of the hoteling
- 1:07:23model in the US context by adding the
- 1:07:28restriction by releasing the restriction
- 1:07:30that people are forced to vote. So, I
- 1:07:31think it just depends on the context and
- 1:07:34and you just have to get some things
- 1:07:36right because they're going to matter
- 1:07:37for the context. Other things you'll get
- 1:07:39wrong, but they don't matter for the
- 1:07:41context. So, you just go with the
- 1:07:43assumption because it's simple and
- 1:07:44parimonious. So you know the bottom line
- 1:07:46is if it's a big moving part in your
- 1:07:48model and it's being generated by an
- 1:07:49unrealistic assumption that's a bad
- 1:07:51model.
- 1:07:55>> Yeah. Thank you.
- 1:07:58>> Perfect. Um we have a couple more hands
- 1:08:00here. So maybe I'll do one more. Sanjo,
- 1:08:02do you want to ask your question
- 1:08:03briefly?
- 1:08:07>> Hey Patrick. Um as a PhD student I I
- 1:08:11just want to say like your lecture was
- 1:08:12absolutely brilliant. uh firstly and I'm
- 1:08:16like sort of in that applied modeling
- 1:08:18process at step two. So I've like
- 1:08:20collected data. I have some predictions,
- 1:08:24correlation, causation, whatever you may
- 1:08:25call it. And now I'm trying to build
- 1:08:27this model. And I think uh this is
- 1:08:30following up on Caleb's question about
- 1:08:33competing canonical models. But the
- 1:08:36struggle that I'm facing is that there's
- 1:08:39no very obvious canonical model in my in
- 1:08:44my case. So for instance, your model is
- 1:08:46a politician identity to citizen or like
- 1:08:48governance outcomes relationship model
- 1:08:52but I'm looking at a bureaucrat identity
- 1:08:54and um governance
- 1:08:58um so I see a bureaucrat as like a
- 1:09:00mechanism from going from the politician
- 1:09:04to the bureaucrat to to governance. So
- 1:09:08in that case, if your if your models to
- 1:09:11choose from are too different from each
- 1:09:12other, like they're not a class. They're
- 1:09:16quite different from each other. Like
- 1:09:18how would you navigate that?
- 1:09:20>> So, so just to be clear, so firstly,
- 1:09:22thanks for saying that. But just to be
- 1:09:25clear, um you have two different models
- 1:09:29that will generate the same
- 1:09:32essentially predictions in your data. Is
- 1:09:34is that that problem? and you're trying
- 1:09:35to distinguish between which one to use
- 1:09:38or is it that you're trying to take
- 1:09:40different components
- 1:09:42from two canonical models and decide how
- 1:09:45to put them together to generate your
- 1:09:49your explanation. I think it's it's the
- 1:09:51latter uh of of having one is an
- 1:09:54asymmetric information model which gives
- 1:09:56you certain kinds of predictions and
- 1:09:58another are these like identity based
- 1:10:00models which give you a certain kind of
- 1:10:03prediction and you're trying to you feel
- 1:10:05from your empirical predictions that
- 1:10:06these moving parts matter
- 1:10:09>> u but how do you how do you bring that
- 1:10:12together and like sort of like construct
- 1:10:14it? Yeah.
- 1:10:15>> Yeah. So those two, if I understand
- 1:10:17them, those two um components are not at
- 1:10:20odds. They could be built into one model
- 1:10:22and they could have both moving parts.
- 1:10:25And that's actually better, right?
- 1:10:27Because then you're contributing by, you
- 1:10:30know, amalgamating two freestanding
- 1:10:32models into one framework and generating
- 1:10:35predictions that are coming from
- 1:10:37different components of that framework.
- 1:10:39So you need them both to explain your
- 1:10:41data. I think that's a a good thing.
