Wednesday, March 05, 2008

Day 4: Moving Around

第四天在日本,今天不上課,所以表示我可以到處逛一逛。我的日本朋友 Ryo Kawasaki 跟 Shin Kishimoto 帶我逛東京。買一張710日圓的東京地鐵通一日票,就開始當觀光客了。我很討厭當觀光客,尤其是一直照相,看起來很蠢。但是這一次旅行,我照了很多照片,因為我的忠實讀者想看。所以,我現在就跟各位分享一些照片,及簡單介紹他的內容跟故事。

Senso-ji Temple (浅草寺)
我們第一站到 Asakusa Station,去淺草寺。首先跟各位介紹一下日本的宗教信仰。日本有兩種盛行的宗教: "佛教" 及 "Shinto (神道)"。淺草寺是佛教的,而我星期天去的明治神宮是神道的。當初,唐朝我們中國人將佛教引入日本,引起當時的日本人熱烈的迴響。原因很簡單,日本的神道沒有講關於人死後的事情 (after-life)。然而,佛教裡的 after-life 描繪得相當清楚,所以最後日本將兩個叫互相結合。因此你在路上隨便抓一個日本人問他是什麼教,90%會跟你講神道,而85%會跟你講佛教,所以很多是兩者都信的。然而,還是有許多不同處。例如,一般的佛教的廟會拜神像,但是神道多半會拜大自然,因此明治神宮的周圍的樹木就是人工林。


我和 Shin Kishimoto。


我和 Ryo Kawasaki。


個位有沒有發現,這有五層,每一層代表了日本深受佛教影響的五個元素: 地,風,火,水,空。


我抽了籤,上面寫 "凶"。最差的籤。奇怪的事我當時籤筒怎麼倒都倒不出籤,後來到初 "83" 一看這張紙條寫的,我趕緊去買護身符。希望運是可以改善。期實,把籤綁在那裏應該就可以將壞運給留在那。(最後得知: 淺草寺有60%是最壞的籤)



話說這個煙可以治病,你希望變聰明就讓煙薰一下頭。照理來講,煙是要花錢買的,但是他有嚴重的 free rider 問題,所以我猛薰免費的煙。(記住,我剛剛才抽到一張說我會病一整年的籤)



這裡可以清洗你的靈魂。先用右手將瓢子裡的水洗左手,再用左手洗右手,最後再用水清洗嘴。很多人喝下去了,我沒有,但是現在回想抽到那籤後,應該喝下去的。

在 Asakusa 站外面,可以看到 Asahi 飲料的公司總部:

當時設計是讓那金黃色的東西站立的,但是因為擔心會有安全問題,所以現在看起來像 "金子"。

我們還去了 Akihabara,但是因為星期三 Cosplay 那一些人還沒有出沒,所以沒有特別好玩。我們到是有去一家咖啡館,裡面的服務生都打扮成傭人,裙子很短,女生也蠻可愛的。不好意思,我沒照相。我星期天又去了一次 Akihabara,照了一些 cosplay 的。

Tokyo Tower (東京鐵塔)
很多人說,日本人很會模仿跟抄襲,東京鐵塔是一個很好的例子。他看起來就像巴黎的 Eiffel Tower,那是因為他的靈感就是從那裏來的。而他又比 Eiffel Tower 更高,又更輕。他們真的鰻會模仿的,但是最後弄得比你好。他是橘白相間的是因為飛安的考量。



從東京鐵塔看到的 Rainbow Bridge。他連結到了 Odaibo。若天氣好的話可以從東京鐵塔看到富士山,但是當天雲層太低。
我下一篇在跟各位分享我星期六去新宿玩的一些照片跟感想。

Day 3: Ominous Meeting

我先聲明,我到時候會開始整理上課的東西,但是先寫一些有趣的事。

我星期二晚上,在上野逛街,走到一個小巷裡,小巷似乎很多小館可以吃東西,但是更引起我注意的事一群穿著黑色的大衣及西裝,髮型挺酷的,站在小巷的兩旁,每走四步就有一個。他們也是我第一次發現日本人在街上吐痰。我走一走發現,跟我一起走進巷子裡的人都不見了,所以我也就趕快轉到另一個地方。過不久後,我就發現一群警察往那邊跑。

