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BREAD-IGC virtual PhD-level course 2026 | Lecture 3 Core Political Economy Models — Transcript

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  1. 0:34All right, welcome everyone uh back to
  2. 0:37the Brad IGC
  3. 0:40Bred uh PhD level course on political
  4. 0:43economy. We are here for our third
  5. 0:45lecture. We're very grateful to have Pat
  6. 0:47Patrick Francois with us. He's a
  7. 0:50professor at the University of British
  8. 0:52Columbia and teaches in the Vancouver
  9. 0:54School of Economics.
  10. 0:56And before I pass over to him, I just
  11. 0:58want to go over our kind of standard
  12. 1:01housekeeping items. Um, I will put this
  13. 1:03in the chat as well, but all the reading
  14. 1:07lists, slides, and past recordings are
  15. 1:11available on our website. I'll put that
  16. 1:13link in. And so, if you have questions
  17. 1:16around you missed a week or or the
  18. 1:19reading list for next week, just check
  19. 1:22um that location. The second thing is
  20. 1:26for attendance
  21. 1:28that is captured automatically by Zoom.
  22. 1:30So you don't need to send in any
  23. 1:32personal note or email saying that that
  24. 1:35you were here. And there is a a bar of
  25. 1:4010 uh 10 kind of lectures attended for
  26. 1:44the cert certification
  27. 1:47um at the end of the course. this being
  28. 1:50the third, the this will if you if
  29. 1:53you're just joining this week and you
  30. 1:55attend the next uh this one and the next
  31. 1:58nine, then you'll still be able to get
  32. 1:59that that certificate.
  33. 2:01Um now, if anyone would like to kind of
  34. 2:04be a live participant here and have
  35. 2:06their video on uh to be in kind of the
  36. 2:10virtual classroom, please raise your
  37. 2:11hand now and I'll randomly select 15 or
  38. 2:1320 of you. uh please still keep your mic
  39. 2:17muted but your video on and then during
  40. 2:19the Q&A session you'll be able to
  41. 2:21interact and ask um questions. For
  42. 2:23others that have questions just put them
  43. 2:25into the Q&A box and we'll try to answer
  44. 2:28those throughout.
  45. 2:30Okay, I think that's everything from me.
  46. 2:32So I'll pass it over to Patrick to kind
  47. 2:35of go over um everything that we need to
  48. 2:38know about core political economy
  49. 2:39models.
  50. 2:42Okay, thanks [clears throat] Caleb and
  51. 2:45thanks to IGC and Brad and CPR for
  52. 2:48having me for this uh this lecture.
  53. 2:50Okay, so uh yeah, I'm not going to teach
  54. 2:53you everything you need to know about
  55. 2:54political economy models. There's a lot
  56. 2:56more that I'm that I'm going to miss
  57. 2:57that I'm going to cover, I'd say. Um
  58. 3:02uh okay, so I can't see the top of that,
  59. 3:05but I guess you can. So yeah, there we
  60. 3:07go. So, um,
  61. 3:10what's this, uh, lecture going to be
  62. 3:12about? It's going to be back to thinking
  63. 3:15about, uh,
  64. 3:19what we do with models. Okay? So, I'm
  65. 3:21not going to survey political economy
  66. 3:23models. I I want you to take away from
  67. 3:26this lecture answers to the following
  68. 3:29questions. what models are for, how
  69. 3:33modeling actually begins, applied
  70. 3:34modeling, how a canonical model becomes
  71. 3:36useful for you, and I'm going to talk
  72. 3:38about a few of the canonical models at a
  73. 3:40very high level, how model adds value to
  74. 3:43data, and where you must exercise
  75. 3:45judgment.
  76. 3:47Okay? So my aim is for you to see econom
  77. 3:50data in a model first way. Okay? So in
  78. 3:54order to do that, I want you to think
  79. 3:56back to undergraduate economics. Okay.
  80. 3:59So, when you first started taking
  81. 4:02economics and I think you probably all
  82. 4:04did what I did, you start with thinking
  83. 4:07about markets and
  84. 4:10the actual observables you have in
  85. 4:12markets are essentially quantities and
  86. 4:14prices. That's what we see in markets.
  87. 4:17Yet, that's not really what we deal
  88. 4:20with. What we first do is we make up
  89. 4:22this abstraction
  90. 4:24which is the idea of supply and demand
  91. 4:26which are fictions. right? We we make up
  92. 4:29a supply curve, a demand curve. We think
  93. 4:31about them when we go a little bit
  94. 4:33further. We think about like the
  95. 4:34underpinnings of that things like
  96. 4:36consumer choice and the behavior of the
  97. 4:38firm. Um and then we kind of go a little
  98. 4:40bit further and we think about
  99. 4:41monopolies and things like
  100. 4:42externalities.
  101. 4:44So
  102. 4:46when we're thinking about the actual
  103. 4:48observables, quantities and prices,
  104. 4:50we're not basically doing this a
  105. 4:52theoretical thing, which is to say,
  106. 4:54well, you know, a natural question would
  107. 4:55be to ask how are these things
  108. 4:56correlated? How do quantities and prices
  109. 4:59move together? And that's not a sensible
  110. 5:02question. That's actually a question
  111. 5:05that if you did that, you'd find all
  112. 5:06sorts of weird correlations between
  113. 5:08quantities and prices depending on which
  114. 5:10curve was moving in the background,
  115. 5:11supply or demand. So our our way of
  116. 5:14thinking about it is really structured
  117. 5:16by the fiction that really drives our
  118. 5:19empirical approach to them.
  119. 5:21And I want to argue to you that this is
  120. 5:24how we as economists think implicitly
  121. 5:26for the rest of our careers. We're
  122. 5:28really conditioned by that way of
  123. 5:30thinking and it's a good thing and
  124. 5:34we should do that in the political
  125. 5:37economy realm as well. Okay. So what do
  126. 5:39these simple models actually teach us?
  127. 5:42They teach us the same things that we
  128. 5:44learn essentially in the supply and
  129. 5:46demand world. So in the in the supply
  130. 5:49and demand mode just remind you what are
  131. 5:50those things in a market we ask what
  132. 5:51shifted demand what shifted supply and
  133. 5:53remember these are fictions right
  134. 5:54they're not the real things we observe
  135. 5:56what shifted those things which margin
  136. 5:58moved what's the equilibrium response
  137. 6:01what happens if we were to do something
  138. 6:02like intervene so that the model becomes
  139. 6:06so ingrained in our thinking about this
  140. 6:10context that it actually becomes the
  141. 6:11language of our conceptions in our mind
  142. 6:16deeply
  143. 6:18So I'm going to argue the political
  144. 6:20economy thinking about political economy
  145. 6:21as grad students or as advanced
  146. 6:23economists needs the same kind of
  147. 6:25language. So um a small number of
  148. 6:28strategic problems happen again and
  149. 6:30again in political economy contexts.
  150. 6:33Okay. So just to list them I mean this
  151. 6:35is my kind of uh thinking about it and
  152. 6:38I'm sure there are others that uh I
  153. 6:40don't think about too much but here are
  154. 6:41the ones that are important for me.
  155. 6:42Politicians competing for voters. Voters
  156. 6:45disciplining politicians. Citizens
  157. 6:47deciding whether to become politicians
  158. 6:49themselves. Politicians bargaining over
  159. 6:52how to divide things up. Usually the big
  160. 6:54thing is power. Groups expending
  161. 6:57resources to actually control political
  162. 6:59office. The credibility of promises made
  163. 7:03by politicians. Citizens trying to
  164. 7:06coordinate punishments and to discipline
  165. 7:08politicians and information asymmetries
  166. 7:12that arise between the informed actors.
  167. 7:14usually the political agents and and and
  168. 7:17the principles who are the voters.
  169. 7:19So I'm going to argue that these are the
  170. 7:21political economy equivalents of supply
  171. 7:22and demand.
  172. 7:25Okay. So we can I I I put these readings
  173. 7:30on the reading list. They're by no means
  174. 7:32essential, but these are the ones that
  175. 7:34for me are the canonical models that
  176. 7:38provide a a sort of a conceptual way of
  177. 7:41thinking about these problems. So the
  178. 7:43Dian models for politicians competing
  179. 7:46for voters. The fair John and Fieran
  180. 7:48paper um in in the issue of voters
  181. 7:52disciplining politicians citizens entry
  182. 7:55into polit political office is the
  183. 7:57Osborne Slovinsky and Basian co-papers
  184. 8:00politics and bargaining overpowered
  185. 8:01Baron Fjon and on and on. So here
  186. 8:04they're listed. I'm going to list them
  187. 8:05again later. I'm not going to go through
  188. 8:07any of these models in any detail.
  189. 8:10I think it's not that useful to do it in
  190. 8:12a short period of time, but just so you
  191. 8:14have them, these are the ones that I go
  192. 8:16to first. They come into my mind when I
  193. 8:18think about these particular situations.
  194. 8:21Okay. So, what's the point of them? The
  195. 8:24point of reading these, I think, is
  196. 8:25great. They're great papers. They're
  197. 8:26famous papers for the most part, but you
  198. 8:29don't need to remember anything about
  199. 8:30them. They're useful. Why? because they
  200. 8:35have a sort of a strategic structure and
  201. 8:37architecture
  202. 8:39which when you learn to recognize them
  203. 8:42you can
  204. 8:44see and think about how to apply them in
  205. 8:46empirical settings. So once you
  206. 8:47recognize them you see this that this
  207. 8:50structure sort of pops up in a lot of
  208. 8:51empirical contexts and it can motivate
  209. 8:53your your way of thinking about the
  210. 8:56data.
  211. 8:58So applied modeling usually does start
  212. 9:00with data and this is a sense in which
  213. 9:02as graduate students you will usually
  214. 9:05come at a problem with data first and
  215. 9:08that's a good thing. So I think this is
  216. 9:10very different than and what I want to
  217. 9:12talk about today is very different than
  218. 9:13being a theorist. You know I'm not a
  219. 9:15theorist. I'm I'm an applied theorist. I
  220. 9:17I look at data. I usually work with
  221. 9:21empirical people or I do some rud
  222. 9:23rudimentary empirical work myself and
  223. 9:25then I think about how to structure it
  224. 9:27using models.
  225. 9:28Okay. So, so it starts with data and I
  226. 9:30think this is a great this is where we
  227. 9:32should start. We should be disciplined
  228. 9:33by data and suppose that you have built
  229. 9:35a data set from something, right? So, it
  230. 9:37could be a a an RCT could be you have
  231. 9:40access to administrative data. You've
  232. 9:42come to the archives and you've created
  233. 9:44one surveys, census, web scraping, which
  234. 9:47is incredibly common and cheap and
  235. 9:49relatively easy to do now or just obser
  236. 9:52ordinary observational data.
  237. 9:54Okay? So you do that work, you do it
  238. 9:57carefully and you might even find
  239. 9:59something interesting. So you find some
  240. 10:00interesting correlations or even some
  241. 10:02interesting causal relations.
  242. 10:04So so what often happens is the data is
  243. 10:07telling you something, right? So
  244. 10:08something like this. X goes up and Y
  245. 10:10then goes up. Okay? And maybe you've
  246. 10:13established it well. You've even got a a
  247. 10:14clear causal relationship. It's X going
  248. 10:16up that makes Y go up. Okay? So you can
  249. 10:20write a paper just showing that. And for
  250. 10:22some data, for some variables, that's
  251. 10:26actually super important just to
  252. 10:28establish a causal relation like that.
  253. 10:30And usually that's going to be important
  254. 10:33as a standalone fact on its own. Once
  255. 10:36theory and once the profession is
  256. 10:38decided, we need to know that
  257. 10:39relationship. So once that's already
  258. 10:41decided, then just establishing it
  259. 10:44empirically can itself be an important
  260. 10:46contribution. But that's not usually the
  261. 10:49case for students doing PhDs. They don't
  262. 10:52usually happen upon the key empirical
  263. 10:56finding that's just going to resolve a
  264. 10:57bunch of theoretical or or open
  265. 11:00conjectures in in economics. That's not
  266. 11:02usually what happens. What usually
  267. 11:03happens is you just found a correlation
  268. 11:04in some data. Now, when it becomes when
  269. 11:08you can elevate that to something that's
  270. 11:10a more significant contribution is when
  271. 11:12you can answer a different question,
  272. 11:14which is the why question. And that's
  273. 11:16the modeling question. Why is this
  274. 11:18happening?
  275. 11:20So the implied modeling sequence is
  276. 11:22inserting the modeling thinking into
  277. 11:26that data collection process. So this is
  278. 11:29where it fits. You have data, you
  279. 11:32establish an empirical fact like X goes
  280. 11:35up then Y follows. Then you think about
  281. 11:37a mechanism and a mechanism is just a
  282. 11:40story, a narrative, a parable, whatever
  283. 11:43you want to put it, but it's just what's
  284. 11:45going on here. Then you formalize it,
  285. 11:47okay, with a model. And that's because
  286. 11:50means a few reasons why we want to
  287. 11:51formalize it. We'll get into that in in
  288. 11:53a little bit, but in a nutshell, it's
  289. 11:55because telling the story often doesn't
  290. 11:57do the full idea justice. It's hard to
  291. 12:00tell whether it all hangs together. And
  292. 12:02a model helps you know whether it hangs
  293. 12:04together. But it does much more. One of
  294. 12:05the things that actually can and should
  295. 12:08do, I'd argue, is provide new
  296. 12:10predictions. Then it tells you where to
  297. 12:12go and get new evidence. Often there's a
  298. 12:14back and forth between data, theory, and
  299. 12:17data. So the model sits inside, it's
  300. 12:19embedded in this what I call empirical
  301. 12:21research process.
  302. 12:23So step one is often very simple and
  303. 12:25modest. And what is that step one?
  304. 12:28First, it has to explain the thing you
  305. 12:29found. That's the point of building the
  306. 12:31model, right? If the data says A goes
  307. 12:34up, then B goes up and C equals 1
  308. 12:37implies B goes down, then your mechanism
  309. 12:40should be able to generate both of those
  310. 12:42things. So you have to think about a
  311. 12:43story. If it can't do that, if the story
  312. 12:45can't explain the basic observations you
  313. 12:48have, it's failed at step one. So that's
  314. 12:50where you exist in the first instance.
