The Conflict between an Economist and an Economic Man

我長期以來都覺得經濟學裡的模型將人假設的太"聰明"。但是，經濟學家又認為當這一些人表現的不"聰明"的話就表示他不"理性"。所以理性到底是什麼? 而經濟學家又真得很理性嗎? 下面的故事是 Harry Markowitz (1990年諾貝爾獎得主，CAPM的始祖) 在做投資時的趣事:

"There is a story in the book about Harry Markowitz,” Mr. Zweig said the other day. He was referring to Harry M. Markowitz, the renowned economist who shared a Nobel for helping found modern portfolio theory — and proving the importance of diversification. It’s a story that says everything about how most of us act when it comes to investing. Mr. Markowitz was then working at the RAND Corporation and trying to figure out how to allocate his retirement account. He knew what he should do: “I should have computed the historical co-variances of the asset classes and drawn an efficient frontier.” (That’s efficient-market talk for draining as much risk as possible out of his portfolio.)

But, he said, “I visualized my grief if the stock market went way up and I wasn’t in it — or if it went way down and I was completely in it. So I split my contributions 50/50 between stocks and bonds.” As Mr. Zweig notes dryly, Mr. Markowitz had proved “incapable of applying” his breakthrough theory to his own money. Economists in his day believed powerfully in the concept of “economic man”— the theory that people always acted in their own best self-interest. Yet Mr. Markowitz, famous economist though he was, was clearly not an example of economic man.

所以若這麼天才的經濟學家都無法依照他自己所創的模型做投資決定，我們憑什麼認為現在的經濟學沒有什麼 "重大" 的問題。我個人認為經濟學有很嚴重的問題，需要更新的方法解決。實驗 anyone?

Economics Nobel Predictor 2007: Part 1

九月快結束了! 而十月中，就要公布諾貝爾經濟學獎的得主。有哪一些人有機會得呢?

Thomson Scientific 預測今年這幾位經濟學家有機會:

Elhanan Helpman Galen L. Stone Professor of International Trade Harvard University Cambridge, Mass., USA Emeritus Professor Department of
Economics Tel Aviv University, Israel
-and-
Gene M. Grossman Jacob Viner Professor of International Economics Princeton University Princeton, N.J., USA Professor, Department of Economics Woodrow Wilson School of Public and International Affairs Princeton, N.J., USA
For their contributions to international trade and economic growth.

Robert B. Wilson Adams Distinguished Professor of Management Emeritus Stanford Graduate School of Business Stanford University Stanford, Calif., USA
-and-
Paul R. Milgrom Shirley and Leonard Ely Professor of Humanities, Department of Economics Stanford University Stanford, Calif., USA
For their work, both theoretical and practical, on the mechanism of auctions.

Jean Tirole Scientific Director, Institute of Industrial Economics University of Social Sciences Toulouse, France Affiliated research member of CERAS Paris, France For his research in industrial organization and regulation.

我認為這幾位經濟學家都應得獎，但是應該不是今年得。例如，Jean Tirole 在 industrial organization 跟 contract theory 上有卓越的貢獻，但是論得獎還早了一點。而 Milgrom 與 Wilson 若要拿獎，很難不包含 Krebs 跟 Roberts，號稱 "The gang of four." Helpman 也一樣，講到 international trade，很難想像 Bhagwati 還沒有拿到，所以 Helpman 可能還太早 (不然就是一起得)。

從今天起我每幾天，都會介紹一位我認為有機會得獎的經濟學家。

排隊理論: Part 1 of 2

為何大家要排隊?

排隊是一件非常沒有效率的事情，就拿飲水機來說: 排隊是按照每一個人到來的順序，而不是每一個人的口渴程度排序。因此當一位散步到飲水機喝水的人排在剛跑完4000m的人的前面時，這種結果就很沒有效率。於是就有經濟學家想一個解決這件事的方式，而這個答案非常直接也很簡單，賣位置。

那一位散步而來的人可以將他的位置賣給剛剛跑完的人。其實，這種行為很常見，我們都稱這些人 "黃牛" (我之前有賣過黃牛票，不好賺!)。但是為何不是所有的排隊都可以用此方式解決呢? 有幾個可能的原因:

1. 買票跟排隊喝水只差在，買票可以依次買很多票，而喝水只能一次一個人喝。所以那一位散步的人只能賣給一個口渴的跑者，而那一位賣黃牛的人可以賣給許多個買家。但是占一次位置的fixed cost 很高，只賣給一個人是無法cover的。