我回到房間問我的日本朋友,那一些人是誰? 他說極有可能是 Yakuza

才第三天就看到日本世界有名的黑幫。

Tuesday, March 04, 2008

Day 1: Arrival

這我第一次自己出國。

我去過很多地方,但是這一次是我第一次自己出國。幸好我的第一次是在日本! 因為日本所有東西都標示的很清楚,所以做車轉車都沒有問題。但是,若沒有來過,一定會很緊張,因為那鐵路線簡直就像蜘蛛網,密密麻麻的。又怕語言不通,什麼事都做不了,但是還好寫中文他們看得懂,所以一覺得開始雞同鴨講實,馬上拿紙筆出來寫中文,他們就開始: "Ah! sodesgane!" 更重要的是他們都很熱心。
我從成田機場出來時,有兩種車可以到上野: skyliner 或 limited express。兩個都是同一個線上
的,skyliner 要將近 2000 yen,而 limited express 只要1000 yen。但是limited express 大約慢個 20~30分鐘。因此我選擇了便宜的,但是這是對的選擇也是錯的選擇。錯是因為 skyliner 有指定座位,而limited express 沒有。我在terminal 2上車,所以車 上已經坐滿了人,但是沒有關係,因為過了兩站就有兩個人下車。正當我要做下去的時候,有三個婆婆上車,我發現都沒有人讓位,我就站起來讓位給他們 。(我發現,好像都只有我再讓位置給老人,每一天做都只有我。)
這一讓就不妙了,因為之後的站都沒有人下車。上野剛剛好是最後一站,而我就在那邊站了將近一個小時。直到做到接近倒數幾站時,才有人開始下車,我才有位置坐。

那為何坐對車呢? 因為同一個車廂上有一位很漂亮的女生。後來我終於有位置坐時,他就坐我旁邊,而坐我們對面有一個男的一直在打PSP,打得目不轉睛,他後來偷看了那個女的一眼,之後就沒有專心打PSP了,每打五秒就偷看一眼。

日本東西真的很貴! 想吃一頓好東西就要花一點錢,而當你看到便宜的東西時,你就會發現被騙,因為實際的東西比圖片上來的小太多!

Saturday, March 01, 2008

Destination: Japan

Leaving for Japan tomorrow.

Friday, February 29, 2008

Level-k Thinking: New modeling possibilities?

有趣的觀點:

Consider a game where everyone in a classroom picks a number between 0 and 100. The person closest to half the average wins.

Obviously, picking a number over 50 would be silly. Based on this, picking a number over 25 would be silly. Similarly, picking a number over 12.5 would be silly. Continuing this line of thought, picking any number other than 0 would be silly. These thoughts show the level of thinking of those involved, from level-1 to level-infinity.

Level-k thinking analyzes such games. In actual experiments, players never pick 0, which would be suggested by a Nash equilibrium. Instead, they utilize many different levels of thinking.
使用 Level-k 來 model 不外乎就是讓均衡符合實際的狀況。但是他有一個很強的假設,level-2 的 player 一定要假設他認為其他的 player 是 level-1 或更低,他不能認為有其他 player 是 level-3 或以上的。因為若他認為有人是 level-3,則理性的他,就不再是 level-2 了。

所以為了讓結果更符合實際狀況,level-k thinking 使用了同樣不合理的假設。

Good Book: The Logic of Life - Uncovering the New Economics of Everything

我只有讀第一章,但是已經馬上愛上 Tim Harford 的文筆了。

第一章,Harford 就解釋為何經濟學是一個很好的工具。念經濟學的人,念到最後會時常對這科目失去信心,不相信自己念的東西。然而,Harford 這本書是試圖說服大眾經濟思維裡的 "理性" 的強大力量,他同時也讓我重新找回對這科目的興趣。他寫道:



Does this mean that rational choice theory is as much use as flat earth theory? No. It's more like a perfectly spherical earth theory. The earth isn't a perfect sphere, as anyone who has climbed Mount Everest will tell you. But it's nearly a sphere, and for many purposes, the simplification that the earth is spherical will do nicely.

Thursday, February 28, 2008

歐巴馬的經濟智囊團

From

Like Bill Clinton in 1992, Obama's campaign boasts a cadre of credentialed achievers. Intellectually, however, the Obamanauts couldn't be more different. Clinton delighted in surrounding himself with big-think public intellectuals--like economics commentator Robert Reich and political philosopher Bill Galston. You'd be hard-pressed to find a political philosopher in Obama's inner wonk-dom. His is dominated by a group of first-rate economists, beginning with Goolsbee, one of the profession's most respected tax experts. A Harvard economist named Jeff Liebman has been influential in helping Obama think through budget and retirement issues; another, David Cutler, helped shape his views on health care. Goolsbee, in particular, is an almost unprecedented figure in Democratic politics: an academic economist with a top campaign position and the candidate's ear.

Friday, February 22, 2008

可以從台灣身上學的寶貴經驗

今天早上在德州上演了一場對決: Obama vs. Clinton 的辯論

我個人認為Obama四平八穩,有領導者的風範,而Clinton的表現也非常有風度,雖然落後但是仍然很有風度 (不像台灣的政治人物)。但是很顯然的Clinton很想強調自己的健保提案比Obama的更好。而觀察家竟然一致同意,Clinton的確在健保上勝Obama。

But it was by no means a poor performance for Clinton, and she did successfully draw some contrasts with Obama on his health care stance — an issue in which she holds the upper hand. Obama's plan could leave many uninsured, and Clinton effectively stressed this point in one of her strongest moments of the debate. She immediately put Obama on the defensive about his own plan and proved she understands this issue through and through.