  315. 12:53You have to try to use the model, your
  316. 12:55thinking, your story to explain what
  317. 12:57you're observing. Okay? But the problem
  318. 13:00is it's not a problem, but the fact is
  319. 13:03uh that's pretty easy to do in a lot of
  320. 13:05context, right? Rationalization is
  321. 13:07cheap. And that's just why because we're
  322. 13:10good at telling stories. Like this is
  323. 13:11just part of what humans do. We're great
  324. 13:14at it, right? So we can tell any sort of
  325. 13:16BS story. BS meaning not true and with
  326. 13:19enough assumptions you can almost
  327. 13:21rationalize any fact. So some of these
  328. 13:23stories are not very interesting but
  329. 13:25they may be true. So reducing so just
  330. 13:28making the story fit the correlation
  331. 13:30that's the point of it but that's
  332. 13:32obviously not sufficient. Okay. So then
  333. 13:34the question is what what would make it
  334. 13:36sufficient? And this what would make it
  335. 13:38sufficient is when the model's starting
  336. 13:40to provide some discipline beyond the
  337. 13:42initial story that you came up with. So
  338. 13:44what I mean a m a useful model should do
  339. 13:46this. It should tell you some of these
  340. 13:48things. So one of them is it should tell
  341. 13:50you when the result holds. So x going up
  342. 13:53implies y going up. That's the data. But
  343. 13:56maybe the model tells you and this is
  344. 13:59embedded into your structure is that
  345. 14:03well that's only if some parameter alpha
  346. 14:05is greater than alpha bar. Why is that
  347. 14:07useful? Well, firstly, it's it's may
  348. 14:10just be a a consequence of something
  349. 14:13that's totally arbitrary like the
  350. 14:14functional form assumption. If it's
  351. 14:16that, then it's not useful. But if it's
  352. 14:18profoundly part of the story, that in a
  353. 14:20sense that you can't write down a
  354. 14:22functional form that wouldn't make it
  355. 14:23true. It actually depends on this
  356. 14:25parameter alpha being high enough, then
  357. 14:28that's giving you a new empirical
  358. 14:31question, right? It's saying where in
  359. 14:33the data should this hold? Is there a is
  360. 14:35there something that corresponds to
  361. 14:36alpha in the data? If it's doing that
  362. 14:38then it's already giving us more than
  363. 14:40just a rationalization.
  364. 14:42It should generate some sort of
  365. 14:43heterogeneity. Right? So suppose like I
  366. 14:46said y goes x goes up y goes up
  367. 14:51then we should also have something else
  368. 14:54like this that well that depends on zed
  369. 14:57as well. So if you see an interaction
  370. 14:59term like that second derivative is also
  371. 15:02positive. The model says the effect
  372. 15:03should be stronger where zed is high.
  373. 15:05Maybe nobody looked at that. Maybe you
  374. 15:07didn't think about that before the model
  375. 15:09existed. If that's the case, again, it's
  376. 15:10a useful model.
  377. 15:13It should generate some auxiliary
  378. 15:15predictions. These are auxiliary. But
  379. 15:16here's some more. The motivating factor
  380. 15:18is X goes up, Y goes up. Also, the
  381. 15:19mechanism should also imply if X goes
  382. 15:21up, maybe W goes down. Often W wasn't
  383. 15:24even thought of when you were getting
  384. 15:26the data when you were initing the facts
  385. 15:28or when you were constructing the model.
  386. 15:30and and in that case it's it's likely
  387. 15:32that the prediction is super
  388. 15:33informative. It's again telling you
  389. 15:35somewhere else to look empirically. So
  390. 15:37the model here is a tool and it's a tool
  391. 15:40because we're not smart enough to do all
  392. 15:41this abstractly in our head or in or in
  393. 15:43narrative or in English. Putting it in
  394. 15:45math allows us to get insights that we
  395. 15:48couldn't get otherwise.
  396. 15:51So um let's just take an example of
  397. 15:54that. So this is all that's all abstract
  398. 15:56in terms of x's and y's and ws. suppose
  399. 15:57the motive fact is this that you know
  400. 15:59coastal constituencies so if you get you
  401. 16:02know little electorates or little um
  402. 16:04political contests that are near the
  403. 16:05coast tend to have more corruption I
  404. 16:08don't know if this is a fact I'm just
  405. 16:09making it up so let's just think about a
  406. 16:11story so one one possible mechanism is
  407. 16:13there's reduced spatial competition
  408. 16:15right so when constituents or businesses
  409. 16:18uh have fewer substitutes nearby because
  410. 16:20one side is bounded by the sea there's
  411. 16:22less discipline on political bad actors
  412. 16:25there's there's less latitude but less
  413. 16:26places fewer places to go. So then the
  414. 16:29model should also predict what that
  415. 16:30lakefront constituencies should have
  416. 16:33more corruption because they have the
  417. 16:34same issue. So lakes were never part of
  418. 16:37the facts used to motivate the model
  419. 16:38that the model was about data which was
  420. 16:41about the coast versus the inland.
  421. 16:45This story would tell you look if that's
  422. 16:47the right thing then it should be true
  423. 16:48in lakes too and in big lakes.
  424. 16:52So that comes from the mechanism and
  425. 16:54it's not just mechanically extending the
  426. 16:56correlation. You could just mechanically
  427. 16:57extend it by saying, "Well, it's just
  428. 16:59water and there's water there." That's
  429. 17:00not it. It's about this spatial
  430. 17:02component.
  431. 17:05Okay? So, sometimes the models are going
  432. 17:07to actually tell you what data to
  433. 17:08collect. So, I can point to another
  434. 17:10variable, another question, something
  435. 17:12about beliefs. You should ask people
  436. 17:14about their beliefs, information,
  437. 17:15another treatment. So, this arrow from
  438. 17:18data to thinking about the model, then
  439. 17:20to new data, that's great if that
  440. 17:23happens. And sometimes as I said earlier
  441. 17:28actually usually lots of mechanisms are
  442. 17:30going to fit the same fact. So you know
  443. 17:32you might have model A B and C that can
  444. 17:34all generate when X goes up Y goes up.
  445. 17:37That's normal.
  446. 17:40When these models become valuable is
  447. 17:42when they start generating differences.
  448. 17:44So if they're exactly equivalent then
  449. 17:47we've got no way of telling between
  450. 17:49them. But that's rarely the case. Right?
  451. 17:52So when they diverge then they start
  452. 17:56providing possibilities for
  453. 17:58distinguishing between them.
  454. 18:01So
  455. 18:02the model then becomes a machine that
  456. 18:06you can use to design your data
  457. 18:07collection moving forward. So what
  458. 18:10comparative statics differ across the
  459. 18:11models? Which subgroups differ? What
  460. 18:14treatments would distinguish the
  461. 18:16mechanisms? What observables would move
  462. 18:19them in different directions? and what
  463. 18:21new data should you collect? So theory
  464. 18:24can tell the empiricists what to do
  465. 18:25next. So we should all as empiricists,
  466. 18:28we should all also be theorists in this
  467. 18:30sense. So it's particularly useful if
  468. 18:32done prior to going to the field or
  469. 18:35after piloting after you've been to the
  470. 18:36field and got a sense of what's going
  471. 18:38on. You might have some prior about the
  472. 18:40variables you should think about. When
  473. 18:42you see the piloting, when you go to the
  474. 18:45field, when you speak to people, you're
  475. 18:46like, you know, these are not the big
  476. 18:47moving parts. I should think about
  477. 18:49something else. I have a mechanism in
  478. 18:50mind. It tells me other things that I
  479. 18:53should ask.
  480. 18:55So I'm going to provide an illustration.
  481. 18:57I think this is a great model. I I put
  482. 19:00it as an a reading to do. Uh it's a it's
  483. 19:03a paper from Gerard Padre Miguel in
  484. 19:06Review of Economic Studies and it
  485. 19:08basically asks the question and it's a
  486. 19:10pure theoretical paper. Okay. Why do
  487. 19:12citizens continue to support leaders who
  488. 19:15are basically stealing from them or
  489. 19:18governing terribly? So
  490. 19:21usually and he starts from this position
  491. 19:23that this is got something to do with
  492. 19:25identity. People tend to support people
  493. 19:26who are from the same identity group. So
  494. 19:28it happens in in societies that are
  495. 19:30polarized or clustered around identity
  496. 19:33markers like for instance tribal
  497. 19:35markers. So he notes that a tempting
  498. 19:38explanation I don't think he actually
  499. 19:40notes this but I think a tempting
  500. 19:41explanation is just say look we've got a
  501. 19:43taste for supporting somebody from our
  502. 19:45own group. We just have an inherent
  503. 19:46tendency to want to support people vote
  504. 19:49for people who are like us
  505. 19:50linguistically culturally physically you
  506. 19:54could just say this is like a
  507. 19:56psychological tendency. Okay. So he
  508. 20:00takes I think a much more deep economic
  509. 20:03approach. She says look this can emerge
  510. 20:04from an interaction that we don't have
  511. 20:06to posit that as a feature of our
  512. 20:09preferences. This can be an equilibrium
  513. 20:11outcome.
  514. 20:13Okay. So here's the core mechanism. So
  515. 20:15if you've read the paper you'll be
  516. 20:16familiar with the notation here. This is
  517. 20:20sort of a a slightly bastardized version
  518. 20:21of his notation. But I think the
  519. 20:24interesting thing is that um that his
  520. 20:26his uh his his his
  521. 20:29theoretical approach is you know a a
  522. 20:32beautiful elegant way of generating the
  523. 20:35story as an emergence rather than a
  524. 20:37direct assumption. Okay. So suppose the
  525. 20:39following is true. He he makes his
  526. 20:41assumption. Suppose if you keep the
  527. 20:43incumbent the probability that you're
  528. 20:44going to hold on to power is greater. So
  529. 20:47he calls this gamma overbar and I'm
  530. 20:50going to call it for a for group A.
  531. 20:52That's the probability you'll stay in
  532. 20:54power if you keep your incumbent in
  533. 20:55power. If you remove your incumbent,
  534. 20:57that probability is lower. Some gamma
  535. 20:59underbar a and suppose I value holding
  536. 21:02power. So that means the value to me as
  537. 21:05an a person if I have an a leader is
  538. 21:07bigger than the value if I have a b
  539. 21:09leader. Okay.
  540. 21:12So he notes and he generates this as an
  541. 21:15equilibrium object that supporters may
  542. 21:19accept a loss as large as this amount.
  543. 21:22Okay. And this is a kind of a political
  544. 21:24slack. And the story is very simple. If
  545. 21:28I were [snorts] to remove my current
  546. 21:30politician then I will have suffer this
  547. 21:33decline in the probability of holding
  548. 21:36power. How much do I value holding
  549. 21:38power? This much. So that's the actual
  550. 21:42amount that I fear losing
  551. 21:45and delta is a discount rate.
  552. 21:49This is a type of a rent that the
  553. 21:52politician
  554. 21:53can exploit. They can do things up to
  555. 21:56this. They can steal up to this. They
  556. 21:58can be slack up to this. It's a
  557. 22:00political rent. That e kleptocratic rent
  558. 22:03that he calls it. So the more I fear the
  559. 22:05other group taking power, the more badly
  560. 22:07my own leader can treat me. Why is this?
  561. 22:09Well, the worse it would be for me if
  562. 22:11the other group takes power, the bigger
  563. 22:13this rent is. So, this is his mechanism
  564. 22:17for explaining why people will be in an
  565. 22:21equilibrium where they continually
  566. 22:22support leaders who are venal corrupt
  567. 22:27mal in whatever way. Okay.
  568. 22:31So, it's a nice model and if it were
  569. 22:33just a model and it is just a model in
  570. 22:35his version, it's nice enough that it
  571. 22:37makes this complicated dynamic problem
  572. 22:39very simple. You can see the moving
  573. 22:41parts and that's why it was published,
  574. 22:43you know, 20 years ago in the review of
  575. 22:44economic studies. It's a great paper.
  576. 22:49Okay, so this is just kind of the
  577. 22:51technique of it, which I think is nice
  578. 22:53too. It makes the problem simple, but I
  579. 22:54won't go into that too much. Now I want
  580. 22:56to tell you what my co-author and I did
  581. 23:00when we saw a an empirical fact in in
  582. 23:04Maharashtra. So we were collecting data
  583. 23:05there and we found this very unusual
  584. 23:08empirical pattern. We found that when a
  585. 23:11political office was reserved for a
  586. 23:13member of a particular cast and here it
  587. 23:16was OBC but just think about a cast
  588. 23:18that's not traditionally a powerful cast
  589. 23:21then mil village governance actually
  590. 23:24improved and the effect was concentrated
  591. 23:27uh in these OBC groups that were large
  592. 23:29but not super dominant and we found that
  593. 23:32the observed characteristics of the
  594. 23:34leader did little to account for the
  595. 23:36pattern. So it didn't seem like it was a
  596. 23:38improving the quality of people's
  597. 23:40standing per se. Okay. So normally we
  598. 23:43might have expected the following. So if
  599. 23:45you restrict who can stand for office,
  600. 23:47that means you're implying there's less
  601. 23:49competition and that means you're going
  602. 23:51to get worse governance.
  603. 23:53Okay, so that's what we would usually
  604. 23:55think, but we found that governance was
  605. 23:57improving. So what we realized was that
  606. 23:59the politics of fear model, that model
  607. 24:01that I just gave you, was able to affect
  608. 24:05a margin that could be explaining this
  609. 24:07data. Okay? So we cannibalized that
  610. 24:09model.
  611. 24:11Okay. The original model contained a lot
  612. 24:12of structure that just wasn't important
  613. 24:14in the Maharashtran village setting.
  614. 24:16Okay? There was activity specific t
  615. 24:18taxation. There was a particular form of
  616. 24:20specialization. These things weren't
  617. 24:22that relevant. And the reason is because
  618. 24:24the capacity to tax in that context was
  619. 24:26very low. And this specialization story
  620. 24:28just wasn't relevant for these different
  621. 24:30OBC groups.
  622. 24:33So what we did keep was what was
  623. 24:34essential and that is that basic
  624. 24:36equation that I showed you. The value of
  625. 24:38group control plus leader specific
  626. 24:40advantage and retaining it was
  627. 24:41generating the rent and what
  628. 24:44reservations political reservations were
  629. 24:46doing was essentially affecting the
  630. 24:49entry margin. They they affected who
  631. 24:51could compete for leadership.
