Tag Archives: natural experiment

Fresh Economics History

This term I'm taking "International Economics History" - although there is the word "international economics" in the title of the course, actually it is all about growth. Remember last time when I went to  Barcelona GSE “Trobada” VIII, the teacher, Davide Cantoni, stands out among all speakers... so impressed! Well, now I can say that I have waited for this course for half a year, haha!

Yesterday I also went to his seminar (partly for the free sandwich~), it was

Date: 06/04/2011
Speaker: Davide Cantoni (UPF)
Title: Clueless? The Impact of Television on Consumption Behavior (with Leo Bursztyn)

as well as another following seminar on economics history today

Date: 07/04/2011
Speaker: James Fenske (Oxford)
Title: Ecology, trade and states in pre-colonial Africa

From this two seminars, I can feel that a fresh trend of econometrics-based economics history is blooming. Recall that this year's job market star from UPF, Peter Koudijs, who writes a paper "The Boats that did not sail. News, Trading and Asset Price Volatility in a Natural Experiment", is focusing on analyze and provide insights of modern economic research from the historical view. I think that is how people should (re)define economics history now. The traditional economics history, e.g. what I learned in China at the undergraduate level, is all about how the economic theories evolve. From the ancestor Adam Smith, to the recent mainstream guys, that's what the course can tell me. In contrast, the economics history course I'm learning now is all about how to support your theory from the historical view - which reminds me the famous Chinese saying that “History is a mirror that reflects the vicissitude of life (以史为镜,可以知兴替)”。BTW, I'm a kind of feeling now that China can really draw people's eyeballs. Today in another class, the professor quoted Confucius'

By three methods we may learn wisdom:  First, by reflection, which is noblest; Second, by imitation, which is easiest; and third by experience, which is the bitterest.

Well, I really need to search for it...and it turns out to be


Oh well... OK, if it means that.... I'm pretty confused now.

Davide Canton's speech was about an natural experiment, the reunion of west and east Germany, and its influence on television signals. Pretty interesting idea and nice paper. On the other hand, James Fenske shows me how to utilize the modern econometrics methods with historical evidence and from then on, how can it provide insights to those unclear questions in economic theories. Notable, he is such a careful research! Have a look at his robustness check part - so impressive!

By three methods we may learn wisdom:
First, by reflection, which is noblest;
Second, by imitation, which is easiest; and
third by experience, which is the bitterest.

Natural experiment on public good and social behaviors

Today, suddenly I saw the latest issue of AER (SEP, 2010. How late I was!). I failed to stop myself from having a look at it, although it is already in the exam weeks. After a balance, I chose to have a brief look at this issue. It is a kind of evidence that my life has become worse - I used to at least read the content of every issue of AER, JPE, QJE every season... Now it has been such a long time that I have no access to these journals. I cannot stop myself, and I was so excited when I saw the red face of AER again. (I was also overexcited when I heard the news that LYX 2.0 is going to be released. Fantastic new features: Advanced Search, Spell-checking on the fly, Multilingual Thesaurus, Table features, Progress view and debugging pane, Instant preview inset, etc!!! Awesome! For details, just jump to http://wiki.lyx.org/LyX/NewInLyX20)

OK. Go back to AER. Two articles attracted my interests:

First one first. The first reason why I was attracted because of the words "social" "contribution" "online communities" and "field experiment". Without doubt, it reminded me of Michael Zhang's paper immediately (also, here is a brief intro in Chinese I wrote before).

Then the author. The world is so small. I just met Sherry Xin Li this spring when I was spending a month auditing courses and seminars in Tsinghua and Peking U. Her topic was "虚拟世界实验中的社会距离问题", or "Social Distance in a Virtual World Experiment". It was an interesting paper about experiments they did in the virtual world game "Second Life". Thus, it is interesting for me to see her work again, since the online market is always a market I'm paying attention to.

In this paper, she/they designed several experiments to study how the social comparison increases contributions to an online community. Here are some main results:

  • After receiving behavioral information about the median user’s total number of movie ratings, users below the median demonstrate a 530% increase in the number of monthly movie ratings, while those above the median do not necessarily decrease their ratings.
  • When given outcome information about the average user’s net benefit score, above-average users mainly engage in activities that help others.
  • Effective personalized social information can increase the level of public goods provision.

Public good is always an interesting topic for economists, perhaps due to the fact that market inefficiency/failure has always been concerned by economists.  Now I'm interested in the social behaviors. Can we actually design a mechanism to improve the supply of public goods? What are the necessary conditions for those mechanisms to function well?