????!!!!!!

這太可笑了! Clinton的健保是一個mandante。也就是所有的人都要購買健保,不購買者會被罰錢的! 但是Obama是降低價格好讓大家都有機會享有健保。一個是有選擇餘地的,另一個是被逼迫的,你要哪一種!?

Clinton的政策不只違反經濟sense,也違反了美國建國的精神!

只是一場選舉

Great Piece!

This election is certainly important. But based on the historical record, it isn’t likely to result in a major swing in economic policy. Fundamentally, democracy is not a finely tuned mechanism that can be used to direct economic policy as a lever might lift a pulley. The connection between what voters want, or think they want, and what ultimately happens in the economy, is far less direct.

.....THAT might sound pessimistic, but it’s not. Many Americans will be living longer, finding new sources of learning and recreation, creating more rewarding jobs, striking up new loves and friendships, and, yes, earning more money. Just don’t expect most of these gains to come out of the voting booth or, for that matter, Washington.
這是在講美國的選舉。但是廣義而言這也可以當成今年所有面臨抉擇的選民所必須面對的事實,其實,你今年選誰對你的影響其實是有限的。

Sunday, February 10, 2008

Wisdom of the Crowd

Terrific website!

以後有什麼國際大事應該參考這個! 不知道什麼時候會放台灣大選的預測?

ps. 看樣子,Obama 極有可能被民主黨提名! Which is great!

Saturday, February 09, 2008

Pedal to the Metal: What happens when signals change


上星期有一則新聞:


在紅綠燈上加裝倒數計時器日漸普及,但交通部運輸研究所的報告指出,加裝綠燈倒數器的路口肇事件數比設置前多一倍,加裝紅燈倒數器則減少一半,兩者兼有的路口肇事件數增加一九%。運研所建議,儘速拆除綠燈倒數計時器,或關閉功能。


這個跟 prospect theory 下的 loss aversion 有沒有關係? 我個人覺得有。


我猜想(也希望)若期望理論的基礎能更穩固,他能解釋更多元的人類行為,也能帶給個經一些新的刺激。

Tuesday, February 05, 2008

老虎伍茲 vs. 其他選手: 其他選手會變弱?


答案是:會!

簡單來講,老虎伍茲太強了!所以搞的其他選手都沒有誘因好好打。

What Every Economics Lecture Should be Like

Steven Levitt 寫說他有一次請了一位特別來賓到他的課堂上:

I brought in a very high-priced call girl to guest lecture at my undergraduate
Economics of Crime class.


那堂課的評價呢?:

The next day, I asked my students whether they liked the lecture. More than one-third of them said it was the single best lecture they had attended in their
four years of college. I had to agree with them.


話說那一堂課有一些有趣的對話:

One of his research subjects is a former computer programmer who charges $300 an hour as a high-end call girl. Levitt asked her if she was happy when her “client line” rang on her Palm Pilot. She told him that she wasn’t happy, but indifferent. He told her that meant she was not charging enough for her services. Later,Levitt offered to pay her the hourly rate she charged clients if she would come speak to his economics class. He was surprised, however,when one of the students asked the prostitute what she charged and she replied, “$400 an hour.” The student then asked her how she had determined that rate. “She turned to me,” Levitt recalled, “flashed me this huge smile and said, ‘Well, I was talking with Professor Levitt and he convinced me that my services were worth more than I was previously charging.

Thursday, January 31, 2008

研究生的態度

我今天看到的一句話:

By grad school, students know the drill cold: read assignments, hear lectures, do homework, and spit it all back on the exam. Problem is, just then the game changes from grades to papers; few will care about your grades, compared to your research papers, written and published. A research paper is not a term paper, and can't be dashed off the weekend before it is due. A research paper does not offer a broad overview; it says something specific and new, even if minor, that fits in a context of other research papers.

看到這一句很感動! 因為上一學期的實變把我搞瘋了,不但被當 (人生第一次被當) 也影響到我其他科目的表現,因為花太多時間在那上面導致我很多經濟的課都是臨時抱佛腳。

結論: 用心在研究上是研究生的職責!

Good Economics vs. Bad Economics

我想最近大家可能都忙著想一些新鮮的題目,試圖尋找自己的經濟見解。但是,若你像我,時常胡思亂想,將一堆學過的東西串在一起,最後發現整個邏輯很勉強,甚至到最後連自己都無法說服時,你可能就是一開始就是錯的。所以有沒有什麼方法可以一開始就檢視自己的理論是不是對的呢?

