Category Archives: economics

Labor Market Dynamics, Persuasion

As the final exams coming, the time-budget has been more and more tight for me. I really want to go to the seminars, but there is not enough time for me to do that -- I always feel so tired....

Anyway, last Friday there was a workshop I cannot miss:

CREI-CEPR Workshop "Changes in Labor Market Dynamics"

Because Jordi Galí and Thijs van Rens, CREI and CEPR organized it.....And I'm really interested in labor market.

I listened to the first three speeches,

Demand Shocks Trigger Productivity Increases
Yan Bai, Arizona State University | W.P. Carey S. of Business, *José Víctor Ríos Rull, University of Minnesota, Kjetil Storesletten, Federal Reserve Bank of Minneapolis

The Vanishing Procyclicality of Labor Productivity
Jordi Galí, CREI, UPF & Barcelona GSE, Thijs van Rens, CREI & UPF

The Demise of Okun’s Law and of Procyclical Fluctuations in Conventional and Unconventional Measures of Productivity
Robert Gordon, Northwestern University

Eh..... Maybe due to the limit of time, they only introduced their works briefly. The problem for me is that I learned more labor related topics in a microeconomic view, not the macro one. Therefore, although the presentations were talking about labor, I still felt unfamiliar. Anyway, listening is a kind of learning and enjoying. Why not?
This afternoon was the regular microeconomics seminar, and it was

Bayesian Persuasion and Competition and Persuasion
[click here to download PDF]
Emir Kamenica (Chicago Booth School of Business)
CREI-CEPR Workshop "Changes in Labor Market Dynamics"

UPF Microeconomics Seminar

Again, I failed to catch up with all of his content. I was enjoying the first 1/3 part of his presentation, and then suddenly I realized that I cannot understand him any more. Haha... The interesting thing was not only me, but also most of the audience in the room kept silent. Nearly no questions, no discussions and answer when the speaker asked something. Haha~ Anyway, perhaps the difference between economics and business are still big, so we don't really understand what's their aim. Or the models are quite different.... I cannot find any more possible explanations. Forgive me!

Ok, this post has successfully become a normal record of my day. I don't really want to lost my feeling for economics, but the problem sets....are still there. No choice.

Social learning and dynamic pricing

Ohhhhhhh, this week I was too busy to listen to the seminars. Fortunately, on Thursday I finally got a little time to audit a speech by a Chinese guy from Upenn. Haha~ It is not common to see any other Chinese here.

However, I came there because of the topic, not his name or something else. I was attracted by his title at the first glance, since I really would like to know something about social learning. That's a pretty interesting issue to talk, and requires enough mathematical skills. So....the related information first, as usual:

Dynamic Pricing in the Presence of Social Learning
Xi Weng (University of Pennsylvania)

UPF Internal Micro and Behavioral Economics Seminar

and here is the abstract attached:

This paper considers a monopolist selling a new experience good over time to many buyers.
Buyers learn from their own private experiences (individual learning) as well as by observing other buyers' experiences (social learning). Individual learning generates ex post heterogeneity, which affects the buyers' purchasing decisions and the firm's pricing strategy. When learning is through good news signals, the incentive to exploit the known buyers for the monopolist causes experimentation to be terminated too early. After the arrival of a good news signal, the price could instantaneously go down in order induce the remaining unknown buyer to experiment. When learning is through bad news signals, experimentation is effcient, since only the homogeneous unknown buyers purchase the experience good.

Enough background. I am interested in social learning because it considers a dynamic process of the production delivering process. Such as Ipod and some other fashion products sold in the market, there must be some "loyal" fans who would like to try and share their experience firstly, and then more and more potential consumers will do the purchase in turn.

Eh.... Nothing more to say? Maybe there are too many math formulas which makes me confused......Anyway, good luck, Xi!

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

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" (

Jeremiah Dittmar, "Information Technology and Economic Change: The Impact of the Printing Press" (

James Feyrer and Bruce Sacerdote, "Colonialism and Modern Income: Islands as Natural Experiments" (


Elise Huillery, "History Matters: The Long Term Impact of Colonial Public Investments in French West Africa" (

Melissa Dell "The Persistent Effects of Peru's Mining Mita" (

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

mother breastfeed and children health

This is an interesting topic: the behavior of mother breastfeed and children health. Yes, it is the topic of a seminar I audited yesterday.

As usual, here is the related information:

Why Do Mothers Breastfeed Girls less than Boys? Evidence and Implications for Child Health in India [click here to download PDF]
Seema Jayachandran (Stanford University)
UPF Labor, Public, and Development Seminar

Well, although I'm a kind of being addicted to theoretical works, this kind of empirical is still attractive.  She analyzed the development of children health with respect to mothor's breastfeed behaviors. As she said, it is like "quality instead of quantity", and mothers are paying more and more attention to ensure the health of their children.

Fortunately, one guy who lives nextdoor to me has been worked in the field of public health for the last year, and he has lived in India for several years, thus before the seminar he told me many things about the real situation in India. In this way, far beyond listening to the seminar itself, I have learned more about public health, or health economics which is really hot now.

The forever pain for an econometric or empirical analysis is the accuracy of data. She was using NFHS (National Family Health Survey) and DHS  (Demographic and Health Survey) data. However, my nextdoor told me that there were some problems in the questionnaire used, which will influence the reliability of the data, or the answer from those women. He doubted whether it would have potential influence on the regression analysis.

It was also interesting to hear that so many audience there had different kinds of interesting questions.  That is partically why I love economics seminars. But still the question for me is that I am still not able to follow all of the presentation. Apparently I need to store more knowledge.

By the way, I also listened to another seminar this week, it is

Misspecification in Models for Trends and Cycles
Andrew Harvey (University of Cambridge)
UPF Occasional Econometric Seminar

Well, it was a theoretical work, but it was theoretical economics, and I have no idea with that. Unfortunately, I went there early and sat down in the second row of the classroom. Therefore, I had to pretend that I was focusing on what he talked about, but in fact I could not understand anything except HP filter. Oh my poor econometrics, and my poor time series analysis. It also proves that I need to learn more to completely understand the top seminars. Carry on!

At last, I'd like to copy some conclusions from Semma's paper here.

  • the duration of breastfeeding negatively correlates with the mother's likelihood of a subsequent birth.
  • breastfeeding increases with birth order; if parents have a preference for sons, then boys are breastfed more than girls; children with older brothers are breastfed more; these gender e ects are smallest for high and low values of birth order
  • breastfeeding the current child helps prevent or delay a subsequent pregnancy, and a subsequent (perhaps unwanted) pregnancy often causes mothers to wean the current child.
  • If contraception crowds out breastfeeding, then policy makers might consider pairing contraceptive campaigns with promotion of breastfeeding or improvements in water quality. Conversely, if contraception enables a mother to breastfeed her children longer because she can space them further apart, then policies that expand access to contraception might have an added bene t of encouraging breastfeeding.