Moreover, another interesting point is that how to utilize the data from the Internet. Frank has a good comment on it. I'm learning from more and more published papers to see where are the pitfalls.

OK, go to the second paper. The law of the few stresses an empirical phenomenon: in social groups a very small subset of individuals invests in collecting information while the rest of the group invests in forming connections with this select few. The interesting thing here is that someone prefer to invest in information while the rest invest in forming connections (Which type I am? Both???Haha~)

It is a kind of traditional social network application, and a little old (the working paper version I found was written in 2007, now it is 2010! what a long publishing cycle!). The authors talked about the structure of social network, and of course, network game. The meaningful suggestion for policy makers (either government or advertisement makers) is that

by collecting information about the communication network, for example by asking a subset of the community members to report “with whom they talk to” about a particular matter, the government can identify an opinion leader, the individual who receives most nominations. Each dollar spent on this opinion leader will then spill over to all community members.

Which have been confirmed by some of my friends who are using similar strategies in their broadcastings.

Fine... I'm thinking about my master project now so everything I'm caring about is how to apply social network to a certain field. Hopefully I can find some interesting points a few days later. But anyway, I need to pay attention to the exams. Go back to books and problems.

Back from Barcelona GSE "Trobada" VIII

I have no idea with what "trobada" means, and apparently it is not a spanish word. Yes, it is from Catalan and it means "conference"..... So Barcelona GSE "Trobada" VIII is the annual conference for GSE afflicted professors.

This year it is held in a very beautiful and historical building, Casa Convalescència. Oh, I admit I should have brought my camera there. What a pity! I can only download some pictures from the Internet and paste them here.

Casa Convalescència


Today's topics were very interesting. I listened to three presentations.

Prof. Giacomo Ponzetto (CREI-UPF and Barcelona GSE)
"Politics, Asymmetric Information, and Protectionism"

Prof. Johannes Gierlinger (UAB and Barcelona GSE)
"Hedging Priors: On Novel Instruments to Insure against Ambiguity"

Prof. Davide Cantoni (UPF and Barcelona GSE)
"Natural Experiments in Economic History"

I was there because  the last one, natural experiments in economic history, attracted me. It was a very brilliant idea to "design" natural experiment in economic history. Well, one interesting thing is that nearly all people admit that we need to learn economic history, but this course is still not available here (sorry, it is available. I made a mistake), and not many students will actually registered for it, perhaps due to the way it is taught and the form of exam.

Another thing I was considering for the whole morning was that what's the difference between the questions European economists care about and those from U.S. or China. In China we don't need to think about "lobby", since the political system is so different. If institution plays an important role in determining the economic growth speed and pattern, what can we conclude from China's example?  Is the potential lobby power (like the pressure from big companies) growing and influencing policy makers? Will they still consider the global situation and make a wise choice?

A big problem for China now may be the exchange rate. G20 Conference is holding, and everyone is predicting the trend of future's world economy. I have heard that whenever the Chinese department of commerce is going to make a new economic policy, they will face different pressure from all related industries. Therefore, can they still stay balanced and choose the best strategy for the whole economy? It is definitely hard, and we cannot forecast the result. Economic models cannot tell everything in the real world. We can learn from economic theories, or the real history.

[Update 2010.10.24]

1. Thanks for Jodi's email, and now I update the new pictures. For more, see http://www.flickr.com/photos/barcelonagse/sets/72157625216250106/

2. I emailed Prof. Davide Cantoni and got the list of papers he mentioned on the conference (He is really a nice guy, and I do want to take his economic history course now). I'd like to paste the list here, and so, enjoy~~~

Acemoglu, Johnson, Robinson, "Colonial Origins of Comparative Development" (http://ideas.repec.org/a/aea/aecrev/v91y2001i5p1369-1401.html)

Jeremiah Dittmar, "Information Technology and Economic Change: The Impact of the Printing Press" (http://www.jeremiahdittmar.com/research)

James Feyrer and Bruce Sacerdote, "Colonialism and Modern Income: Islands as Natural Experiments" (http://ideas.repec.org/a/tpr/restat/v91y2009i2p245-262.html


Elise Huillery, "History Matters: The Long Term Impact of Colonial Public Investments in French West Africa" (http://econ.sciences-po.fr/elise-huillery/papers)

Melissa Dell "The Persistent Effects of Peru's Mining Mita" (http://econ-www.mit.edu/grad/mdell/papers)

A paper that gives a good review on this strand of research more generally is Nathan Nunn's contribution to the "Annual Review":