我最近在讀一本書,名叫 "Discover Your Inner Economist - Use Incentives to Fall in Love, Survive Your Next Meeting, and Motivate Your Dentist." 這一本書是 Tyler Cowen 所寫的,所以喜歡閱讀他的部落格的人會覺得他所引用的例子或故事相當熟。他在第一章有提到說要如何辨認 Good Economics 或 Bad Economics 的方法,我認為這方法非常適合大家,例如學生或做研究的人,在此跟大家分享:

1. The Postcard Test: 你的理論的概要必須在一張小卡片上就能闡述清楚了。
2. The Grandma Test: 你的奶奶必須能夠聽懂你的理論。
3. The Aha Test: 你的奶奶聽完你的理論後必須要有一點驚喜感,最後要點點頭說: "有道理!"

若你的理論無法做到這三點,你的理論就可能太複雜,也很可能就是錯的。

Sunday, December 09, 2007

Jp-Tw Contract Theory Conference

我昨天 (12/8) 跑去中研院參加 Contract Theory 的研討會。這個研討會說起來挺有趣的,因為日本自己每一個都定期來一個Contract Theory Workshop。(Relevant Information: here and here。) 但是這一次來台灣跟咱們聚一聚,一起腦力激盪。

昨天學到相當多的東西,大部分在於如何問問題。昨天許多問題與建議我覺得都非常好。我也覺得我應該加強這一點,參加了那麼多研討會,總覺得自己得直覺反應不夠快,但是有再進步,畢竟我也發現許多提出來的問題,也是我心中的疑問。

但是重頭戲在晚上! 我帶著我朋友,邱哲良,一起跟他們吃飯。一到餐館發現,有四張桌仔,而有人問起: "哪一張是主桌?" 我就看到服務小姐,指著窗旁角落的桌子。而我也看到周嗣文,蔡崇聖,周瑞賢,我們清大的老師都坐在那裡,我也有一股衝動想坐在那裡,但是聽說是主桌就自己找了一桌坐。沒有想到,盡然有兩個日本人跑來跟我們坐,所以我就展現我的熱情開始跟做我左邊的日本人聊天。我問他叫什麼名子,他就把他的名牌秀出來給我看,我一看到我就知道我做錯桌子了,上面寫著 Hiroshi Osano,是這一次的 oraganizer 之一,正當我心中開始有一股涼意時,我看到陳恭平老師也跑來,坐在Osano的旁邊,那時是我這冬季以來第一次感到寒冷。但是,沒有關係,因為其他坐在那一桌的台灣同胞,都以為我們是日本人,所以陳恭平老師還用英文到酒給我喝,我也喝了,身子也暖起來了。最後發現我會中文,才知道我只是一個台灣的小毛頭。

整個晚餐氣份很好,那一些日本人很好聊,他們對台灣的吃的很有興趣,而我也對日本的文化有一點興趣,昨天聊了很多有關皇室的事情,因為作在邱哲良旁的Shinsuke Kambe在皇室成立的大學教書。他們也對我的手機感到興趣,他們覺得太小了! 很好玩!

後來我的老師又帶大家去喝酒,我也就跟著去了,最後喝的醉醺醺的,不知東南西北,只好跟著邱哲良到他的家去過夜。以後不能喝太多酒!

Monday, October 15, 2007

Nobel Prize in Economics 2007

Goes to Leo Hurwicz, Eric Maskin, and Roger Myerson, "for having laid the foundations of mechanism design theory."

這是我 之前 (現在??) 很有興趣的領域,機制設計。這領域數學能力要有一定的基礎,頭腦要非常清楚。

我今年初有去聽 Eric Maskin 在台大舉辦兩天的講習,教導大家基本的機制設計的觀念。他給我應向非常深刻,他用淺顯易懂的例子就將我在論文上看不懂的東西給解釋清楚了! 超強!

所以說,我也是有被諾貝爾獎得主教過的人。

More on this later this week.

Thursday, October 11, 2007

Economics Nobel Predictor 2007: Part 2

The odds at Ladbrokes.

Helpman and Grossman 仍然是 favorites! 但是 Bhagwati 的名子竟然沒有在上面。

悲亢的詩 (北島)

〈回答〉──北島

卑鄙是卑鄙者的通行證,
高尚是高尚者的墓誌銘。
看吧,在那鍍金的天空中,
飄滿了死者彎曲的倒影。
冰川紀過去了,
為什麼到處都是冰淩?
好望角發現了,
為什麼死海裏千帆相競?
我來到這個世界上,
只帶著紙、繩索和身影,
為了在審判之前,宣讀那些被判決的聲音:
告訴你吧,世界
我-不-相-信!
縱使你腳下有一千名挑戰者,
那就把我算作第一千零一名。
我不相信天是藍的;
我不相信雷的回聲;
我不相信夢是假的;
我不相信死無報應。
如果海洋註定要決堤,
就讓所有的苦水都注入我心中;
如果陸地註定要上升,
就讓人類重新選擇生存的峰頂。
新的轉機和閃閃星斗,
正在綴滿沒有遮攔的天空,
那是五千年的象形文字,
那是未來人們凝視的眼睛。

Sunday, September 30, 2007

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?