  632. 24:54And when a reservation was given to a
  633. 24:56group, it meant that the competition had
  634. 24:58to come entirely from within because
  635. 25:00that group was guaranteed to win. Okay?
  636. 25:04So that original politics of fear model
  637. 25:07didn't have a process for replacing
  638. 25:09incumbents.
  639. 25:11But political reservation works
  640. 25:13precisely by changing that replacement
  641. 25:15possibility. Okay. So we built an
  642. 25:18extension which modeled the challenger
  643. 25:20entry and the governance offer that a
  644. 25:22challenge makes. So what often happens
  645. 25:24and this is what happened in this
  646. 25:25context that modeling in a particular
  647. 25:28context requires taking that off the
  648. 25:30path off off off the shelf model and
  649. 25:34making something which was relatively
  650. 25:38minor in that model here it was an off
  651. 25:40path behavior into the core of the
  652. 25:42model. So that's the case in a lot of
  653. 25:45those core models. They're focused on a
  654. 25:47generic economic context, but when you
  655. 25:49get a particular empirical setting, it
  656. 25:51tells you what you need to focus your
  657. 25:53model on. So we built down this
  658. 25:55extension and here we had two
  659. 25:58politically coherent groups or juties
  660. 26:00and the leader would obtain office
  661. 26:02rents. Citizens would value holding
  662. 26:04office and the leader would choose how
  663. 26:06much effort to put in. Okay. So I won't
  664. 26:09go into the details of that but
  665. 26:11essentially we took things that were not
  666. 26:13in that model and added them in but kept
  667. 26:15that core structure. So this was simpler
  668. 26:17than the original tax and patronage
  669. 26:19model of his but richer in the dimension
  670. 26:21where where the data was rich. Okay. So
  671. 26:24so what I want to tell you is this led
  672. 26:28to a set of very different predictions
  673. 26:31than his original model had. Okay. But
  674. 26:33it was still using the same idea. So
  675. 26:36here's what a reservation does in using
  676. 26:38the thinking of his model. So without a
  677. 26:41reservation, remember the probability
  678. 26:43that the group will hold office if they
  679. 26:46keep their leader is some gamma a
  680. 26:50uppercase. If they replace him with a
  681. 26:53challenger, it's gamma a lower case and
  682. 26:56this is lower. That's the cost of moving
  683. 26:58against an incumbent who might be
  684. 27:00terrible. That's the cost. So you have
  685. 27:02to risk losing control. With a
  686. 27:04reservation, both of those just go to
  687. 27:07one. So that difference collapses. Why
  688. 27:09does it go to one? Because essentially
  689. 27:13the electoral office says to you, you
  690. 27:15know, you've won. Your group has one
  691. 27:17office for sure. It's been reserved for
  692. 27:18you. That's going to change the law of
  693. 27:21motion of political power. And that
  694. 27:23changes everything in that model. So now
  695. 27:28the disciplining has come from entry
  696. 27:30from within. Before the disciplining on
  697. 27:32power was losing to another group, but
  698. 27:35that created a lot of bad problems for
  699. 27:38the constituents supporting the leader.
  700. 27:39Now you could throw out your leader.
  701. 27:42You're guaranteed to hold power. So the
  702. 27:45discipline now comes from who's going to
  703. 27:46want to challenge. What could how how
  704. 27:49good could they do? What can they
  705. 27:50promise you? So this changes the
  706. 27:52equilibrium by changing the off path
  707. 27:54behavior.
  708. 27:56So the incumbent's electoral advantage
  709. 27:58creates an equilibrium rent he consumes
  710. 27:59as lower governance in the politics of
  711. 28:02fear model with a reservation that's
  712. 28:04gone and so has the rent.
  713. 28:07So the model delivers
  714. 28:09essentially
  715. 28:11an empirical prediction which is one
  716. 28:13that we wanted to generate right that
  717. 28:17this was the level of governance in an
  718. 28:20unreserved village. It was whatever the
  719. 28:22first best was minus some amount. That's
  720. 28:25the politics of fear in the reservation.
  721. 28:29That level of governance, the difference
  722. 28:30between a reserved and an unreserved
  723. 28:34was positive. A reservation would
  724. 28:36improve governance. So this was
  725. 28:38generating the raw empirical fact that
  726. 28:41we found which of of course is step one.
  727. 28:44That's what you want a model to do.
  728. 28:46Okay. But
  729. 28:50and this should be the intuition. I
  730. 28:51won't go through it again, but it's on
  731. 28:52that slide if you want it again. It's
  732. 28:54essentially that it removes the
  733. 28:56political advantage of being the
  734. 28:57incumbent because now you can be
  735. 28:59challenged by anyone and the group
  736. 29:01doesn't lose power. Okay,
  737. 29:04but here's a non-obvious prediction. The
  738. 29:07model says the effects of reservation
  739. 29:10are governed by this initial difference
  740. 29:12between what would happen if you threw
  741. 29:14someone out and if you keep them. So if
  742. 29:17you had a very very take a strong group,
  743. 29:19a very strong group, they were
  744. 29:20guaranteed to win in any case.
  745. 29:23So in that case, these numbers, these
  746. 29:26gamas are close to one. That is, if they
  747. 29:28were strong, even if they threw a guy
  748. 29:29out, wouldn't matter. They were probably
  749. 29:31going to win anyway. In that case, a
  750. 29:33reservation is not going to have much
  751. 29:35effect because a reservation collapses
  752. 29:36this difference. But if the difference
  753. 29:38was small anyway, it's not going to do
  754. 29:39much. If you took a very weak group,
  755. 29:42they were very unlikely to win again.
  756. 29:44And then a reservation would also have
  757. 29:46little effect. So what this is telling
  758. 29:48you is there's a nonmonoticity. The
  759. 29:50model which was generated to explain the
  760. 29:53core correlation which is putting in a
  761. 29:56reservation improves governance tells
  762. 29:57you no no it's only going to happen if a
  763. 30:00group is like in the middle size where
  764. 30:02it could compete for power but it's not
  765. 30:04guaranteed to win it. That's where you
  766. 30:06should find it.
  767. 30:08So that tells you well if I can observe
  768. 30:10these things then I can test this model.
  769. 30:14I can test whether this story is the
  770. 30:15right story. And we can, you know, we
  771. 30:20could just basically look in unreserved
  772. 30:21villages and say, what is a what is a a
  773. 30:23group that is going to win for sure?
  774. 30:25What is a group that is almost never
  775. 30:26going to win? And here it is. If you had
  776. 30:29less than 25% of the village village
  777. 30:31population in your group, you won about
  778. 30:332% of the time. So then you're one of
  779. 30:35these groups that's almost never going
  780. 30:36to win. If you're above 50%, then you
  781. 30:40kind of have a plurality. You're almost
  782. 30:41always going to win. It's these groups
  783. 30:43in the middle where you should see it.
  784. 30:44So we could classify
  785. 30:46village structures, population
  786. 30:48structures and say here's the
  787. 30:49reservations that should really be
  788. 30:51driving our correlation in the data.
  789. 30:54And that's what happened. We we measured
  790. 30:56a bunch of observations uh different
  791. 30:59types of government governance uh
  792. 31:01quality effects and we found that the
  793. 31:03effects were only positive in these
  794. 31:07villages
  795. 31:08in the ones where that population of the
  796. 31:10reserve group was a particular size. if
  797. 31:12it was bigger or smaller in those
  798. 31:14extremes, it had no effect. So the the
  799. 31:17model hetrogenity was exactly what we
  800. 31:20saw in the data. We had no idea that
  801. 31:22this was going to be the case. We were
  802. 31:24just fishing around looking for models
  803. 31:26that could explain it. And when we found
  804. 31:28this one and we found the extra one,
  805. 31:29then the model generated a huge amount
  806. 31:32more value. And I started to believe it
  807. 31:34at that point. Before it was just a
  808. 31:36story, then I start believing it. There
  809. 31:38was another set of predictions which we
  810. 31:40also tested and I'm not going to go
  811. 31:43through them because I want to move on
  812. 31:44to talking about modeling more in
  813. 31:45general. Okay.
  814. 31:48So what did the modeling actually add
  815. 31:50here? What the modeling added was
  816. 31:57an explanation
  817. 31:59which came from totally left field. Like
  818. 32:02it wasn't the explanation that we
  819. 32:03thought would have been true.
  820. 32:06But when we started thinking about it
  821. 32:07and had to do stuff with it to make it
  822. 32:09fit our context, we found this other set
  823. 32:12of predictions and they fitted. They
  824. 32:14actually told us they they made us run
  825. 32:17regressions we would never have run
  826. 32:18before. We had no idea xante that this
  827. 32:20is what we would end up with
  828. 32:21empirically. But when we did them, they
  829. 32:24made sense. They made sense in the data
  830. 32:26and they started to give us a richer
  831. 32:28understanding of the original
  832. 32:29correlation that we that we built. Okay.
  833. 32:33So the model formalized the story and
  834. 32:36made predictions and then it took us way
  835. 32:37further than we could ever have gotten.
  836. 32:40Okay. So this is the model exercise in
  837. 32:43full a little bit more. I'm filling in a
  838. 32:45few more arrows here. We have an
  839. 32:47empirical puzzle. Essentially we don't
  840. 32:50we're not theorists in the sense of
  841. 32:52we're coming up with wholly different
  842. 32:53mechanisms. I mean some of you will do
  843. 32:55that at some point but mostly that's not
  844. 32:57the case. You just borrow a mechanism
  845. 32:59from one of these canonical models or
  846. 33:01from something else and then you throw
  847. 33:02out the bits of it that are built for
  848. 33:06the generality of the problem. A lot of
  849. 33:07them are not going to be relevant in
  850. 33:08your context.
  851. 33:10You're going to indogenize and and
  852. 33:12enrich the bit whether your data is rich
  853. 33:14and that will often depend on the
  854. 33:15institution. You'll solve the model.
  855. 33:17You'll derive conditions and some
  856. 33:19predictions from it. You construct then
  857. 33:21new data. You'll be driven by the model
  858. 33:23to look for new things and you test
  859. 33:25again. And that's what I mean by applied
  860. 33:28political economy modeling. And it may
  861. 33:31not seem obvious to you. It's very
  862. 33:32obvious to me that this is exactly what
  863. 33:34we do when we move from first learning
  864. 33:38about economics, which is essentially we
  865. 33:40build models, these very abstract
  866. 33:42things, and then we start thinking about
  867. 33:43the empirical. We don't do it the other
  868. 33:45way. I mean, you'll notice when you
  869. 33:47first do econ, you don't start with
  870. 33:49econometrics. You start with models.
  871. 33:53Okay. So, what's a toolkit here? Okay.
  872. 33:56So, so once you've seen one example then
  873. 34:01and once you've worked with this a few
  874. 34:02times the models become very easy to
  875. 34:04apply and again they're not a list of
  876. 34:06papers to memorize but when you're
  877. 34:09familiar with these models these are the
  878. 34:10ones that I'm telling you I think have
  879. 34:12useful structures that come up a lot in
  880. 34:15political economy contexts and the great
  881. 34:17thing about them is they're old so
  882. 34:19they're easy to read right they're
  883. 34:20written in a way that's you know often
  884. 34:23the first paper in in an area they have
  885. 34:24to do a lot of the handwaving and a lot
  886. 34:27of the contextual structure for you and
  887. 34:28they build it in a simple way so you can
  888. 34:30see the mechanisms clearly. If you
  889. 34:31understand these mechanisms, they're
  890. 34:32going to give you a set of tools that
  891. 34:34will be useful in lots of empirical
  892. 34:36context. These are the I'm just putting
  893. 34:38them
  894. 34:40these are the ones that were on the
  895. 34:41second slide. At at the end of the
  896. 34:43slides, I'm going to give you the
  897. 34:43precise uh readings for these, but I
  898. 34:46think these were shared with you anyway.
  899. 34:47So again, you don't need them for every
  900. 34:49model. You need to recognize when some
  901. 34:52of the structure in these models is
  902. 34:54coming up in an empirical problem. And
  903. 34:56sometimes multiple models will have
  904. 34:59a role in a in a particular empirical
  905. 35:01problem. All right? So they're not
  906. 35:05things you need to memorize, but they're
  907. 35:06like you could think of them like spare
  908. 35:08parts. Okay? You don't want to copy the
  909. 35:10structure of any particular one. So you
  910. 35:11don't want to rebuild that whole car,
  911. 35:13but you know, you want might want to
  912. 35:14take a part of that car. So it's a piece
  913. 35:17of machinery that helps you explain some
  914. 35:19fact that seems to be popping up for you
  915. 35:21in the data.
  916. 35:24Okay. So you you also and and you are
  917. 35:27you should and you will cannibalize
  918. 35:28models, right? So you'll take bits of
  919. 35:30them. You take bit of say this is just
  920. 35:31an example the par baron fedon
  921. 35:33bargaining model with a contest
  922. 35:35technology. That's a paper that that
  923. 35:36that you know that I built and and
  924. 35:39worked with others on to to to explain
  925. 35:41power sharing in in in African politics.
  926. 35:44Um and there's a bunch of other ways to
  927. 35:46put these things together. So you pull
  928. 35:47from different parts of these models to
  929. 35:49build your own model. Okay. So all also
  930. 35:52it's some of these models are really in
  931. 35:54a context got nothing to do the one that
  932. 35:56you're going to be studying empirically.
  933. 35:57So the corid soil model is a sort of a
  934. 35:59sender receiver model about
  935. 36:03asym asymmetries in information and how
  936. 36:04that affects signaling and and
  937. 36:06interpretation of signaling. This is not
  938. 36:08really couched as a political model. I I
  939. 36:11don't think in that paper that was even
  940. 36:12talked about in a political context. But
  941. 36:14this is an architecture that's really
  942. 36:16useful for thinking about a bunch of
  943. 36:17political economy interactions between
  944. 36:19parties and voters, bureaucrats and
  945. 36:21politicians, experts and citizens and
  946. 36:23lobbyists and policy makers because you
  947. 36:24can see in all those context there's
  948. 36:25that core essential information
  949. 36:28asymmetry and knowledge asymmetry and
  950. 36:30and that affects how signals are sent
  951. 36:32and how they're interpreted.