2. 若將位置賣給口渴的人，其他位置的人可能會提出更低的價格，最後結果就像 Bertrand competition 一樣。其實我強烈質疑販賣黃牛票的非法性，因為按照一般的分析結果會發現，若販賣黃牛票合法化，會有許多賣家加入，將利潤降到0，因此買黃牛票的人只是沒有時間排隊而已，也不會因此而負更多錢，而原賣家(例如主辦單位)也不會怕黃牛將票價提高。所以禁止販賣黃牛票似乎是道德問題，而非經濟問題。

現在目前的方式雖然很沒有效率但是，大家所提出的解決辦法也都難以實行。我最近閱讀到一個非常特別的解決方式，下一次跟各位分享。

有人看我的部落閣

一位大陸網友 (我不認識)，有看過我的部落閣。

我怎麼知道? 在他的部落格裡，最右邊有一欄為 "形形色色"。請問第一個 link 是什麼?

左右腦

請問上面這個女的旋轉方向為何? (要點一下圖片)

若你看到的為順時鐘，則你的右腦比左腦發達。

若你看到的為逆時鐘，則你的左腦比右腦發達。

若你依開始看到的是逆時鐘，而後突然變為順時鐘，則你的IQ有可能超過160!!

很有趣吧!

The Essential Math

這些是想當經濟學家的必修數學課程 suggested by Greg Mankiw:

Calculus
Linear Algebra
Multivariable Calculus
Real Analysis
Probability Theory
Mathematical Statistics
Game Theory
Differential Equations

我只差 probability theory, and differential equations. 現在正在修real analysis. 這也是為何我最近都沒有寫文章. 因為每星期都有作業!!

More Sex $969

我前幾天去書店買書，書名叫 More Sex Is Safer Sex: The Unconventional Wisdom of Economics. 標題非常聳動!

結帳時，條碼一刷，螢幕卻顯示: MORE SEX $969。That is pretty cheap!

Profile of Robert Barro

The Profile. Still reading it, but this sentence struck me:

It would have been difficult to predict this outcome [of his success in economics] from the title of Barro's first publication in 1970: "The Crystal Structure of a Dimeric Cobalt Compound Containing a Chloro Bridge."

為何Barro沒有繼續研究物理呢?

"Feynman was a great inspiration, but what he taught was often way above my head. It made me realize I wouldn't be close to the top in those fields."

我國中時也非常迷物理，也是被Feynman的書吸引住了。當時我看了他的自傳 Surely You're Joking Mr. Feynman, 至近對我的影響仍然很大，因為是那ㄧ本書讓我對學者的印像改觀。後來在師大附中唸高中時，才發現物理=霧裡。我雖然成績在班上不錯，但是我知道若我繼續追隨當物理學家的夢，我對人類知識的貢獻是非常有限的。我的目標一直是想要有一點貢獻。

A Great Loss: Luciano Pavarotti passes away at the age of 71

The News.

這位歌劇巨星因為胰臟癌去逝。我的阿姨十年前也因為胰臟癌去逝。有醫生說過，胰臟癌末期的病患很難活超過八個月。

我記得我第一次聽到Pavarotti唱歌是我幼稚園的時候。我當時還住在紐約，而紐約的公共電視非常喜歡播放 "三大男高音" 的表演。我記得我被他們的聲音深深的感動，甚至在洗澡間，邊洗邊模仿。

這非常有趣:

.....what appears to have been a normal childhood with a typical interest in sports — in Pavarotti's case soccer above all — he graduated from the Schola Magistrale and faced the dilemma of a career choice. He was interested in pursuing a career as a professional soccer player, but his mother convinced him to train as a teacher. He subsequently taught in an elementary school for two years but finally allowed his interest in music to win out.

During his years of study Pavarotti held part-time jobs in order to help sustain himself — first as an elementary school teacher and then, when he failed at that, as an insurance salesman.

我們應該很慶幸，他選擇了音樂這條路!

Fun Facts About CEO and Firm Value

From recent studies:

[Firm's Value] slid by about one-fifth, on average, in the two years after the death of a CEO's child, and by about 15% after the death of a spouse. As for an executive's mother-in-law, the old jokes seem to hold: The researchers found that profitability, on average, rose slightly after her demise.

非常有趣!

Prediction Tools

非常好玩! 我發現平均而言我可以活到82歲。

還有其餘的一些網站都在這網頁。