Tuesday, September 25, 2007

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。

Monday, September 24, 2007

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。

Sunday, September 23, 2007

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?

Saturday, September 22, 2007

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!

Thursday, September 20, 2007

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!!

Saturday, September 08, 2007

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!

Thursday, September 06, 2007

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!


Wednesday, September 05, 2007

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!

Sunday, September 02, 2007

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

Monday, August 27, 2007

The Existence of Hierarchies

目前大部分的經濟理論都無法完善的解釋公司內部的結構,尤其是謂何會有階層的現象 (老闆,經哩,員工)。有一些公司大到階層超過幾十個!! (我之前有blog過hierarchies)

目前再實證上也無法確切的橫樑一家公司的 "身高"。因此再這方面的時正研究很少,而有做此研究的經濟學家都是使用顧問公司所提共的資料。這有許多問題。第一,資料很貴。第二,資料所有權是顧問公司的所以無法像其他學者分享。第三,公司有幾個階層的定義很難決定,任何資料都將有爭議。



實證的問題我們先不提,就連理論的問題都很難解決。而目前較popular的模型是中國的經濟學家,錢穎一所提出的。(Link to paper: INCENTIVES AND LOSS OF CONTROL IN AN OPTIMAL HIERARCHY) 今天先就簡單介紹一下吧!

錢穎一的主軸是 moral hazard (道德風險) 跟喪失控制能力 (loss of control)。先講moral hazard的部份。假設今天有一位老闆,雇用了20位員工,但是老闆沒有辦法隨時隨地都看著他們工作,因此員工就有偷懶的頃向。假設老闆只能抽一位員工來檢視,因此每一位員工有1/20的機會被老板檢查,員工偷懶的情況稍微改善了,但是能更好嗎? 今天老闆能在僱用4個經理人,而每一個經理管5個人,所以每一個員工有1/5的機會被經理檢查,因此員工的偷懶狀況大大的改善了,員工出力也變多。那老板呢? 只要監視這4位經理就好了ㄚ! 因此每一位經理有1/4的機會被老闆盯。而一個職員管理的人數就稱做為 span of control (控制範圍)。

那麼若加一個層級這麼好,我們家無數多個就好啦! 但是經濟學上有一個現象較loss of control。這最早是Williamson所提出的。他的意思是越多層級的公司,最下面一層的員工,每一位所能生產的量會下降。這個現象的力量是從哪來也不清楚,但是想一想還蠻合理的。因此家越多層級,最下面一層的maximum生產量就會下降。因此老闆的問題就是在span of control跟 loss of control之間做最適化。

以下是一個較technical的簡介:






Sunday, August 26, 2007

Wednesday, August 22, 2007

Q&A: 台灣英文菜嗎?

今天新聞都在報導最新出爐的 TOEFL 及 IETLTS 的考試成績排名。在那個排名當中,台灣是倒數的。使的大家開始懷疑我們外語教育即能力。台灣是非常注重英文能力的國家,為何成績會這麼差? 但是我要提出的疑問是,光從這個排名就可以斷定我們的英文能力嗎?


我認為台灣考TOEFL或其他語文測驗的目的跟其他國家不一樣。考TOEFL不外乎就是要出國留學,這也是大部分的國家考TOEFL的原因,但是台灣許多的工作也會希望看你的TOEFL成績。會不會因為考試的目的不同,所以造成準備的心態不一樣,導致考試出來的成績不一樣? 例如,我相信在日本考TOEFL的人都是要出國的人,而要出國的人通常對自己的英文程度是有信心的,也通常做了很透徹的準備。


另一個疑點就是,這個排名是看平均成績,但是標準差呢? 我相信台灣的標準差會比其他國家大很多,因為考試的目的種類較多。我也相信若拿台灣考試成績的前百分之十跟其他國家比,成績會很亮眼。

Forensic Economics


美國有一個很紅的電視劇叫CSI,每一集的故事就是有一群forensic scientists,利用科學的方法分析證據尋找壞人。近幾年來forensic science在美國越來越紅,主要原因就是因為這齣劇跟李昌鈺的關係吧。


然而,現在執法者也越來越養賴經濟學家了,而經濟學家也對crime也越來越有興趣。其實經濟學家很早就開始研究犯罪了,但是因為蘋果橘子經濟學(freakonomics)的興起,使得大中開始了解經濟思維在這方面也有貢獻之處,因此執法單位開始聽取經濟學家的建議了。


例如,最近有一篇文章 "利用證據" 試圖找尋 "非法武器交易" (就像軍火之王)。他們所使用的證據是 "股價"。當UN的武器交易法變嚴格時,他們發現比較有可能從事非法交易的武器公司的股價會相對上升, 而遵守法律的公司會相對下降。