  952. 36:34Okay. So, so, so let me just kind of
  953. 36:36talk a little bit at overview level
  954. 36:38about um
  955. 36:41elements of the modeling, right? So,
  956. 36:42these are that was the kind of the
  957. 36:44political economy context. Now, there's
  958. 36:46kind of some some more general
  959. 36:47questions, right? So, so one first
  960. 36:49question is um how much model do you
  961. 36:51need? Right? So,
  962. 36:54if your model explains the mechanisms,
  963. 36:57generates predictions, tell you what
  964. 36:59tells you what to collect, then that's
  965. 37:01maybe enough. You should stop. And
  966. 37:04there's a question of parimony in in
  967. 37:06applied modeling that's very different
  968. 37:09in its in how you judge it relative to
  969. 37:11thinking about pure theory. Um so so I
  970. 37:16mean the way I think of it is in
  971. 37:19applied theory I'm always thinking what
  972. 37:21do I need minimally to get to the data
  973. 37:23and do interesting things with the data.
  974. 37:25In a true theory paper and a lot of the
  975. 37:29papers that are canonical models are
  976. 37:30written more like that. They're really
  977. 37:32looking for the generality of the
  978. 37:34result. How general is it? You know,
  979. 37:37when does it hold? When does it not
  980. 37:38hold? You know, really exploring
  981. 37:43the limits of the story. And sometimes
  982. 37:47that is going to be something useful for
  983. 37:48you because you can get predictions off
  984. 37:49that. But often all of that generality
  985. 37:52which is how we would judge a good
  986. 37:55theory paper like you know has it really
  987. 37:58fully illuminated the mechanism what's
  988. 38:00necessary what's sufficient that's not
  989. 38:02what you need in an applied paper. You
  990. 38:04just need
  991. 38:06a believable story that rationalizes the
  992. 38:10correlation. You need to make it clear
  993. 38:12that it's not your it's not being bought
  994. 38:14by some sort of cheap assumptions in the
  995. 38:16structure. But you can use very simple
  996. 38:18assumptions like even quadratic form or
  997. 38:20something. If it's clear that that's not
  998. 38:22what's buying it, that there's a deeper
  999. 38:23intuition, then you can generate the
  1000. 38:25results from that. So that wouldn't fly
  1001. 38:26as a theory paper, but as an applied
  1002. 38:28theory paper, that's exactly the level
  1003. 38:30you want to be at. You don't want to do
  1004. 38:31all that machinery for nothing. Okay. So
  1005. 38:34when do you need more structure? So this
  1006. 38:36is
  1007. 38:38well, we'll think about what structure,
  1008. 38:39what I mean by structure in a second. So
  1009. 38:41So if you want to ask questions like
  1010. 38:42this, what happens if you were to
  1011. 38:44fundamentally change the system? change
  1012. 38:46the voting rule, change a term limit. So
  1013. 38:49you might put in a term limit when there
  1014. 38:51aren't term limits for political office.
  1015. 38:53Um you want to change who's eligible to
  1016. 38:55stand. What happens essentially under an
  1017. 38:58institution that you never observe in
  1018. 39:00the data.
  1019. 39:02So now the observed reduced form
  1020. 39:06relationships aren't going to be enough
  1021. 39:07because you're not observing these
  1022. 39:08things. But if you can believe that some
  1023. 39:11of them are invariant to these changes
  1024. 39:13and this is where you have to make the
  1025. 39:14assumption and and find it believable
  1026. 39:17then you can run counterfactuals
  1027. 39:19along these lines under the assumption
  1028. 39:21that the parameters that you estimated
  1029. 39:24initially in the data will hold across
  1030. 39:27the counterfactuals. So that's when you
  1031. 39:29can do structural modeling and that's
  1032. 39:30when it's worthwhile to do it. So here
  1033. 39:33you're going to make assumptions that
  1034. 39:35will essentially be stronger than in the
  1035. 39:38simple reduced form world. But with
  1036. 39:40those stronger assumptions, you're going
  1037. 39:41to be able to get more results. Results
  1038. 39:45about things that would be more like
  1039. 39:46systemic change. Now that comes at a
  1040. 39:50cost. The cost is those assumptions.
  1041. 39:53So those are stronger claims, right? So
  1042. 39:56you're you're starting from primitives
  1043. 39:58that you are taking much more seriously
  1044. 40:00and actually much more literally, right?
  1045. 40:02So preferences, technology, information,
  1046. 40:04institutions, stocks, all those things
  1047. 40:05are things that are now going to
  1048. 40:06generate your equilibrium.
  1049. 40:08So you're actually going to generate the
  1050. 40:10data with your model. You're generating
  1051. 40:14a rationalization of the data from your
  1052. 40:16model. And you're going to be when it's
  1053. 40:17useful is when you can hold those
  1054. 40:19primitives, at least some of them fixed.
  1055. 40:22So primitives on preferences,
  1056. 40:23technology, and claim that those things
  1057. 40:24are going to be invariant to the the try
  1058. 40:26to change that I'm imagining. then
  1059. 40:28you're going to get predictions about
  1060. 40:29the world that would happen in that very
  1061. 40:32different counterfactual world and that
  1062. 40:34can be useful when when people will buy
  1063. 40:36when you buy and when people will buy
  1064. 40:38that those things are invariant
  1065. 40:40and if they won't then it's a useless
  1066. 40:42exercise right so so I've certainly met
  1067. 40:45people who argue for doing this sort of
  1068. 40:47structural work for or not doing it for
  1069. 40:49the wrong reasons right so I I mean
  1070. 40:52maybe people don't do this anymore but
  1071. 40:54when it was when I was in grad school I
  1072. 40:56heard people saying this structural
  1073. 40:57models are just better because they're
  1074. 40:59more rigorous. They, you know, they they
  1075. 41:01have more math. There's more theory.
  1076. 41:02They take theory seriously. That's not a
  1077. 41:04good reason to do it. To me, the good
  1078. 41:06reason to do it would be, oh, if I can
  1079. 41:08actually understand something that I
  1080. 41:10couldn't understand by doing the simple
  1081. 41:11reduced form model, that's a good reason
  1082. 41:14under a set of assumptions that people
  1083. 41:15find believable, then okay, then it's
  1084. 41:18worthwhile doing. And some people just
  1085. 41:21start with an exit position that oh
  1086. 41:23taking this like assuming preferences
  1087. 41:25like nobody knows what the preference
  1088. 41:26you can't just assume that structural
  1089. 41:28models are never believable. I find that
  1090. 41:30also an un an unconvincing reason to not
  1091. 41:33do it. So I think they're they're both
  1092. 41:35the wrong way to proceed. You should ask
  1093. 41:37what question can I answer with the
  1094. 41:39additional structure that I cannot
  1095. 41:40answer without it? If none not at all
  1096. 41:43then the question is is that structure
  1097. 41:45believable? believable enough in
  1098. 41:48believable enough to be invariant. Okay,
  1099. 41:50then then it's worth doing.
  1100. 41:54Okay, so that's my two cents on
  1101. 41:57structural modeling when to and when
  1102. 41:58not. And for me as an applied theorist,
  1103. 42:01I've done both and in different contexts
  1104. 42:03I think they're useful. Okay, so now
  1105. 42:07this has changed things a lot. So LLMs
  1106. 42:10have changed the technology of model
  1107. 42:13building and they've changed it in
  1108. 42:16mostly a good way and you should utilize
  1109. 42:20them. I utilize them. They are useful
  1110. 42:22for building models. The latest
  1111. 42:24generation are two years ago. They
  1112. 42:26weren't. A year ago they weren't that
  1113. 42:27much. Now they're pretty useful. They're
  1114. 42:30not perfect, but they do these things
  1115. 42:32pretty well. You need to check them. But
  1116. 42:34this is what they can do well. They can
  1117. 42:35do algebra. And for someone like me that
  1118. 42:37is just my life was littered with
  1119. 42:41algebra errors. So I would for me
  1120. 42:44algebra is a statistical process. What I
  1121. 42:46mean is I do things five times and if
  1122. 42:47two of them are the same then I would
  1123. 42:49assume that that was the right one. So
  1124. 42:51I'm terrible at algebra. So this made my
  1125. 42:53life so much better. Right? So now I can
  1126. 42:56just check it. I check one it looks
  1127. 42:57right. I'm so happy. Derivations
  1128. 42:59comparative statics trying alternative
  1129. 43:01functional forms. So exploring elements
  1130. 43:03of the model space that would have taken
  1131. 43:04a long time. You can do it easy checking
  1132. 43:07candidate models, generating several
  1133. 43:09modeling approaches quickly. So you have
  1134. 43:11some vague ideas, you put it in, it
  1135. 43:13gives you some structure and you can
  1136. 43:15think is this capturing it well or not?
  1137. 43:17If it is, then you can say, well, you
  1138. 43:18know, what are the things this is giving
  1139. 43:19me? You can do this fast now. This is
  1140. 43:21fantastically valuable. It's an enormous
  1141. 43:24improvement in our research technology.
  1142. 43:27So what's become scarce? Something has
  1143. 43:29become scarce now. So if models can
  1144. 43:31generate
  1145. 43:33many at one time like 10 at once
  1146. 43:37then the scarce input becomes what it
  1147. 43:40becomes actually thinking and and you
  1148. 43:42can't see thinking where do you see it
  1149. 43:44where do you see the effects of it it's
  1150. 43:45good judgment
  1151. 43:47so building intuitive parimonious real
  1152. 43:52illuminating defensible to you and by
  1153. 43:54you models it's not always good at doing
  1154. 43:58that so that you are still very much
  1155. 44:01involved in the loop. So, it's giving
  1156. 44:02you a sort of a a big leg up over a lot
  1157. 44:06of elements of the model building, but
  1158. 44:08it's not taken us um primates out of the
  1159. 44:11model building process yet.
  1160. 44:15Okay? And and and you can see like we
  1161. 44:17used to be at least when I was in grad
  1162. 44:19school, we were we I was impressed by
  1163. 44:20people's mathematical capacities. Not
  1164. 44:22just because, you know, there's this
  1165. 44:24kind of thing that a lot of economists
  1166. 44:25have, which is like if you if you're
  1167. 44:26math, you're just smart. It was because
  1168. 44:28they could explore the model space very
  1169. 44:30fast. They could explore this kind of
  1170. 44:32weird world, right? This abstract space
  1171. 44:34of modeling. If you're good at math,
  1172. 44:36that's the language of models. They
  1173. 44:37could explore it fast and that's
  1174. 44:38valuable. So, that was impressive.
  1175. 44:40That's not impressive anymore. Okay. So,
  1176. 44:42now we're increasingly asking, you know,
  1177. 44:44why why are you building this
  1178. 44:45complicated machinery? What's the
  1179. 44:47algebra doing? Is it worth doing? Why
  1180. 44:49couldn't things be simpler? And and more
  1181. 44:51importantly, what do you actually
  1182. 44:53believe? What can you defend?
  1183. 44:57Okay. So, you have to own your model.
  1184. 45:01That means what? You should use the LMS
  1185. 45:03to build them. Absolutely, you should.
  1186. 45:04And I put should in capital letters cuz
  1187. 45:06actually you're wasting time if you
  1188. 45:09don't. I think you should. And I don't
  1189. 45:12know where that should be inserted. It's
  1190. 45:14different for everyone, but I think they
  1191. 45:15they are a valuable tool. We should be
  1192. 45:17using them. But if it helps you build
  1193. 45:18the model, by the time you present it,
  1194. 45:20it still has to be your model. So you
  1195. 45:22should know why every assumption is
  1196. 45:24there, what results depend on them, what
  1197. 45:26happens if you pull something out,
  1198. 45:29why you rejected alternatives. You have
  1199. 45:31to thought through all the alternatives
  1200. 45:32and why you rejected them. Okay? It
  1201. 45:34should become something like, you know,
  1202. 45:35when you when you have a very good
  1203. 45:36friend, you know them so well. You know
  1204. 45:38how they'll react even in situations
  1205. 45:40that that you haven't seen them in. you
  1206. 45:42just know, oh boy, if you know, I know
  1207. 45:43what they're going to do here even
  1208. 45:44though I have, you know, that's that's
  1209. 45:46the way you have to know your model. It
  1210. 45:48has to be completely familiar to you.
  1211. 45:52So that's the test, right? And this is
  1212. 45:54the test that's increasingly becoming a
  1213. 45:56big part of our profession. We using it,
  1214. 45:58I'm using it all in my grad courses now.
  1215. 46:00It's actually getting up and presenting
  1216. 46:02your model and defending it against
  1217. 46:04questions like this and worse questions
  1218. 46:06and more difficult questions that you
  1219. 46:08get. Why do you need that assumption?
  1220. 46:09Why is information private? Why was this
  1221. 46:12the sequencing? What happens if I change
  1222. 46:13the sequencing that seems arbitrary?
  1223. 46:15Couldn't another mechanism generate the
  1224. 46:17same fact? Have you thought about that
  1225. 46:18other mechanism? What do you think about
  1226. 46:20it now? What happens if I remove
  1227. 46:22something in the model?
  1228. 46:25That intuition has to be very clearly in
  1229. 46:28your mind. And you can't just say, well,
  1230. 46:29that's in the appendix, right? That now
  1231. 46:32it's it's even worse than it used to be
  1232. 46:34if you said it because now it just makes
  1233. 46:35it look like, well, you actually didn't
  1234. 46:36generate your model. You don't own it.
  1235. 46:39And here's the last bit. very important.
  1236. 46:42LLMs are not good at attributing. Okay?
  1237. 46:46So, they will take they will do what I
  1238. 46:48said to you, right, which is cannibalize
  1239. 46:51a model and give you something that's
  1240. 46:53useful, but they don't tell you what
  1241. 46:54model they cannibalize. They're very bad
  1242. 46:56at that. You have to really push them to
  1243. 46:59do it. And so, that may just be a a bug
  1244. 47:04and that might be changed through time
  1245. 47:06as the LM become better, but right now
  1246. 47:08that's the case. So, so you can say,
  1247. 47:11"Oh, I've got this vague idea from a
  1248. 47:13model." And it goes, "Hey, yeah, like I
  1249. 47:14I think this is what you should do." And
  1250. 47:16it gives you a formalization that's just
  1251. 47:18completely lifted from someone else,
  1252. 47:20right? Who also had the vague idea maybe
  1253. 47:22in a different context. You have to site
  1254. 47:23that paper. You have to push the LM to
  1255. 47:26tell you what is this like, where did
  1256. 47:28you get this? Is does it resemble
  1257. 47:30anything? You have to push it hard right
  1258. 47:31now for it to give you that information.