- 1:10:43That's a kind of a a richness. So it's
- 1:10:45saying look I can't and this is a good
- 1:10:47thing to do like especially you know
- 1:10:49we've all been in talks where somebody
- 1:10:51says now I'm going to give you the model
- 1:10:52and you just see you know pages of math
- 1:10:54and you're like oh my god you know so
- 1:10:57here's a motivation for people to do the
- 1:10:59work because you go look you you have
- 1:11:00this one model in mind that doesn't do
- 1:11:02the work and this other model which you
- 1:11:04also have doesn't but when I put them
- 1:11:05together and I have to do a bit of work
- 1:11:06to do that but when I put them together
- 1:11:08it's going to give us so much more
- 1:11:10richness
- 1:11:11so it motivates the modeling the model
- 1:11:14building process because neither one can
- 1:11:16is sufficient to to explain the data
- 1:11:18that you have. So to me, that's a good
- 1:11:20thing. It's not a I don't see an
- 1:11:21inherent tension in that. Where there's
- 1:11:23a tension is when they're they're
- 1:11:25actually at odds and you can't build the
- 1:11:26model because they actually have two
- 1:11:27very different moving parts. Then you
- 1:11:29kind of have to go with one or the other
- 1:11:30and then the data should tell you which
- 1:11:31one's doing better. Um so yeah, so I
- 1:11:35think that's the I think it's okay. I
- 1:11:37think that's not a huge problem. I think
- 1:11:38it's good. I think you should explore
- 1:11:40that richer model because you need it
- 1:11:41for the data. Um,
- 1:11:45>> thank you.
- 1:11:48>> Thanks, Sanjanna. I I think that uh I've
- 1:11:50certainly also seen papers where
- 1:11:52complementing models built on top of
- 1:11:55each other do provide more of a
- 1:11:57richness. Um, but there is another side
- 1:12:01and someone else has asked about this
- 1:12:03whether we we were talking about
- 1:12:05layering models. Now
- 1:12:08Patrick, do you think that having an
- 1:12:09explicit model always improves a
- 1:12:12political economy paper or are there
- 1:12:14cases where a plain English explanation
- 1:12:16is actually superior? Maybe you can draw
- 1:12:19on experiences both, you know, as a
- 1:12:21model and a consumer of research.
- 1:12:23>> Yeah. Yeah. No, great great um question.
- 1:12:26So uh if you can do it all in English,
- 1:12:30do it in English. So, I just don't think
- 1:12:34there's any point to putting in math
- 1:12:36something that just repeats and
- 1:12:38regurgitates the basic intuition that
- 1:12:41you already have in English. So, so I
- 1:12:43think a lot of papers just are fine to
- 1:12:47be just done as essentially it's it's an
- 1:12:50empirical result and here's the you
- 1:12:53already have implicitly in your mind
- 1:12:55probably what's going on and I'm going
- 1:12:57to tell you in English and that's fine.
- 1:12:58you don't even need the um the the
- 1:13:01theoretical model. So I think that's
- 1:13:03fine. Yeah. So often it is just the
- 1:13:05case. So I think when you're going to
- 1:13:07drag somebody through your formalization
- 1:13:10and a bunch of results,
- 1:13:13it has to be doing some work. So So by
- 1:13:16work I mean the distance between the
- 1:13:19assumptions and the results. I mean I
- 1:13:21used to have a uh a uh he was actually
- 1:13:26one of my supervisors Mckesh Ezarn and
- 1:13:29he used to say there has to be a
- 1:13:30gentlemanly distance between assumption
- 1:13:32and results. It means it just can't be
- 1:13:35that you know you're essentially just
- 1:13:36regurgitating your assumptions in your
- 1:13:38results. If if the model isn't
- 1:13:42generating
- 1:13:44insight. So what it means is when you
- 1:13:46throw these assumptions together, how
- 1:13:48come this result how come you get this
- 1:13:50result if that's if that's completely
- 1:13:52obvious you don't need to build the
- 1:13:53model probably you can just tell the
- 1:13:54story. If it's not obvious then you know
- 1:13:57they need to go through well here's
- 1:13:58here's the theorem here's here's how it
- 1:14:00holds together here are the conditions
- 1:14:03under which the theorem holds and that
- 1:14:04wasn't obvious and here's the extra
- 1:14:06prediction that wasn't obvious. All that
- 1:14:07stuff has to be non-obvious.
- 1:14:09I mean that's why you're dragging people
- 1:14:11through reading all your math. I mean we
- 1:14:13don't very few of us think in math right
- 1:14:15we mostly think in just narrative so
- 1:14:18whatever language it is English is the
- 1:14:20one we tend to write in so we just tell
- 1:14:21it in English I don't think you need a
- 1:14:23model for a lot of a lot of applications
- 1:14:28>> thank you um
- 1:14:32we'll go now to back to our kind of live
- 1:14:34panelists here Gagas would you like to
- 1:14:44You're muted mute there.