Friday, August 17, 2007

Friday, August 10, 2007

I have a Question

一般來講,大部分的人都認為網路的便利性帶來更快更準確的資訊。但是我在想一個問題,資訊科技的進步不是也更容易讓一些人魚目混珠嗎? 譬如說,有一家牙一診所很差,網上一定會有人給他不好的評價,但是相對而言謊的成本也變小了阿! 也可以有人說這診所的牙醫很好,而我們閱讀的人也不知道誰講的事實話。

也就是,之前在資訊科技還未成熟時,要傳達訊息的成本比較高,因此有separating equilibrium的出現,不好的牙醫要打廣告太難了。但是現在,傳達訊息的成本極低,普遍而言(對我來說)都是pooling equilibrium,因此不好的牙醫要做廣告挺容易的,人們無法分出好牙醫跟不好的牙醫了。因此一般的假設是不是錯了?

The Power of Television

Jensen and Oster's new research:

Cable and satellite television have grown rapidly throughout the developing world. The availability of cable and satellite television exposes viewers to new information about the outside world, which may affect individual attitudes and behaviors. This paper explores the effect of the introduction of cable television on gender attitudes in rural India. Using a three-year individual-level panel dataset, we find that the introduction of cable television is associated with improvements in women's status. We find significant increases in reported autonomy, decreases in the reported acceptability of beating and decreases in reported son preference. We also find increases in female school enrollment and decreases in fertility (primarily via increased birth spacing). The effects are large, equivalent in some cases to about five years of education in the cross section, and move gender attitudes of individuals in rural areas much closer to those in urban areas. We argue that the results are not driven by pre-existing differential trends. These results have important policy implications, as India and other countries attempt to decrease bias against women.

Sunday, August 05, 2007

唱歌像ABC

前幾天我陪我媽看超級星光大道。我發現許多參賽者都唱歌唱的像ABC一樣,於是我開始想為何要這樣?

很直覺的答案是因為他們在模仿一些歌手。我雖然不了解台灣的音樂家,但是有幾個有名的好像都是從國外回來的,因此唱歌很自然的會有ABC的感覺。但是我覺得這不是原因,因為這樣唱並沒有加分效果,尤其是若一大堆人都這樣唱。

我今天後來在車上聽到費玉清唱的 "秋蟬" 我才想到答案。因為這些歌手國語發音不標準! 若唱腔帶有ABC的味道的話,就可以掩飾咬字不清的毛病,我開始懷疑周杰倫唱個像念經一樣也是這個原因。

ps. 我很看好林柏宏這位參賽者!

台灣的大學會太多嗎?

前一陣子,在報紙上看到台灣從明年開始會少掉10個大學。台灣目前有幾個大學我不清楚,似乎有上百個,這樣會太多嗎?


我發現減少大學數目的 argument有兩個是比較常拿出來的:
1. 大學聯考錄取率太高。
2. 跟其他國家比,台灣的大學數目太多。



我不知道台灣的大學是不是太多,但是上面兩個理由不足以說服我。

1. 我爸說錄取率在他們那個年代不到百分之30%,大學也就只有那幾個可以填。但是現在95%的人可以唸大學有什麼不好? 不是越多人受過教育越好嗎? 盡管他以後拿到學位但是工作可能是搬運工,他所獲得的教育在許多其他方面是可以幫他做判斷的。我不認為社會上有高學歷的勞工是不好的現象,我甚至認為是有助於提昇社會的品質。



2. 為何每一次探討這類議題台灣都有跟別的國家比較? 台灣的教育市場跟就業市場非常像別的國家的嗎? 別的國家的政策研究結果就適合我們嗎? 這就是屬於統計上external validity的問題。台灣的教育需求可能比其他國家大很多,因此才有這麼多大學阿。而且若大學太多,這些學校會自己想辦法招生。像為何沒有學校想過招大陸的學生來年? 若我們政府同意的話,台灣的大學可能還不夠呢!

Saturday, July 28, 2007

Genius Economist

Marginal Revolution 今天介紹了一位天才經濟學家。年紀比我輕但是明年就要拿到Phd,而且已經有一篇很多人引述的論文。

他的名子叫Glen Weyl,研究方向跟我的興趣很相近。

Tuesday, July 24, 2007

Econ Concepts 12: 統計檢定的必要性

最近有一位NBA裁判涉嫌簽賭,造成體壇的轟動。而前一陣子,Wolfers 跟 Price 兩位經濟學家又發現NBA裁判有種族歧視之嫌疑The Sports Economist post了一篇非常好的文章,可以提共給大家,同時這個post也強調了統計的重要性:




Astute economists here and elsewhere noted that the level of bias observed in the paper amounted to a maximum of .1 or .2 fouls per game per player, a number unlikely to be uncovered by even careful watching of games and video tapes. (Similarly, as noted in Moneyball, the difference between a .300 hitter and a .275 hitter is 1 base hit every two weeks. Hence, Billy Beane relies on his statisticians rather than his scouts.) Of course, the whole reason the field of inferential statistics has been developed is to help discover relationships that cannot be identified through casual (or even intense) direct observation. While there may be valid arguments why Price and Wolfers are wrong, the NBA's claim that "We can't see it with our naked eyes" was always ignorant in the extreme.