  1259. 47:33And if you don't and if you take a model
  1260. 47:36that someone else's that the LLM gave
  1261. 47:38you, you are responsible for that. And
  1262. 47:40that is plagiarism, right? You're
  1263. 47:42responsible ultimately for that. So you
  1264. 47:44have to do a deep dive and make sure
  1265. 47:46that whatever it's giving you, you go
  1266. 47:48and find the paper and you read that
  1267. 47:50paper and you site it properly. Okay? If
  1268. 47:52not, then I put that in bold at the end.
  1269. 47:55I have seen careers ended by that sort
  1270. 47:57of not not in the LLM context, it's too
  1271. 47:59early, but by plagiarism. Okay?
  1272. 48:02you that's the one thing you don't want
  1273. 48:03to be. You have to be correctly
  1274. 48:05attributing. Okay.
  1275. 48:08Okay. So let's me go to sort of the over
  1276. 48:10overview level a bit.
  1277. 48:12These are five questions to ask when you
  1278. 48:13have a new empirical result. What is the
  1279. 48:15simplest economic environment that could
  1280. 48:17generate that fact?
  1281. 48:20You have to think about what should be
  1282. 48:22primitive? What should emerge? And those
  1283. 48:23canonical models in particular contexts
  1284. 48:25are going to help you that they're
  1285. 48:27exactly doing that. Then what else has
  1286. 48:30to be true? If the mechanism that I'm
  1287. 48:33I'm suggesting is the one that works,
  1288. 48:35what has to be true if that's correct,
  1289. 48:38then think about more broadly what
  1290. 48:40competing mechanisms could explain the
  1291. 48:41same fact and what data would help you
  1292. 48:43to distinguish between them. And then
  1293. 48:46when do I stop? Do I have enough model?
  1294. 48:49Is there something else I can get for it
  1295. 48:51from it? Maybe then I could maybe if I
  1296. 48:53want to look at a different sort of
  1297. 48:55world that might be an important policy
  1298. 48:56world, maybe I want to put more
  1299. 48:58structure in. These are the questions
  1300. 49:00that come to me when I do model
  1301. 49:04building. And like I said, I mostly work
  1302. 49:07with empirical people who come to me
  1303. 49:09with I mean there's two sorts of
  1304. 49:11situations that I kind of do this model
  1305. 49:13building for. One is with students. So
  1306. 49:15it's it's remarkable. We used to learn
  1307. 49:17this kind of skill because a lot of the
  1308. 49:19fields were much more theoretical. So we
  1309. 49:21would see these canonical models and
  1310. 49:23work with them. Now so much of the work
  1311. 49:25and this is a good thing but we have
  1312. 49:27evolved towards doing much more
  1313. 49:29databased work. So many students will
  1314. 49:32just have they're swimming in data and
  1315. 49:34have a bunch of correlations and then
  1316. 49:36they come to people like me and say my
  1317. 49:39supervisor said I have to come up with a
  1318. 49:41story to rationalize this and you know
  1319. 49:44that's good but the story can be much
  1320. 49:46more than just a rationalization and it
  1321. 49:48should be otherwise and I see this a lot
  1322. 49:50people are just putting in math what
  1323. 49:52they could put in English and calling it
  1324. 49:53an empirical model it's totally useless
  1325. 49:56you might as well just say it in English
  1326. 49:57the model has to do the work of
  1327. 49:59generating something new for you
  1328. 50:01empirically, not just rationalizing the
  1329. 50:04fact.
  1330. 50:06So, so what I want you to leave this uh
  1331. 50:09talk with and I'm happy to take Q&A, but
  1332. 50:11here's the kind of um
  1333. 50:15questions that I and the thinking that I
  1334. 50:17want you to take away. So, so when you
  1335. 50:19see an empirical pattern, you shouldn't
  1336. 50:22think the first thing shouldn't be you
  1337. 50:24thinking what regression should I run
  1338. 50:26next. um should also ask what's the
  1339. 50:30environment that generated this
  1340. 50:31empirical pattern
  1341. 50:34and that's going to tell you what else
  1342. 50:36you should run next. That's going to
  1343. 50:38tell you what that particular
  1344. 50:40environment those moving parts
  1345. 50:44are generating empirically and then you
  1346. 50:45go and run that. So, so like with supply
  1347. 50:48and demand, right? If you just saw a
  1348. 50:50bunch of correlations between quantities
  1349. 50:51and prices, you could think about, okay,
  1350. 50:54maybe I should run a sort of a different
  1351. 50:56specification. Maybe I should put in a
  1352. 50:58squared term or something. It's totally
  1353. 51:00useless to do it that way. But when you
  1354. 51:02start thinking about supply and demand,
  1355. 51:03when that's deeply embedded into how you
  1356. 51:05think about that context, then it gives
  1357. 51:07you a different structure. Now I'm
  1358. 51:09thinking, oh, well, what are things that
  1359. 51:11could move the supply curve maybe
  1360. 51:13exogenously that would allow me to
  1361. 51:15identify the demand curve? It totally
  1362. 51:17structures how you think. So that way of
  1363. 51:19thinking which I think is deeply
  1364. 51:21embedded how we think about
  1365. 51:23the most simple context should be
  1366. 51:26embedded in how we think in political
  1367. 51:27economy context as well. And what I'm
  1368. 51:29suggesting is those canonical models
  1369. 51:32give you that set of tools for thinking
  1370. 51:34that way. They're just like the supply
  1371. 51:36and demand of the standard market.
  1372. 51:40So the objective is essentially is to
  1373. 51:42move from an empirical fact.
  1374. 51:46This is the correlation that you found
  1375. 51:48set of facts and
  1376. 51:51think about the story which is the
  1377. 51:53economic mechanism. Then build a model
  1378. 51:57use whatever tools you need to do that.
  1379. 51:59But you have to own it.
  1380. 52:02That model should give you new things to
  1381. 52:04look for in the world. And when you
  1382. 52:07found those things, if they fit, then
  1383. 52:09you actually have a paper. If they don't
  1384. 52:11fit, tells you that's not a good model.
  1385. 52:12Go back and think about it again. So, it
  1386. 52:15all comes from this this position that,
  1387. 52:18you know, I have um which is a kind of
  1388. 52:20an an act of faith in a sense, right?
  1389. 52:23It's like I think that the economic way
  1390. 52:25of thinking actually does generate
  1391. 52:27insights into the world. So if I find a
  1392. 52:31set of correlations that don't make
  1393. 52:32sense, I try to think of them with a an
  1394. 52:35economic model and if that model
  1395. 52:37generates predictions and they fail,
  1396. 52:39then I don't say, well, this is just a
  1397. 52:41mystery. We'll never be able to
  1398. 52:42understand it. I think no, there
  1399. 52:43actually must be a different model. And
  1400. 52:45I will keep exploring the model space
  1401. 52:48till I find the one that makes sense.
  1402. 52:50And in fact, the best thing is if the
  1403. 52:52first five models don't work, they
  1404. 52:54generate predictions that don't work,
  1405. 52:55then you've got a super interesting
  1406. 52:57motivation for a paper, right? It's
  1407. 52:59like, look, you may think it's X. Well,
  1408. 53:01model X generates this and that just
  1409. 53:03doesn't fit. You may think it's Y. Then
  1410. 53:05you can say, here's my model, which is
  1411. 53:07this super weird funky thing, but that
  1412. 53:09actually fits. Then you've got a great
  1413. 53:12paper. So
  1414. 53:16I think political economy is for that
  1415. 53:19process. Political economy is a set of
  1416. 53:22theories firstly explanations for the
  1417. 53:24world that we use to generate deeper
  1418. 53:28ways of going into the world into the
  1419. 53:32data.
  1420. 53:34Okay. So those are the papers I think
  1421. 53:36the reading list has been circulated
  1422. 53:38with you but I that I think are great
  1423. 53:39papers to read that have helped me a lot
  1424. 53:41in thinking about different political
  1425. 53:43economy contexts. Um I think uh I that's
  1426. 53:48really all I wanted to say. So that's
  1427. 53:50I'm now happy to take questions and I
  1428. 53:52think Caleb's going to moderate the
  1429. 53:53questions and um just far away. I can
  1430. 53:57stop screen sharing Caleb.
  1431. 54:00>> Sure. Yeah, that that works great.
  1432. 54:02>> Okay.
  1433. 54:06So, uh if anyone has questions, they
  1434. 54:09there's many that have been coming in
  1435. 54:11through the Q&A box, but now's a good
  1436. 54:13time to send through any more for for
  1437. 54:15Patrick if you have them. I'll start
  1438. 54:17with what we have and we'll
  1439. 54:20begin with uh the live participants here
  1440. 54:23and we'll just kind of go back and forth
  1441. 54:24like we have in in the other lectures.
  1442. 54:27So um I'm going to murder this. Kar Sara
  1443. 54:31Van would you like to go first?
  1444. 54:33>> Yes.
  1445. 54:33>> Yeah. Uh hi Patrick thank you so much
  1446. 54:35for the presentation. It's quite
  1447. 54:36interesting. My question is related to
  1448. 54:38the political reservations in um the
  1449. 54:41village of Maharashtra that you spoke
  1450. 54:43about like whether the the socioeconomic
  1451. 54:46uh status of Pradhan influence the
  1452. 54:49governance mechanism because since we
  1453. 54:50work with village punays what happens is
  1454. 54:53that these pradans they don't get
  1455. 54:55salaries or like a proper hondorium. So
  1456. 54:58my question is like on that context
  1457. 55:01where does the socioeconomic status of
  1458. 55:04Pradan makes sense or does it uh you
  1459. 55:08know bring uh changes in the governance?
  1460. 55:11>> So it's a good question absolutely and
  1461. 55:13and especially in that context. So um
  1462. 55:16but let me just kind of because I think
  1463. 55:18it's a it's sort of a little bit uh a
  1464. 55:21very specific question that's not
  1465. 55:22related to the overall theme of the
  1466. 55:23lecture. I wanted to give that as an
  1467. 55:24example but I think there is something
  1468. 55:26related to the theme of lecture in your
  1469. 55:27question. So I want to kind of touch on
  1470. 55:29that. So in that context one of the
  1471. 55:32first things we thought was look the
  1472. 55:34type of person that's getting the office
  1473. 55:36now is going to be different than the
  1474. 55:37type before and that's going to be
  1475. 55:39related to social economic status
  1476. 55:41education maybe landholding maybe uh
  1477. 55:45wealth in other ways you know
  1478. 55:47we found and that was the first place we
  1479. 55:49looked. So you know when we saw this
  1480. 55:51pattern of reservations acting in a
  1481. 55:53certain way we found that to be
  1482. 55:57unimportant. So we we we had pretty good
  1483. 55:59measures of it and it just wasn't moving
  1484. 56:01the variables at all. So so that was one
  1485. 56:04of the things we conjectured. So in a
  1486. 56:05sense that's a theory that we explored
  1487. 56:07in a very preliminary way with the data
  1488. 56:09and ruled out pretty quickly. And also
  1489. 56:12when we once we had developed our theory
  1490. 56:15it generated this non-monotonicity
  1491. 56:16prediction. And then we went back and
  1492. 56:18thought well look maybe we just didn't
  1493. 56:21measure those observables about predan
  1494. 56:23type very well if we had measured them
  1495. 56:25maybe there's mismeasurement there maybe
  1496. 56:28that is still important could that
  1497. 56:30generate the nomotenicity so we thought
  1498. 56:32through that theory we resurrected it
  1499. 56:33again thought could it explain our data
  1500. 56:35and it didn't generate it so it actually
  1501. 56:38failed in terms of the empirical
  1502. 56:40observables and then once we had the the
  1503. 56:42kind of interesting extra results from
  1504. 56:43the other theory which were confirmed in
  1505. 56:45the data we went back to that theory and
  1506. 56:47it also didn't make of it. So, so it
  1507. 56:49comes up a lot when you know and this is
  1508. 56:50one of those things when we gave the
  1509. 56:51talk people like oh no they had your
  1510. 56:54intuition that this might be an
  1511. 56:55important thing and we could rule it out
  1512. 56:57for those two reasons. One is it didn't
  1513. 56:59fit in in our raw data it just wasn't
  1514. 57:02doing anything but two even it would be
  1515. 57:04very hard to rationalize our empirical
  1516. 57:06finding with that story. So that that
  1517. 57:09seemed to me that was kind of very much
  1518. 57:11part of the modeling process is to
  1519. 57:13consider theories like that one and
  1520. 57:14others in in context. Yes.
  1521. 57:17Good question.
  1522. 57:18>> Thank you.
  1523. 57:20>> Perfect. Um, there have been a few
  1524. 57:23questions in in the chat kind of I think
  1525. 57:27going back to what you were saying more
  1526. 57:28about the beginning around kind of where
  1527. 57:31you getting your data from and what the
  1528. 57:32role of theory is. And I I think many
  1529. 57:35researchers um are told that you can
  1530. 57:38either you know start with a big theor
  1531. 57:39theoretical question and then seek
  1532. 57:41evidence and others are told to begin
  1533. 57:43with that empirical pattern or work
  1534. 57:45backwards towards a mechanism and so in
  1535. 57:48your own work maybe how do you move
  1536. 57:50between theory and data and what
  1537. 57:52distinguishes a productive interaction
  1538. 57:55>> yeah so uh okay so I think it's very
  1539. 57:58risky to start with I had this theory
  1540. 58:02about the universe
  1541. 58:04and I'm going to formalize it and uh
  1542. 58:08then it's going to generate some
  1543. 58:09predictions and it's going to take me
  1544. 58:11like a year or two to formalize it and
  1545. 58:13then uh I'm going to look for data.
  1546. 58:16Maybe there'll be some data that could
  1547. 58:17speak to it and uh and then and
  1548. 58:21hopefully the data fits. I mean that's
  1549. 58:23just like a fantastically
  1550. 58:25scary undertaking I think for a PhD
  1551. 58:28student, right? Like, so once you're me
  1552. 58:30and I got tenure, then I actually do do
  1553. 58:32things like that now, right? I mean, I
  1554. 58:34it wouldn't be my whole job because if I
  1555. 58:36if that was the only thing I did, I'd
  1556. 58:37feel embarrassed cuz for 10 years I
  1557. 58:39wouldn't publish, right? And then maybe
  1558. 58:40I publish something. So, but I do I have
  1559. 58:43these things going on in the background.