- 1:14:48>> All right. Thank you. Can you hear me
- 1:14:49now?
- 1:14:50>> Yes.
- 1:14:51>> Okay. Thank you so much for the
- 1:14:53beautiful presentation. I have a couple
- 1:14:55of questions anyway, but let me just
- 1:14:56push one for now. Um so you you talked
- 1:15:00about um the possibility of having um an
- 1:15:04amazing model so to say in a class of
- 1:15:07competing models right that could also
- 1:15:10pro provide you with the best result.
- 1:15:12But my question is what then happens in
- 1:15:14an instance whereby you pick a model
- 1:15:16which as far as you are concerned is the
- 1:15:18best model in that class of rival
- 1:15:20alternatives and yet you are having a
- 1:15:22challenge of fitting it into reality or
- 1:15:26reality into it. Okay, especially in the
- 1:15:30context of political economy where the
- 1:15:32data itself could be political. It is
- 1:15:34only as good as the political class
- 1:15:36tells you it is. I'm saying this um with
- 1:15:40a particular emphasis on where I'm
- 1:15:41coming from Africa for example that data
- 1:15:44may have integrity issues. So I'm asking
- 1:15:47what happens where your model is as far
- 1:15:50as you are concerned good the best
- 1:15:52perhaps but then there are issues with
- 1:15:54fitting it into reality or fitting
- 1:15:56reality into it and then how do I avoid
- 1:15:58the tragedy of forcing your model to
- 1:16:01confess the reality it was not built to
- 1:16:04to you know mirror and all of that. I'll
- 1:16:07be glad if you can assist. Thank you.
- 1:16:10>> Okay, good question. So, so that that um
- 1:16:13world in which I have my model that I
- 1:16:17think is a beautiful model and that I
- 1:16:19think fits and explains the world,
- 1:16:22but reality is getting in the way and
- 1:16:26saying, "Yeah, that model's not right."
- 1:16:27That's that's a world that I've lived in
- 1:16:29a lot. Um where I built complicated
- 1:16:32models and thought, "Yeah, these are
- 1:16:33this is such a cool model. So subtle.
- 1:16:37But that's useless. So you know if if so
- 1:16:41one part of it one way to think of it is
- 1:16:43if really reality just keeps saying no
- 1:16:46that just fails that just model isn't
- 1:16:48working then you just have to throw that
- 1:16:50model out even though it might be the
- 1:16:51most beautiful thing because I mean
- 1:16:52ultimately we're not artists right we're
- 1:16:55we're trying to explain the world
- 1:16:57but so so if at that level of your
- 1:17:00question I think yeah it's awful the you
- 1:17:04know our models don't always work and I
- 1:17:07wish the world was better but it's not
- 1:17:08so you We're not mathematicians. When we
- 1:17:10if we were, we'd be terrible
- 1:17:11mathematicians. So, we're we're trying
- 1:17:13to explain the world and if the world
- 1:17:15keeps saying this isn't fitting, you
- 1:17:16just got to throw it out. You got to
- 1:17:18live with it. But I think you said
- 1:17:20something else too, which is kind of a
- 1:17:21like a I think another issue, which is
- 1:17:23that if you really doubt the the
- 1:17:26veracity of the data, and in some
- 1:17:28context you are going to doubt it, then
- 1:17:30maybe that's not the right metric you
- 1:17:32should be using for your model. So, you
- 1:17:34might say, look, you know, my model's
- 1:17:36not fitting. Um, I think it's what's
- 1:17:39going on and I have these other maybe
- 1:17:41stylized facts that make me think this
- 1:17:43is actually really true and important.
- 1:17:44The data is is rejecting it, but I have
- 1:17:47reasons to believe [snorts] that that
- 1:17:49data is incorrect. So, so then you're
- 1:17:53questioning the data, right? You're
- 1:17:55questioning then what are you
- 1:17:56questioning then? You're you're
- 1:17:57questioning our our empirical picture,
- 1:17:59our picture of, you know, the the
- 1:18:01reality. Now, that's a different issue.