Now it comes out that one of the NBA's men in black was apparently on the take, a fact that went unnoticed by the NBA's trained observers until they got a call from the FBI. If the naked eye can't even pick up a guy trying to throw games for the mob, how can there be any hope, aside from well-designed statistical experiements like that of Price and Wolfers, of discovering subtle (and almost certainly, subconcious) racial bias in the NBA?

Monday, July 23, 2007

Emily Oster on AIDS in Africa

你認為你對非洲的愛滋病情況很瞭解嗎? 最近很紅的經濟學家Emily Oster要挑戰我們對愛滋所知道的幾件事

沒時間看video的人,簡單而言:

1. 目前花很多錢在教育非洲人關於性病,這所能達到的效果有限。因為非洲人效用的現值(present value) 很低,沒有得愛滋的平均壽命太低了,所以得愛滋的機會成本不高。因此花這麼多錢在教育上,是無法達到我們的預期效果。

2. UN預測有 25 million愛滋病患,這數字太大了,Oster估計只有 5 million。

3. 貧窮造成愛滋病,因此讓他們開放貿易可以減少愛滋。這觀念有問題,至少在短期而言。在短期內,因為交易頻繁,性病的傳染途徑也增多,因此病例會增加。長期而言,(我認為啦!),使他們變的富有一定能減少病例。

136th Open Championship

每一次在Carnoustie打英國公開賽,我都需要吃鎮定劑,因為這個球場帶給大家的drama不輸任何一本血脈噴張的小說。上一次在這邊打,我跟我家人在Denver度假,那個週末,小甘迺迪與他的妻子乘坐的小飛機墜機,所以第三天的賽事幾乎一直被 breaking news 打斷,那一天,一未不知名的法國佬領先群雄,打完三天贏大家6杆。他的名字叫Jean van de Velde,現在是家喻戶曉的高爾夫球選手,but for the wrong reasons。 再最後一天的最後一洞,他的六杆優勢已減為三杆,但是沒關係,最後一洞只要打double bogey 就可以贏,這連我都做得到! 但是一連串的錯誤選擇使他吞下triple bogey!! 最後在延長賽敗給另一未不知名的選手Paul Lawrie。至今Jean van de Velde再高爾夫球界已經變成一個常用的名詞,意思為 "笨的選擇"。例如,I pulled a Jean van de Velde on the 15th hole。就是我再第十五洞,做了一連串的idiotic moves。聽我講那麼多還不如欣賞以下的片段:

1. Van de Velde 自己解說
2. 老日幫他解釋


(Jean van de Velde 再最後一洞泡腳沉思,還好前一天有刮腿毛。令人痛心的loss。)


而今年的比賽不輸1999年的。先講Andres Romero,一位阿根廷新人,經驗不夠但是球技非常純熟。他最後一天打了十支birdie,只用了24推杆,但是也打了兩個double bogey,其中最傷的就是第17洞。那時他已經領先兩杆,第二杆從長草打出來時卻撞到想西的圍牆,彈到界外。Romero再最後一洞的par putt撞到洞口彈出來,若進的話,還可以打延長賽。但是他還年輕,未來我們還會在見到他。(另一未讓我刮目相看的是Rory McIlroy,這小子會紅。)



(推杆太強了,沒人能抵擋Romero的攻勢,除了最後兩洞。)


再來就是Harrington。Harrington長久以來就是我很喜歡的選手,Mr. Nice Guy。他在第14洞抓下老鷹,躍居領先榜上,到了最後一洞他領先Sergio Garcia一杆,但是他在那一洞卻下水兩次!! 讓大家想起 Jean van de Velde 的戲碼是不是又重新上演。他最後那一洞吞下double bogey,反而落後Sergio Garcia 一杆。但是故事還沒結束。


(Harringtony在想: 我應不應該跳進水裡泡腳學van de Velde? 還是不要好了,我昨天沒刮腿毛。)


Sergio Garcia 站在最後一洞的球道上,手拿著三號鐵,心想只要放在國嶺上兩推就好,但是他卻打到砂坑裡。但是沒關係,還是可以就par。十呎的par推杆離開杆頭時,就一直往洞前進,但是最後卻從洞的左邊lip out! Sergio Garcia,從他18歲時就被譽為會拿下許多大賽冠軍的選手,還需要再打四洞的playoff才能贏。這位西班牙選手,剛出來時,有一點自大,帶著小孩子氣,揚言要跟老虎伍茲PK,但是事隔8年,他仍然沒贏過大賽,也還沒長大,那小孩子氣已經不可愛了,反而惹人厭。他是我最討厭的選手!