  1560. 58:44So, I wrote a paper recently on
  1561. 58:45consciousness, right? Which is like
  1562. 58:47totally wildly not economic and it was a
  1563. 58:50form of that. It's a pure theory piece.
  1564. 58:52But I find that as if an applied
  1565. 58:54theorist, I mean, there are people who
  1566. 58:56are doing theory and they're making the
  1567. 58:57tools that we think that's fine. And I'm
  1568. 58:58not talking about that for the applied
  1569. 59:00theorist who's trying to explain
  1570. 59:00something in the world, I think it's a
  1571. 59:02very risky way to start. So, so that
  1572. 59:04kind of stylized conception that we come
  1573. 59:06up with a a theory and it's kind of
  1574. 59:08sealed and then we we we we look at we
  1575. 59:12fully, you know, instantiate that theory
  1576. 59:14in a model and then we look for data to
  1577. 59:16test it. That's that's not really how
  1578. 59:19this process can work. I just don't
  1579. 59:21think it's feasible. What I think is
  1580. 59:22feasible is
  1581. 59:24the world now throws up a lot of data in
  1582. 59:28a way that it didn't when I was in grad
  1583. 59:29school. So now you can just create data
  1584. 59:31sets so quickly and you can access data
  1585. 59:33sets so quickly and most of that data is
  1586. 59:36in the social realm. So it's really
  1587. 59:38begging for theoretical economic
  1588. 59:40explanation. So that's the way it
  1589. 59:43usually works. You come up with data,
  1590. 59:44you find these interesting things.
  1591. 59:47Sometimes it can really establish great
  1592. 59:49causal relations. So it fits all the
  1593. 59:51kind of tests of um identification. Then
  1594. 59:54you think about what what does it mean?
  1595. 59:57How do I explain it? And if if that
  1596. 1:00:00process is rich, what I mean is that
  1597. 1:00:03story which will rationalize it will
  1598. 1:00:05give you more things to look at in the
  1599. 1:00:06data and then you have a great project.
  1600. 1:00:08Because I'm always thinking when I'm
  1601. 1:00:11doing a project, how am I going to stand
  1602. 1:00:13up in front of a room of skeptical
  1603. 1:00:14economists who each have their own ideas
  1604. 1:00:16which are not the same as mine and
  1605. 1:00:18convince them that this is something
  1606. 1:00:20that's worth an hour and a half of their
  1607. 1:00:22time. And it's like that here's this new
  1608. 1:00:24set of facts that you didn't know about
  1609. 1:00:26before. That's not enough. Cuz most
  1610. 1:00:28people say, "Yeah, okay, big deal. What
  1611. 1:00:29does it mean?" I tell them what it means
  1612. 1:00:31and I defend it. So I say, "Look, you
  1613. 1:00:34know, here's a way of making sense of
  1614. 1:00:35it." And then they're like most
  1615. 1:00:37economists there's 30 people in the
  1616. 1:00:39room. There'll be 40 different opinions,
  1617. 1:00:41right? No, no, this is not it. It's
  1618. 1:00:42something else. It's this thing. God,
  1619. 1:00:44how can you claim that? So people just
  1620. 1:00:46come up and then you say, "Okay, here's
  1621. 1:00:48my story." And it generates these seven
  1622. 1:00:51other predictions. And your stories
  1623. 1:00:53don't do that. I know that. I thought
  1624. 1:00:54about some of them. They'd be very
  1625. 1:00:56surprised if they did. And then they
  1626. 1:00:58fit. Then you then you've taken somebody
  1627. 1:01:00from skepticism to like, "Oh, yeah, so
  1628. 1:01:04what?" to like, oh, that's kind of cool.
  1629. 1:01:06I think it's just a human thing. We just
  1630. 1:01:08like explanation. We like a story or a
  1631. 1:01:10parable or myth that makes makes sense
  1632. 1:01:14of the observables. And if I can say,
  1633. 1:01:16look, this one seems to fit, then that
  1634. 1:01:18that's just interesting to people. So, I
  1635. 1:01:21think that that process is a better
  1636. 1:01:22process for a PhD student is to take the
  1637. 1:01:24the data first, enrich it with a story
  1638. 1:01:27and a theory, and then do more data
  1639. 1:01:30based on that enriching. That's that's a
  1640. 1:01:32more feasible one. So I know it's not
  1641. 1:01:33pure science cuz I think we have this
  1642. 1:01:35pure science view. We we we come up with
  1643. 1:01:37theories in the abstract like you know
  1644. 1:01:40and then we just go and test them in the
  1645. 1:01:41empirical world. I don't think that's
  1646. 1:01:42how it is. It's a back and forth.
  1647. 1:01:47>> Thank you. I think I think that really
  1648. 1:01:49hits home to some of the the root of
  1649. 1:01:51some of these questions.
  1650. 1:01:53Assuming then that we do start with uh
  1651. 1:01:56the data first and we're we're going
  1652. 1:01:59from there. When several models appear
  1653. 1:02:02that are consistent with the data, what
  1654. 1:02:04do you use to decide amongst them? Do
  1655. 1:02:07you prioritize predictive performance,
  1656. 1:02:10parsimony, externability like h how do
  1657. 1:02:12you how do you decide which out of all
  1658. 1:02:13the models that come from your data to
  1659. 1:02:16go with?
  1660. 1:02:17>> Yeah. So sometimes, you know, I think
  1661. 1:02:19it's a combination of things. So the
  1662. 1:02:21reality is, you know, we have this view
  1663. 1:02:22of like these Okams rays are the most
  1664. 1:02:24parsimonious one, but sometimes people
  1665. 1:02:26just find the parimonious explanation
  1666. 1:02:28not to be real. So you know if they're
  1667. 1:02:30really equivalent on observables at
  1668. 1:02:32least you know there may be all models
  1669. 1:02:35are going to have some differential
  1670. 1:02:36predictions but in might be that those
  1671. 1:02:38are in in realms that are not
  1672. 1:02:39observable. So if they're equivalent on
  1673. 1:02:42the observables
  1674. 1:02:43then I think the right thing to say is
  1675. 1:02:45look I have a class of models that vary
  1676. 1:02:48on some dimensions that's why they're a
  1677. 1:02:50class and they're going to differ on
  1678. 1:02:51some of these but those differences
  1679. 1:02:53are in dimensions that we just don't
  1680. 1:02:56have the data to collect. I can I could
  1681. 1:02:58tell you the experiments that you would
  1682. 1:02:59need to run but you know it's not
  1683. 1:03:01feasible for me as a student to run them
  1684. 1:03:02but so I don't I don't wed myself to one
  1685. 1:03:06of those particular ones because I don't
  1686. 1:03:08have a good reason to do it at that
  1687. 1:03:09point and I don't need to. If I say look
  1688. 1:03:11it's a class of models and there may be
  1689. 1:03:13variation on these at the fringes of
  1690. 1:03:15those models that would be generating
  1691. 1:03:17other predictions but I can't do them
  1692. 1:03:18then I just say I commit to that class
  1693. 1:03:20of models that class of models is
  1694. 1:03:21generating a set of predictions that are
  1695. 1:03:24in the data and that's what I'm going to
  1696. 1:03:26tell you about. Now when I'm giving the
  1697. 1:03:28narrative you know when you're giving a
  1698. 1:03:30narrative on a model it's very hard to
  1699. 1:03:31do a class of models because they're all
  1700. 1:03:33a little bit different. Then I pick the
  1701. 1:03:34one that I think isn't necessarily the
  1702. 1:03:36parimmonious one. I usually pick the one
  1703. 1:03:38that I think is the most compelling, the
  1704. 1:03:40most compelling story. And and again,
  1705. 1:03:42that's important, you know, like most
  1706. 1:03:44people, I mean, we learn to not do this,
  1707. 1:03:46but most people, at least when they
  1708. 1:03:48approach a newspaper, they approach it
  1709. 1:03:49like they do reading a newspaper
  1710. 1:03:51article. Newspaper articles doesn't give
  1711. 1:03:52you, it gives you a little bit of stats,
  1712. 1:03:54but it's often with a narrative. So
  1713. 1:03:55those compelling narratives, I think,
  1714. 1:03:57are very important. But the but I think
  1715. 1:03:59that's part of the pitch of a paper and
  1716. 1:04:02a talk. But you know, in the end, if you
  1717. 1:04:04have a class of models that are
  1718. 1:04:06indistinguishable, you have to say, "No,
  1719. 1:04:08no, all of those are on the table at
  1720. 1:04:10this point. This is all I can do with
  1721. 1:04:11the data. I can just tell you it's one
  1722. 1:04:13of these or maybe all of these or some
  1723. 1:04:15combination of these." But I So that's
  1724. 1:04:17the right thing to do. But in terms of
  1725. 1:04:18the pitch, you want to pitch the one
  1726. 1:04:20that's the clear, cleanest story.
  1727. 1:04:23Does that help?
  1728. 1:04:25>> I can answer for them and say yes. Uh I
  1729. 1:04:29hope so.
  1730. 1:04:31If if not then they can say no. Um
  1731. 1:04:35>> yeah uh whoever submitted that one if
  1732. 1:04:37you have any follow-ups please send
  1733. 1:04:39through and in the Q&A. In the meantime
  1734. 1:04:41>> let me ask there's a there's Aman Ray
  1735. 1:04:44has a has his hand up and I want to ask
  1736. 1:04:46him a question because he's one of those
  1737. 1:04:47very good audience members that smiles
  1738. 1:04:49and laughs a lot. So um I I want to
  1739. 1:04:51reward that with a [laughter] with
  1740. 1:04:53asking is a lot of value added as a as a
  1741. 1:04:56lecturer to seeing a sort of an animated
  1742. 1:04:58uh so
  1743. 1:05:00>> Andre you've been called upon.
  1744. 1:05:02>> Yeah. Okay. Uh my question was actually
  1745. 1:05:06so sometimes with these models what
  1746. 1:05:08happens is some of the assumptions they
  1747. 1:05:11may not seem that realistic. For
  1748. 1:05:14example, the hoteling downs model for
  1749. 1:05:17like the one with the median water
  1750. 1:05:19theorem, it assumes full voter turnout,
  1751. 1:05:22right? But empirically that's not well
  1752. 1:05:24observed. I mean empirically we don't
  1753. 1:05:25observe that at all. And yeah, so when
  1754. 1:05:29you relax these assumptions, maybe the
  1755. 1:05:32original model predictions sometimes
  1756. 1:05:34they don't hold up anymore. So what do
  1757. 1:05:37you think of the canonical model in that
  1758. 1:05:39cases like that? like when it's not
  1759. 1:05:41robust to its assumptions being relaxed.
  1760. 1:05:45>> So sometimes so I think it's important
  1761. 1:05:47so I think you should you have to think
  1762. 1:05:48about it. So if that critical assumption
  1763. 1:05:51is changing something that's important
  1764. 1:05:53for explaining the moments in your data
  1765. 1:05:55then then then it's important that you
  1766. 1:05:57actually get that assumption right but
  1767. 1:05:58often it's not right. So often you're
  1768. 1:06:01going to get this convergence result you
  1769. 1:06:03know independently of whether there's
  1770. 1:06:05full turnout or not. So you have to kind
  1771. 1:06:07of decide whether that's important in
  1772. 1:06:08your context but it could be you know
  1773. 1:06:11when I think about it um so for instance
  1774. 1:06:14you know Australia where I'm from you
  1775. 1:06:17know I used to be from so I'm still
  1776. 1:06:18anyway I'm still from there but I don't
  1777. 1:06:20live there. um it has compulsory voting.
  1778. 1:06:25So that element I think so my I guess
  1779. 1:06:29someone else has said it but it's always
  1780. 1:06:30occurred to me in Australia you have
  1781. 1:06:33essentially parties that converge in the
  1782. 1:06:35middle. You don't have any polarization
  1783. 1:06:38because everyone votes. So they're all
  1784. 1:06:40competing for the the median voter and
  1785. 1:06:43it's because that assumption holds by
  1786. 1:06:46institutional construction. If you don't
  1787. 1:06:48vote in Australia you get fined a lot.
  1788. 1:06:49it's compulsory.
  1789. 1:06:51So now what we're seeing, you know, say
  1790. 1:06:54in the US is you're seeing this
  1791. 1:06:55polarization. Well, they're competing
  1792. 1:06:57for those fringe voters. So that's
  1793. 1:06:59clearly a violation of the assumption
  1794. 1:07:01that everyone must vote. But that that
  1795. 1:07:03that is exactly what's generating, I
  1796. 1:07:05think, that polarization because now
  1797. 1:07:07they're not competing over the middle.
  1798. 1:07:08There's more to gain from activating the
  1799. 1:07:10base on either side. So that's that's
  1800. 1:07:12exactly the context. So if I was trying
  1801. 1:07:14to explain Australia, it's not I mean
  1802. 1:07:16some people don't vote. That assumption
  1803. 1:07:18holds. and that generates a result. If
  1804. 1:07:20I'm trying to explain, I can still use a
  1805. 1:07:22lot of the insights of the hoteling
  1806. 1:07:23model in the US context by adding the
  1807. 1:07:28restriction by releasing the restriction
  1808. 1:07:30that people are forced to vote. So, I
  1809. 1:07:31think it just depends on the context and
  1810. 1:07:34and you just have to get some things
  1811. 1:07:36right because they're going to matter
  1812. 1:07:37for the context. Other things you'll get
  1813. 1:07:39wrong, but they don't matter for the
  1814. 1:07:41context. So, you just go with the
  1815. 1:07:43assumption because it's simple and
  1816. 1:07:44parimonious. So you know the bottom line
  1817. 1:07:46is if it's a big moving part in your
  1818. 1:07:48model and it's being generated by an
  1819. 1:07:49unrealistic assumption that's a bad
  1820. 1:07:51model.
  1821. 1:07:55>> Yeah. Thank you.
  1822. 1:07:58>> Perfect. Um we have a couple more hands
  1823. 1:08:00here. So maybe I'll do one more. Sanjo,
  1824. 1:08:02do you want to ask your question
  1825. 1:08:03briefly?