- 1:18:04Like if if you have deep reasons and
- 1:18:06good reasons to to doubt the the
- 1:18:09veracity of the picture you're getting
- 1:18:10from the data then you shouldn't be
- 1:18:12trying to match that data. So so I think
- 1:18:15I think but but what would what I would
- 1:18:17resist you know exant is just building a
- 1:18:21model it doesn't fit the data and then
- 1:18:24saying oh that's because you know now I
- 1:18:25want to say the data is bad. So you have
- 1:18:27to be careful right? So because you can
- 1:18:28always just say look I'm not going to
- 1:18:30you know that thing that I'm seeing
- 1:18:32outside the window that didn't happen
- 1:18:34right and you know so you have to resist
- 1:18:36that. So but yeah um some data is very
- 1:18:40reliable right so that's the ones and
- 1:18:42some some isn't and then you know you're
- 1:18:44right you got a problem and you know
- 1:18:45this is we don't usually go there in
- 1:18:47economics too much right so we usually
- 1:18:49but you know there's a there's a kind of
- 1:18:50a more profound critique which is like
- 1:18:52the post structural postmodern critiques
- 1:18:55which is that all data is generated all
- 1:18:57data is you know they put a lot of they
- 1:18:59think we're very naive in the way that
- 1:19:01we view the world and and partly that
- 1:19:03there's a truth to that like a lot of
- 1:19:04this is a postcolonial literature
- 1:19:06saying, you know, the data was created
- 1:19:08by the victors and tells a narrative and
- 1:19:11that narrative is one that's in the
- 1:19:13favor of a particular class of people or
- 1:19:15something like that. So, we don't
- 1:19:17usually do those post post type uh
- 1:19:20critiques in economics, but I think
- 1:19:22there's a there's something to that and
- 1:19:24in some context there really is
- 1:19:25something to that. So, you know,
- 1:19:26sometimes the data can be dodgy. Yeah.
- 1:19:30>> Thank you, sir.
- 1:19:32>> You're welcome.
- 1:19:33>> Thank you, Carass. Um, we'll go back now
- 1:19:36to the chat and there there are a couple
- 1:19:38questions about counterfactuals.
- 1:19:41Um, I'll read one. It says, "In
- 1:19:43structural political economy, how do you
- 1:19:45prevent overspecifying candidate
- 1:19:47mechanisms when structural
- 1:19:48counterfactuals heavily depend on
- 1:19:50institutional primitives that remain
- 1:19:52unobservable or underidentified in
- 1:19:54baseline empirical facts?"
- 1:19:56>> Yeah, that's a good question. Yeah. So,
- 1:19:58um, so, so I think there's two things
- 1:20:00here. So one is um
- 1:20:04yeah when they're unobservable you know
- 1:20:07we're really in the realm of you know
- 1:20:08you have to try to convince people that
- 1:20:10you know when when I'm doing this
- 1:20:11counterfactual that those primitives are
- 1:20:13not going to change and you know how do
- 1:20:15you do that um
- 1:20:18various ways I mean you could maybe
- 1:20:20point to other contexts where they were
- 1:20:22relatively invariant across such a
- 1:20:24change that would be one way to do it
- 1:20:25but you know it's not always going to be
- 1:20:26available so there may be ways of
- 1:20:29convincing people by pointing to
- 1:20:30analogist situations
- 1:20:33often there isn't and then it's just
- 1:20:34going to come down to people you know I
- 1:20:37you see it and people are often too
- 1:20:38polite to say in the seminar but they're
- 1:20:40like uh you know come on like you know
- 1:20:42under that counterfactual everything
- 1:20:44everything would change it's like you
- 1:20:46can't hold x fixed you know whatever it
- 1:20:49is whatever the parameters fixed theta
- 1:20:52so you know that it's just it's just
- 1:20:54it's there's no kind of clear formula
- 1:20:56for that you know it's in a sense we're
- 1:20:57trying to it's we're running narratives
- 1:20:59and we're trying to convince convince
- 1:21:00others that this is a sensible thing to
- 1:21:01do. [sighs]
- 1:21:03Um the question of overfitting I think
- 1:21:06is a slightly different one in the sense
- 1:21:08that you know uh when you're I mean I
- 1:21:12think this is one of the advantages of
- 1:21:13of doing structural work is when you
- 1:21:16have a a a structural framework you
- 1:21:20actually have your model you have your
- 1:21:23set of parameters you have your
- 1:21:24estimates and you fit the data however
- 1:21:28you fit it. Now you know I I know I can
- 1:21:32always write down a model with more
- 1:21:33parameters, more moving parts that will
- 1:21:35fit better. I know I can do that. Now
- 1:21:40how do you compete? How do you test
- 1:21:42between those models? So there are tests
- 1:21:43that actually do penalize overfitting.