Evidence that Sergio is spoiled(大baby要哭了嗎? 都是老天爺的錯! 他又輸了。)

最後,Harrington在延長賽脫穎而出,贏的他的第一做大賽! There is a God!


(Deserving Open Champion,Padraig Harrington!)

(Yeah Baby!)

Saturday, July 14, 2007

我前幾天到哪去了?

我前幾天去參加這個東西: FEMES

我不久後會將一些趣事跟心得跟大家分享,但是請給我一點時間。

Sunday, July 08, 2007

Tiger Teasing Roger

Tiger shows some class in this Nike ad

Wednesday, July 04, 2007

An Economic Question: Buying Furniture

我昨天去買書櫃。我到家具店的現場看家具。我看上一個有門的,四層的。標價5500,但是我連殺價都沒殺,老闆就馬上說賣我750。我目瞪口呆,原本要殺價的心情完全被他毀了。

'請問為何要賣我那麼便宜?' 是一個很直覺的反應。但是應該問 '為何標價那麼高?'。所以我問大家,為何標價那麼高?

Tuesday, July 03, 2007

Econ Concepts 11: Incomplete Contracts

這是我寫的期末報告的Intro的一部份:

Incomplete contract has slowly become one of the hottest topics in microeconomics. It differs from previous approaches because it looks at a restricted set of contracts, usually much simpler. While previous approaches focus on optimizing over a general set of contracts subject to incentive and participation constraints (such an approach is conveniently called complete contracts), the incomplete approach restricts its search of contracts over an admittedly smaller set of contracts. In the end, the simpler contracts often can only specify property rights and control rights. An example will help distinguish these two approaches, and the different issues it focuses on.

One of the simplest and most researched topics in asymmetric information is CEO compensation. The complete contracts approach calls on us to focus on finding an optimal compensation package, such that under this package, the CEO’s incentives are aligned with the stockholders. As a result, it is in the best interest of the CEO to work ‘hard’ for the stockholders. The incentive package that we find using this method is often complex and seldom seen in the real world. There are also other practical implications that do not seem to abide to the observations in the real world. One of the most obvious is that under complete contracts, the two parties, the CEO and the stockholders, never have to renegotiate the terms of the incentive package. Since after offering the incentive package, the stockholders do not have to worry that the CEO will do something that is ‘not’ in their best interest.

Under the incomplete contracts approach, other factors become important, and these factors are often institution related. Continuing with our CEO compensation example, it is obvious that the stockholder’s decision making procedure or the amount of control the stockholders have over the CEO’s decision are also very important.


As a result, the incomplete contracts approach shifts its focus from compensation and incentive inducing issues to institutional and procedural issues. The change in methodology has spawned a rich body of research in industrial organization, corporate finance, and other areas of economics. It has helped make theories more realistic.

However, questions still remain, if a complete contract can be written, then why would anyone write an incomplete one? Several answers have been provided, but all can be classified into three distinct reasons:

1.
Writing contracts is costly. If under the supervision of a lawyer, a payment must be made to the lawyer for each word the lawyer writes, then both parties may neglect to hire a lawyer, or hire one but write up a simpler contract than one without cost.

2. Sometimes states of the world are too complicated to describe and are unable to be included in the contract simply because we can not foresee future
events.

3. Many aspects of the relationship are observable to both parties but are unverifiable to an impartial third party, such as the court. Under these circumstances, the contract is naturally incomplete, since even if such aspects are included, it wouldn’t help when a dispute arises, because an impartial third party will not be able to determine the truthfulness of their claims. Note that this is different from the traditional moral hazard problem. Previous moral hazard problem treated CEO effort as an unobservable variable, but if it was observed, the stockholders can include effort level in the contract. Incomplete contracts treat this problem differently, even if effort is observed, it can’t be included in the contract because it couldn’t be verified by an impartial third party.

Monday, July 02, 2007

大學升碩士的閱讀物

通常大學畢業後,大部分的人都沒心情唸書。但是若你像我,以下幾本是可以幫忙準備經研所的工具。(至少這是我的計畫啦!) 能看多少就看多少,拿消化多少就消化多少。

Math:
1. 數學不用就馬上忘記,複習的最佳夥伴: Alpha Chiang - Fundamental Methods of Mathematical Economics

2. 實變: Efe Ok - Real Analysis with Economic Applications

Microeconomics:
1. 複習 Microeconomic Theory: Philip Reny and Geoffrey Jehle - Advanced Microeconomic Theory

2. 產業組織: Jean Tirole - The Theory of Industrial Organization

3. 賽局: Martin Osborne and Ariel Rubenstien - A Course in Game Theory

Macroeconomics:
1. 複習大學 Macro : Robert Barro - Macroeconomics

2. Economic Growth : Robert Barro and Xavier Sala I Martin - Economic Growth

Econometrics:
1. 複習數統兼融合觀念: Takeshi Amemiya - Introduction to Statistics and Econometrics