  1826. 1:08:07>> Hey Patrick. Um as a PhD student I I
  1827. 1:08:11just want to say like your lecture was
  1828. 1:08:12absolutely brilliant. uh firstly and I'm
  1829. 1:08:16like sort of in that applied modeling
  1830. 1:08:18process at step two. So I've like
  1831. 1:08:20collected data. I have some predictions,
  1832. 1:08:24correlation, causation, whatever you may
  1833. 1:08:25call it. And now I'm trying to build
  1834. 1:08:27this model. And I think uh this is
  1835. 1:08:30following up on Caleb's question about
  1836. 1:08:33competing canonical models. But the
  1837. 1:08:36struggle that I'm facing is that there's
  1838. 1:08:39no very obvious canonical model in my in
  1839. 1:08:44my case. So for instance, your model is
  1840. 1:08:46a politician identity to citizen or like
  1841. 1:08:48governance outcomes relationship model
  1842. 1:08:52but I'm looking at a bureaucrat identity
  1843. 1:08:54and um governance
  1844. 1:08:58um so I see a bureaucrat as like a
  1845. 1:09:00mechanism from going from the politician
  1846. 1:09:04to the bureaucrat to to governance. So
  1847. 1:09:08in that case, if your if your models to
  1848. 1:09:11choose from are too different from each
  1849. 1:09:12other, like they're not a class. They're
  1850. 1:09:16quite different from each other. Like
  1851. 1:09:18how would you navigate that?
  1852. 1:09:20>> So, so just to be clear, so firstly,
  1853. 1:09:22thanks for saying that. But just to be
  1854. 1:09:25clear, um you have two different models
  1855. 1:09:29that will generate the same
  1856. 1:09:32essentially predictions in your data. Is
  1857. 1:09:34is that that problem? and you're trying
  1858. 1:09:35to distinguish between which one to use
  1859. 1:09:38or is it that you're trying to take
  1860. 1:09:40different components
  1861. 1:09:42from two canonical models and decide how
  1862. 1:09:45to put them together to generate your
  1863. 1:09:49your explanation. I think it's it's the
  1864. 1:09:51latter uh of of having one is an
  1865. 1:09:54asymmetric information model which gives
  1866. 1:09:56you certain kinds of predictions and
  1867. 1:09:58another are these like identity based
  1868. 1:10:00models which give you a certain kind of
  1869. 1:10:03prediction and you're trying to you feel
  1870. 1:10:05from your empirical predictions that
  1871. 1:10:06these moving parts matter
  1872. 1:10:09>> u but how do you how do you bring that
  1873. 1:10:12together and like sort of like construct
  1874. 1:10:14it? Yeah.
  1875. 1:10:15>> Yeah. So those two, if I understand
  1876. 1:10:17them, those two um components are not at
  1877. 1:10:20odds. They could be built into one model
  1878. 1:10:22and they could have both moving parts.
  1879. 1:10:25And that's actually better, right?
  1880. 1:10:27Because then you're contributing by, you
  1881. 1:10:30know, amalgamating two freestanding
  1882. 1:10:32models into one framework and generating
  1883. 1:10:35predictions that are coming from
  1884. 1:10:37different components of that framework.
  1885. 1:10:39So you need them both to explain your
  1886. 1:10:41data. I think that's a a good thing.
  1887. 1:10:43That's a kind of a a richness. So it's
  1888. 1:10:45saying look I can't and this is a good
  1889. 1:10:47thing to do like especially you know
  1890. 1:10:49we've all been in talks where somebody
  1891. 1:10:51says now I'm going to give you the model
  1892. 1:10:52and you just see you know pages of math
  1893. 1:10:54and you're like oh my god you know so
  1894. 1:10:57here's a motivation for people to do the
  1895. 1:10:59work because you go look you you have
  1896. 1:11:00this one model in mind that doesn't do
  1897. 1:11:02the work and this other model which you
  1898. 1:11:04also have doesn't but when I put them
  1899. 1:11:05together and I have to do a bit of work
  1900. 1:11:06to do that but when I put them together
  1901. 1:11:08it's going to give us so much more
  1902. 1:11:10richness
  1903. 1:11:11so it motivates the modeling the model
  1904. 1:11:14building process because neither one can
  1905. 1:11:16is sufficient to to explain the data
  1906. 1:11:18that you have. So to me, that's a good
  1907. 1:11:20thing. It's not a I don't see an
  1908. 1:11:21inherent tension in that. Where there's
  1909. 1:11:23a tension is when they're they're
  1910. 1:11:25actually at odds and you can't build the
  1911. 1:11:26model because they actually have two
  1912. 1:11:27very different moving parts. Then you
  1913. 1:11:29kind of have to go with one or the other
  1914. 1:11:30and then the data should tell you which
  1915. 1:11:31one's doing better. Um so yeah, so I
  1916. 1:11:35think that's the I think it's okay. I
  1917. 1:11:37think that's not a huge problem. I think
  1918. 1:11:38it's good. I think you should explore
  1919. 1:11:40that richer model because you need it
  1920. 1:11:41for the data. Um,
  1921. 1:11:45>> thank you.
  1922. 1:11:48>> Thanks, Sanjanna. I I think that uh I've
  1923. 1:11:50certainly also seen papers where
  1924. 1:11:52complementing models built on top of
  1925. 1:11:55each other do provide more of a
  1926. 1:11:57richness. Um, but there is another side
  1927. 1:12:01and someone else has asked about this
  1928. 1:12:03whether we we were talking about
  1929. 1:12:05layering models. Now
  1930. 1:12:08Patrick, do you think that having an
  1931. 1:12:09explicit model always improves a
  1932. 1:12:12political economy paper or are there
  1933. 1:12:14cases where a plain English explanation
  1934. 1:12:16is actually superior? Maybe you can draw
  1935. 1:12:19on experiences both, you know, as a
  1936. 1:12:21model and a consumer of research.
  1937. 1:12:23>> Yeah. Yeah. No, great great um question.
  1938. 1:12:26So uh if you can do it all in English,
  1939. 1:12:30do it in English. So, I just don't think
  1940. 1:12:34there's any point to putting in math
  1941. 1:12:36something that just repeats and
  1942. 1:12:38regurgitates the basic intuition that
  1943. 1:12:41you already have in English. So, so I
  1944. 1:12:43think a lot of papers just are fine to
  1945. 1:12:47be just done as essentially it's it's an
  1946. 1:12:50empirical result and here's the you
  1947. 1:12:53already have implicitly in your mind
  1948. 1:12:55probably what's going on and I'm going
  1949. 1:12:57to tell you in English and that's fine.
  1950. 1:12:58you don't even need the um the the
  1951. 1:13:01theoretical model. So I think that's
  1952. 1:13:03fine. Yeah. So often it is just the
  1953. 1:13:05case. So I think when you're going to
  1954. 1:13:07drag somebody through your formalization
  1955. 1:13:10and a bunch of results,
  1956. 1:13:13it has to be doing some work. So So by
  1957. 1:13:16work I mean the distance between the
  1958. 1:13:19assumptions and the results. I mean I
  1959. 1:13:21used to have a uh a uh he was actually
  1960. 1:13:26one of my supervisors Mckesh Ezarn and
  1961. 1:13:29he used to say there has to be a
  1962. 1:13:30gentlemanly distance between assumption
  1963. 1:13:32and results. It means it just can't be
  1964. 1:13:35that you know you're essentially just
  1965. 1:13:36regurgitating your assumptions in your
  1966. 1:13:38results. If if the model isn't
  1967. 1:13:42generating
  1968. 1:13:44insight. So what it means is when you
  1969. 1:13:46throw these assumptions together, how
  1970. 1:13:48come this result how come you get this
  1971. 1:13:50result if that's if that's completely
  1972. 1:13:52obvious you don't need to build the
  1973. 1:13:53model probably you can just tell the
  1974. 1:13:54story. If it's not obvious then you know
  1975. 1:13:57they need to go through well here's
  1976. 1:13:58here's the theorem here's here's how it
  1977. 1:14:00holds together here are the conditions
  1978. 1:14:03under which the theorem holds and that
  1979. 1:14:04wasn't obvious and here's the extra
  1980. 1:14:06prediction that wasn't obvious. All that
  1981. 1:14:07stuff has to be non-obvious.
  1982. 1:14:09I mean that's why you're dragging people
  1983. 1:14:11through reading all your math. I mean we
  1984. 1:14:13don't very few of us think in math right
  1985. 1:14:15we mostly think in just narrative so
  1986. 1:14:18whatever language it is English is the
  1987. 1:14:20one we tend to write in so we just tell
  1988. 1:14:21it in English I don't think you need a
  1989. 1:14:23model for a lot of a lot of applications
  1990. 1:14:28>> thank you um
  1991. 1:14:32we'll go now to back to our kind of live
  1992. 1:14:34panelists here Gagas would you like to
  1993. 1:14:44You're muted mute there.
  1994. 1:14:48>> All right. Thank you. Can you hear me
  1995. 1:14:49now?
  1996. 1:14:50>> Yes.
  1997. 1:14:51>> Okay. Thank you so much for the
  1998. 1:14:53beautiful presentation. I have a couple
  1999. 1:14:55of questions anyway, but let me just
  2000. 1:14:56push one for now. Um so you you talked
  2001. 1:15:00about um the possibility of having um an
  2002. 1:15:04amazing model so to say in a class of
  2003. 1:15:07competing models right that could also
  2004. 1:15:10pro provide you with the best result.
  2005. 1:15:12But my question is what then happens in
  2006. 1:15:14an instance whereby you pick a model
  2007. 1:15:16which as far as you are concerned is the
  2008. 1:15:18best model in that class of rival
  2009. 1:15:20alternatives and yet you are having a
  2010. 1:15:22challenge of fitting it into reality or
  2011. 1:15:26reality into it. Okay, especially in the
  2012. 1:15:30context of political economy where the
  2013. 1:15:32data itself could be political. It is
  2014. 1:15:34only as good as the political class
  2015. 1:15:36tells you it is. I'm saying this um with
  2016. 1:15:40a particular emphasis on where I'm
  2017. 1:15:41coming from Africa for example that data
  2018. 1:15:44may have integrity issues. So I'm asking
  2019. 1:15:47what happens where your model is as far
  2020. 1:15:50as you are concerned good the best
  2021. 1:15:52perhaps but then there are issues with
  2022. 1:15:54fitting it into reality or fitting
  2023. 1:15:56reality into it and then how do I avoid
  2024. 1:15:58the tragedy of forcing your model to
  2025. 1:16:01confess the reality it was not built to
  2026. 1:16:04to you know mirror and all of that. I'll
  2027. 1:16:07be glad if you can assist. Thank you.
  2028. 1:16:10>> Okay, good question. So, so that that um
  2029. 1:16:13world in which I have my model that I
  2030. 1:16:17think is a beautiful model and that I
  2031. 1:16:19think fits and explains the world,
  2032. 1:16:22but reality is getting in the way and
  2033. 1:16:26saying, "Yeah, that model's not right."
  2034. 1:16:27That's that's a world that I've lived in
  2035. 1:16:29a lot. Um where I built complicated
  2036. 1:16:32models and thought, "Yeah, these are
  2037. 1:16:33this is such a cool model. So subtle.
  2038. 1:16:37But that's useless. So you know if if so
  2039. 1:16:41one part of it one way to think of it is
  2040. 1:16:43if really reality just keeps saying no
  2041. 1:16:46that just fails that just model isn't
  2042. 1:16:48working then you just have to throw that
  2043. 1:16:50model out even though it might be the
  2044. 1:16:51most beautiful thing because I mean
  2045. 1:16:52ultimately we're not artists right we're
  2046. 1:16:55we're trying to explain the world
  2047. 1:16:57but so so if at that level of your
  2048. 1:17:00question I think yeah it's awful the you
  2049. 1:17:04know our models don't always work and I
  2050. 1:17:07wish the world was better but it's not
  2051. 1:17:08so you We're not mathematicians. When we
  2052. 1:17:10if we were, we'd be terrible
  2053. 1:17:11mathematicians. So, we're we're trying
  2054. 1:17:13to explain the world and if the world
  2055. 1:17:15keeps saying this isn't fitting, you
  2056. 1:17:16just got to throw it out. You got to
  2057. 1:17:18live with it. But I think you said
  2058. 1:17:20something else too, which is kind of a
  2059. 1:17:21like a I think another issue, which is
  2060. 1:17:23that if you really doubt the the
  2061. 1:17:26veracity of the data, and in some
  2062. 1:17:28context you are going to doubt it, then
  2063. 1:17:30maybe that's not the right metric you
  2064. 1:17:32should be using for your model. So, you
  2065. 1:17:34might say, look, you know, my model's
  2066. 1:17:36not fitting. Um, I think it's what's
  2067. 1:17:39going on and I have these other maybe
  2068. 1:17:41stylized facts that make me think this
  2069. 1:17:43is actually really true and important.
  2070. 1:17:44The data is is rejecting it, but I have
  2071. 1:17:47reasons to believe [snorts] that that
  2072. 1:17:49data is incorrect. So, so then you're
  2073. 1:17:53questioning the data, right? You're
  2074. 1:17:55questioning then what are you
  2075. 1:17:56questioning then? You're you're
  2076. 1:17:57questioning our our empirical picture,
  2077. 1:17:59our picture of, you know, the the
  2078. 1:18:01reality. Now, that's a different issue.