- 1:21:46So we can formally do that. So that's
- 1:21:49that's uh
- 1:21:51one way one way that we do it. Now it
- 1:21:54depends on your context, right?
- 1:21:55sometimes just fitting is what you want
- 1:21:57to do and then you don't even care about
- 1:21:59the economic narrative right so if
- 1:22:01you're you know LLM are essentially
- 1:22:03doing that they have you know a
- 1:22:04gazillion which is where gazillion is a
- 1:22:06large number of parameters that they
- 1:22:08estimate on a on a on a on a very big
- 1:22:10data set and it allows them to predict
- 1:22:13now do we understand no we don't
- 1:22:15understand how it's doing it I it's
- 1:22:17totally a mystery how they can provide
- 1:22:19such coherent answers to things but it
- 1:22:21is just a big structural estimation
- 1:22:24problem on a lot of data and that in
- 1:22:27that context that's the right thing to
- 1:22:29do right in economics context we don't
- 1:22:31usually want that what we want is to
- 1:22:34provide a narrative an explanation for
- 1:22:36the observables and generally we want to
- 1:22:40not have a blackbox explanation so so
- 1:22:43but but in the set of explanations that
- 1:22:45are not blackbox we can have two that
- 1:22:47would rationalize you know not
- 1:22:49rationalize in in a structural setting
- 1:22:50we're matching we're fitting the data
- 1:22:52the one with more parameters will often
- 1:22:53fit better, but you know, it's coming at
- 1:22:55the cost of more parameters and we have
- 1:22:56tests to to trade these off. So, I think
- 1:22:58it's a combination of this story is a
- 1:23:00good story. It fits the data pretty
- 1:23:03well. It explains things pretty well. It
- 1:23:04doesn't seem like it's overfitted. You
- 1:23:06know, it's kind of more of a handwavy
- 1:23:08type thing, you know. Um, yeah,
- 1:23:12elements of science, elements of art
- 1:23:14there,
- 1:23:15>> art and science together.
- 1:23:17>> Um,
- 1:23:18>> Zoo, uh, over to you. Do you want to ask
- 1:23:21your question?
- 1:23:22>> Yeah. Uh can you hear me? Um thank you
- 1:23:25uh Professor Francois. Uh kind of a big
- 1:23:27picture question. Uh where do you see
- 1:23:29the role of applied political economy
- 1:23:32modeling in development and political
- 1:23:34economy in the future given that there
- 1:23:36was a trend in development economics
- 1:23:38credibility revolution that there's a
- 1:23:40lot of kind of replete with empirical
- 1:23:42facts and a lot of improvement in
- 1:23:45identification of those empirical facts.
- 1:23:46Do you see the same trend that um we're
- 1:23:50moving towards you know identifying
- 1:23:52mechanisms to applied modeling and uh
- 1:23:55second part of that is what advice
- 1:23:57particular advice would you give to kind
- 1:24:00of young researchers who try to navigate
- 1:24:02that landscape?
- 1:24:04>> Yeah, it's tough. So, so I think I I you
- 1:24:07know I think so I I primarily see myself
- 1:24:10as a development economist. That's what
- 1:24:12I'm interested in. That's what I've
- 1:24:14always liked. And I moved into political
- 1:24:16economy um because I felt like the
- 1:24:19questions that I wanted to understand
- 1:24:21weren't really being tackled in in
- 1:24:23development. And partly it's because um
- 1:24:26it became so a theoretical. I was always
- 1:24:29interested in mechanisms like why is
- 1:24:30there so much variation in development?
- 1:24:32Why do we see these big differences? And
- 1:24:34the questions that they're very hard to
- 1:24:37to answer because it's very hard to
- 1:24:39identify a particular mechanism. So you
- 1:24:42never fully identify things very well
- 1:24:44unless you can actually control the
- 1:24:45variation. So I think development got
- 1:24:48very obsessed with and in a good way,
- 1:24:50right? It got obsessed with trying to
- 1:24:53say things that were true, trying to
- 1:24:55identify causal relationships. That was
- 1:24:58a good thing because again, when I was
- 1:25:00in grad school, people were just
- 1:25:02regressing indogenous things on each
- 1:25:03other all the time and it was very
- 1:25:05sloppy. So it needed it, right? Um,
- 1:25:09but I feel like to me that's a kind of
- 1:25:11a,
- 1:25:13you know, I mean, I think it's it's not
- 1:25:15unreasonable for people to say, why
- 1:25:17isn't anyone doing development anymore?
- 1:25:19Like, why isn't anyone asking the big
- 1:25:20questions? Why is everyone just finding
- 1:25:22out very specific bits of information
- 1:25:24about things that will work in
- 1:25:26particular contexts? And and I think
- 1:25:29that, yeah, that's a reasonable
- 1:25:30question. So, I I I don't I'm not very
- 1:25:32good at predicting the future. I I don't
- 1:25:34think political economy is going to go
- 1:25:36there. I think the best to me the best
- 1:25:39case scenario is people are asking
- 1:25:41questions that are big thinking about
- 1:25:44with theory usually because it's just
- 1:25:46too hard to do without it. Thinking
- 1:25:48about like the the things I should be
- 1:25:49able to run in my experiments that will
- 1:25:51help me identify those bigger questions.
- 1:25:54So so it's a combination of both. I
- 1:25:56don't I see and so to answer your
- 1:25:58question I think for a student I think
- 1:26:01we teach people how to solve complicated
- 1:26:04models very well in grad school we do
- 1:26:06complicate and we actually select for
- 1:26:08math mathiness in that sense but I don't
- 1:26:11think we teach people very well how to
- 1:26:13build models and I feel like there's a
- 1:26:17lot of value added to doing a little bit
- 1:26:19of that model building in the empirical
- 1:26:22project. So as a grad student, I would
- 1:26:24invest a bit of time in that which is in
- 1:26:26the political economy realm. To me, it's
- 1:26:27understanding those canonical models,
- 1:26:29having them in the back of my mind.
- 1:26:30That's the advice I would that's the
- 1:26:32advice I do give and I I would give and
- 1:26:34I teach this course. I teach like a
- 1:26:3612-week course on how to build models in
- 1:26:38political economy. That's what I do
- 1:26:39because I think it's a useful thing.
- 1:26:40It's a complement to your core and it's
- 1:26:43still your core business which is the
- 1:26:44empirical one.
- 1:26:48>> Thank you very much, professor.
- 1:26:50>> Yeah, no worries. Thank you. It is
- 1:26:52pretty incredible um just everyone
- 1:26:54that's here how condensed
- 1:26:58uh the professors are making what is
- 1:27:02normally maybe a semester long class
- 1:27:04into an hour hour and a half uh every
- 1:27:08week. And so um we we recognize there is
- 1:27:11a lot of of information but it's
- 1:27:15something that you'll be able to
- 1:27:16reference back to and and build on. Um,
- 1:27:20I think that this is really the that's
- 1:27:22kind of the zoomed out perfect place to
- 1:27:24to end the lecture. And I just really
- 1:27:27want to thank Professor Vansis for your
- 1:27:30time and um your your insights.
- 1:27:34Everyone, I've I've put in just a couple
- 1:27:37of things into the chat um for links
- 1:27:40that that you should reference, but but
- 1:27:42really thank you for coming. Uh we we
- 1:27:45look forward to to you joining us next
- 1:27:48week with Professor Tim Bezley u to talk
- 1:27:52about state capacity and we uh look
- 1:27:55forward to seeing you then.
- 1:27:56>> Thank thank you too for um letting me do
- 1:27:59this and I I enjoyed it a lot. I think
- 1:28:01the questions were great and I think
- 1:28:03this is a really good initiative too
- 1:28:04just to get a a view of how all of us
- 1:28:07approach this a little bit differently
- 1:28:09and you should definitely go to Tim's
- 1:28:10talk. Tim is one of the great applied
- 1:28:13modelers, right? So, he is does exactly
- 1:28:16this, I think. Um, and he also, you
- 1:28:18know, he's just great. So, you should
- 1:28:20come to it and enjoy it. You'll learn a
- 1:28:22lot.
- 1:28:23>> Well, we have a personal endorsement
- 1:28:25here, guys. So, so we'll very much uh
- 1:28:28hope to see you next week. Thank you
- 1:28:29again, Patrick, and hope everyone has a
- 1:28:31great rest of your days.
- 1:28:32>> Thank and thank you, Caleb. You did a
- 1:28:34great job.
- 1:28:35>> Thank you.
- 1:28:36>> Was excellent lecture. Thank you.
- 1:28:38>> Thank you.
- 1:28:38>> Thank you. Thank you.
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