  2079. 1:18:04Like if if you have deep reasons and
  2080. 1:18:06good reasons to to doubt the the
  2081. 1:18:09veracity of the picture you're getting
  2082. 1:18:10from the data then you shouldn't be
  2083. 1:18:12trying to match that data. So so I think
  2084. 1:18:15I think but but what would what I would
  2085. 1:18:17resist you know exant is just building a
  2086. 1:18:21model it doesn't fit the data and then
  2087. 1:18:24saying oh that's because you know now I
  2088. 1:18:25want to say the data is bad. So you have
  2089. 1:18:27to be careful right? So because you can
  2090. 1:18:28always just say look I'm not going to
  2091. 1:18:30you know that thing that I'm seeing
  2092. 1:18:32outside the window that didn't happen
  2093. 1:18:34right and you know so you have to resist
  2094. 1:18:36that. So but yeah um some data is very
  2095. 1:18:40reliable right so that's the ones and
  2096. 1:18:42some some isn't and then you know you're
  2097. 1:18:44right you got a problem and you know
  2098. 1:18:45this is we don't usually go there in
  2099. 1:18:47economics too much right so we usually
  2100. 1:18:49but you know there's a there's a kind of
  2101. 1:18:50a more profound critique which is like
  2102. 1:18:52the post structural postmodern critiques
  2103. 1:18:55which is that all data is generated all
  2104. 1:18:57data is you know they put a lot of they
  2105. 1:18:59think we're very naive in the way that
  2106. 1:19:01we view the world and and partly that
  2107. 1:19:03there's a truth to that like a lot of
  2108. 1:19:04this is a postcolonial literature
  2109. 1:19:06saying, you know, the data was created
  2110. 1:19:08by the victors and tells a narrative and
  2111. 1:19:11that narrative is one that's in the
  2112. 1:19:13favor of a particular class of people or
  2113. 1:19:15something like that. So, we don't
  2114. 1:19:17usually do those post post type uh
  2115. 1:19:20critiques in economics, but I think
  2116. 1:19:22there's a there's something to that and
  2117. 1:19:24in some context there really is
  2118. 1:19:25something to that. So, you know,
  2119. 1:19:26sometimes the data can be dodgy. Yeah.
  2120. 1:19:30>> Thank you, sir.
  2121. 1:19:32>> You're welcome.
  2122. 1:19:33>> Thank you, Carass. Um, we'll go back now
  2123. 1:19:36to the chat and there there are a couple
  2124. 1:19:38questions about counterfactuals.
  2125. 1:19:41Um, I'll read one. It says, "In
  2126. 1:19:43structural political economy, how do you
  2127. 1:19:45prevent overspecifying candidate
  2128. 1:19:47mechanisms when structural
  2129. 1:19:48counterfactuals heavily depend on
  2130. 1:19:50institutional primitives that remain
  2131. 1:19:52unobservable or underidentified in
  2132. 1:19:54baseline empirical facts?"
  2133. 1:19:56>> Yeah, that's a good question. Yeah. So,
  2134. 1:19:58um, so, so I think there's two things
  2135. 1:20:00here. So one is um
  2136. 1:20:04yeah when they're unobservable you know
  2137. 1:20:07we're really in the realm of you know
  2138. 1:20:08you have to try to convince people that
  2139. 1:20:10you know when when I'm doing this
  2140. 1:20:11counterfactual that those primitives are
  2141. 1:20:13not going to change and you know how do
  2142. 1:20:15you do that um
  2143. 1:20:18various ways I mean you could maybe
  2144. 1:20:20point to other contexts where they were
  2145. 1:20:22relatively invariant across such a
  2146. 1:20:24change that would be one way to do it
  2147. 1:20:25but you know it's not always going to be
  2148. 1:20:26available so there may be ways of
  2149. 1:20:29convincing people by pointing to
  2150. 1:20:30analogist situations
  2151. 1:20:33often there isn't and then it's just
  2152. 1:20:34going to come down to people you know I
  2153. 1:20:37you see it and people are often too
  2154. 1:20:38polite to say in the seminar but they're
  2155. 1:20:40like uh you know come on like you know
  2156. 1:20:42under that counterfactual everything
  2157. 1:20:44everything would change it's like you
  2158. 1:20:46can't hold x fixed you know whatever it
  2159. 1:20:49is whatever the parameters fixed theta
  2160. 1:20:52so you know that it's just it's just
  2161. 1:20:54it's there's no kind of clear formula
  2162. 1:20:56for that you know it's in a sense we're
  2163. 1:20:57trying to it's we're running narratives
  2164. 1:20:59and we're trying to convince convince
  2165. 1:21:00others that this is a sensible thing to
  2166. 1:21:01do. [sighs]
  2167. 1:21:03Um the question of overfitting I think
  2168. 1:21:06is a slightly different one in the sense
  2169. 1:21:08that you know uh when you're I mean I
  2170. 1:21:12think this is one of the advantages of
  2171. 1:21:13of doing structural work is when you
  2172. 1:21:16have a a a structural framework you
  2173. 1:21:20actually have your model you have your
  2174. 1:21:23set of parameters you have your
  2175. 1:21:24estimates and you fit the data however
  2176. 1:21:28you fit it. Now you know I I know I can
  2177. 1:21:32always write down a model with more
  2178. 1:21:33parameters, more moving parts that will
  2179. 1:21:35fit better. I know I can do that. Now
  2180. 1:21:40how do you compete? How do you test
  2181. 1:21:42between those models? So there are tests
  2182. 1:21:43that actually do penalize overfitting.
  2183. 1:21:46So we can formally do that. So that's
  2184. 1:21:49that's uh
  2185. 1:21:51one way one way that we do it. Now it
  2186. 1:21:54depends on your context, right?
  2187. 1:21:55sometimes just fitting is what you want
  2188. 1:21:57to do and then you don't even care about
  2189. 1:21:59the economic narrative right so if
  2190. 1:22:01you're you know LLM are essentially
  2191. 1:22:03doing that they have you know a
  2192. 1:22:04gazillion which is where gazillion is a
  2193. 1:22:06large number of parameters that they
  2194. 1:22:08estimate on a on a on a on a very big
  2195. 1:22:10data set and it allows them to predict
  2196. 1:22:13now do we understand no we don't
  2197. 1:22:15understand how it's doing it I it's
  2198. 1:22:17totally a mystery how they can provide
  2199. 1:22:19such coherent answers to things but it
  2200. 1:22:21is just a big structural estimation
  2201. 1:22:24problem on a lot of data and that in
  2202. 1:22:27that context that's the right thing to
  2203. 1:22:29do right in economics context we don't
  2204. 1:22:31usually want that what we want is to
  2205. 1:22:34provide a narrative an explanation for
  2206. 1:22:36the observables and generally we want to
  2207. 1:22:40not have a blackbox explanation so so
  2208. 1:22:43but but in the set of explanations that
  2209. 1:22:45are not blackbox we can have two that
  2210. 1:22:47would rationalize you know not
  2211. 1:22:49rationalize in in a structural setting
  2212. 1:22:50we're matching we're fitting the data
  2213. 1:22:52the one with more parameters will often
  2214. 1:22:53fit better, but you know, it's coming at
  2215. 1:22:55the cost of more parameters and we have
  2216. 1:22:56tests to to trade these off. So, I think
  2217. 1:22:58it's a combination of this story is a
  2218. 1:23:00good story. It fits the data pretty
  2219. 1:23:03well. It explains things pretty well. It
  2220. 1:23:04doesn't seem like it's overfitted. You
  2221. 1:23:06know, it's kind of more of a handwavy
  2222. 1:23:08type thing, you know. Um, yeah,
  2223. 1:23:12elements of science, elements of art
  2224. 1:23:14there,
  2225. 1:23:15>> art and science together.
  2226. 1:23:17>> Um,
  2227. 1:23:18>> Zoo, uh, over to you. Do you want to ask
  2228. 1:23:21your question?
  2229. 1:23:22>> Yeah. Uh can you hear me? Um thank you
  2230. 1:23:25uh Professor Francois. Uh kind of a big
  2231. 1:23:27picture question. Uh where do you see
  2232. 1:23:29the role of applied political economy
  2233. 1:23:32modeling in development and political
  2234. 1:23:34economy in the future given that there
  2235. 1:23:36was a trend in development economics
  2236. 1:23:38credibility revolution that there's a
  2237. 1:23:40lot of kind of replete with empirical
  2238. 1:23:42facts and a lot of improvement in
  2239. 1:23:45identification of those empirical facts.
  2240. 1:23:46Do you see the same trend that um we're
  2241. 1:23:50moving towards you know identifying
  2242. 1:23:52mechanisms to applied modeling and uh
  2243. 1:23:55second part of that is what advice
  2244. 1:23:57particular advice would you give to kind
  2245. 1:24:00of young researchers who try to navigate
  2246. 1:24:02that landscape?
  2247. 1:24:04>> Yeah, it's tough. So, so I think I I you
  2248. 1:24:07know I think so I I primarily see myself
  2249. 1:24:10as a development economist. That's what
  2250. 1:24:12I'm interested in. That's what I've
  2251. 1:24:14always liked. And I moved into political
  2252. 1:24:16economy um because I felt like the
  2253. 1:24:19questions that I wanted to understand
  2254. 1:24:21weren't really being tackled in in
  2255. 1:24:23development. And partly it's because um
  2256. 1:24:26it became so a theoretical. I was always
  2257. 1:24:29interested in mechanisms like why is
  2258. 1:24:30there so much variation in development?
  2259. 1:24:32Why do we see these big differences? And
  2260. 1:24:34the questions that they're very hard to
  2261. 1:24:37to answer because it's very hard to
  2262. 1:24:39identify a particular mechanism. So you
  2263. 1:24:42never fully identify things very well
  2264. 1:24:44unless you can actually control the
  2265. 1:24:45variation. So I think development got
  2266. 1:24:48very obsessed with and in a good way,
  2267. 1:24:50right? It got obsessed with trying to
  2268. 1:24:53say things that were true, trying to
  2269. 1:24:55identify causal relationships. That was
  2270. 1:24:58a good thing because again, when I was
  2271. 1:25:00in grad school, people were just
  2272. 1:25:02regressing indogenous things on each
  2273. 1:25:03other all the time and it was very
  2274. 1:25:05sloppy. So it needed it, right? Um,
  2275. 1:25:09but I feel like to me that's a kind of
  2276. 1:25:11a,
  2277. 1:25:13you know, I mean, I think it's it's not
  2278. 1:25:15unreasonable for people to say, why
  2279. 1:25:17isn't anyone doing development anymore?
  2280. 1:25:19Like, why isn't anyone asking the big
  2281. 1:25:20questions? Why is everyone just finding
  2282. 1:25:22out very specific bits of information
  2283. 1:25:24about things that will work in
  2284. 1:25:26particular contexts? And and I think
  2285. 1:25:29that, yeah, that's a reasonable
  2286. 1:25:30question. So, I I I don't I'm not very
  2287. 1:25:32good at predicting the future. I I don't
  2288. 1:25:34think political economy is going to go
  2289. 1:25:36there. I think the best to me the best
  2290. 1:25:39case scenario is people are asking
  2291. 1:25:41questions that are big thinking about
  2292. 1:25:44with theory usually because it's just
  2293. 1:25:46too hard to do without it. Thinking
  2294. 1:25:48about like the the things I should be
  2295. 1:25:49able to run in my experiments that will
  2296. 1:25:51help me identify those bigger questions.
  2297. 1:25:54So so it's a combination of both. I
  2298. 1:25:56don't I see and so to answer your
  2299. 1:25:58question I think for a student I think
  2300. 1:26:01we teach people how to solve complicated
  2301. 1:26:04models very well in grad school we do
  2302. 1:26:06complicate and we actually select for
  2303. 1:26:08math mathiness in that sense but I don't
  2304. 1:26:11think we teach people very well how to
  2305. 1:26:13build models and I feel like there's a
  2306. 1:26:17lot of value added to doing a little bit
  2307. 1:26:19of that model building in the empirical
  2308. 1:26:22project. So as a grad student, I would
  2309. 1:26:24invest a bit of time in that which is in
  2310. 1:26:26the political economy realm. To me, it's
  2311. 1:26:27understanding those canonical models,
  2312. 1:26:29having them in the back of my mind.
  2313. 1:26:30That's the advice I would that's the
  2314. 1:26:32advice I do give and I I would give and
  2315. 1:26:34I teach this course. I teach like a
  2316. 1:26:3612-week course on how to build models in
  2317. 1:26:38political economy. That's what I do
  2318. 1:26:39because I think it's a useful thing.
  2319. 1:26:40It's a complement to your core and it's
  2320. 1:26:43still your core business which is the
  2321. 1:26:44empirical one.
  2322. 1:26:48>> Thank you very much, professor.
  2323. 1:26:50>> Yeah, no worries. Thank you. It is
  2324. 1:26:52pretty incredible um just everyone
  2325. 1:26:54that's here how condensed
  2326. 1:26:58uh the professors are making what is
  2327. 1:27:02normally maybe a semester long class
  2328. 1:27:04into an hour hour and a half uh every
  2329. 1:27:08week. And so um we we recognize there is
  2330. 1:27:11a lot of of information but it's
  2331. 1:27:15something that you'll be able to
  2332. 1:27:16reference back to and and build on. Um,
  2333. 1:27:20I think that this is really the that's
  2334. 1:27:22kind of the zoomed out perfect place to
  2335. 1:27:24to end the lecture. And I just really
  2336. 1:27:27want to thank Professor Vansis for your
  2337. 1:27:30time and um your your insights.
  2338. 1:27:34Everyone, I've I've put in just a couple
  2339. 1:27:37of things into the chat um for links
  2340. 1:27:40that that you should reference, but but
  2341. 1:27:42really thank you for coming. Uh we we
  2342. 1:27:45look forward to to you joining us next
  2343. 1:27:48week with Professor Tim Bezley u to talk
  2344. 1:27:52about state capacity and we uh look
  2345. 1:27:55forward to seeing you then.
  2346. 1:27:56>> Thank thank you too for um letting me do
  2347. 1:27:59this and I I enjoyed it a lot. I think
  2348. 1:28:01the questions were great and I think
  2349. 1:28:03this is a really good initiative too
  2350. 1:28:04just to get a a view of how all of us
  2351. 1:28:07approach this a little bit differently
  2352. 1:28:09and you should definitely go to Tim's
  2353. 1:28:10talk. Tim is one of the great applied
  2354. 1:28:13modelers, right? So, he is does exactly
  2355. 1:28:16this, I think. Um, and he also, you
  2356. 1:28:18know, he's just great. So, you should
  2357. 1:28:20come to it and enjoy it. You'll learn a
  2358. 1:28:22lot.
  2359. 1:28:23>> Well, we have a personal endorsement
  2360. 1:28:25here, guys. So, so we'll very much uh
  2361. 1:28:28hope to see you next week. Thank you
  2362. 1:28:29again, Patrick, and hope everyone has a
  2363. 1:28:31great rest of your days.
  2364. 1:28:32>> Thank and thank you, Caleb. You did a
  2365. 1:28:34great job.
  2366. 1:28:35>> Thank you.
  2367. 1:28:36>> Was excellent lecture. Thank you.
  2368. 1:28:38>> Thank you.
  2369. 1:28:38>> Thank you. Thank you.

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