经济学人-信息不对称之柠檬市场理论与效应(上)

经济学人:信息不对称之柠檬市场理论与效应

（上）

Economics brief : six big ideas . 经济概要：六大经济思想。

Information asymmetry: Secrets and agents 信息不对称：秘密和代理

George Akerlof's 1970 paper,

“ The Market forLemons ” ,is a foundation stone of informationeconomics, the

first in our series on seminal economic ideas.

六大经济思想之一，乔治·阿克洛夫 1970 年的论文——《柠檬市场》，它是信息经济学的一块基石。

In 2007 the state of Washington introduced a new rule aimed at making the l

abour marketfairer: firms were banned from checking job applicants' credit s cores.

2007 年，华盛顿州引入了一项旨在让劳动力市场更公平的新法律：企业被禁止核查求职者的信用得分。

Campaigners celebrated the new law as a step towards equality — an applica

nt with a low credit score is much more likely to be poor, black or young.

发起这项运动的人欢呼庆祝，认为这是通向平等的一步——信用得分低的求职者极有可能是穷人、黑人或者年轻人。

Since then, ten other states have followed suit. 自那以后，又有十个州如法炮制。

But when Robert Clifford and Daniel Shoag, two economists, recently studied the bans, theyfound that the laws left blacks and the young with fewer jobs, n ot more.

但是，日前，当两位经济学家——罗伯特·克利福德和丹尼尔·绍格——研究了这些禁令时，他们发现，这些法律带给黑人和年轻人的工作更少了，而不是更多。

Before 1970, economists would not have found much in their discipline to he

lp them mull this puzzle .

放在 1970 年之前，经济学家是不会在这门学科中找到太多的东西来帮助他们仔细思考这个迷的。Indeed, they did not think very hard about the role of information at all. 实际上，他们当时根本就没有很努力地去思考信息的作用。

In the labour market, for example, the textbooks mostly assumed that empl

oyers know the productivity of their workers — or potential workers — and, th anks to competition , pay themfor exactly the value of what they produce .

例如，那时的教科书大都假设，在劳动力市场中，雇主知道他们的工人——的生

或者潜在的工人产率，而且，由于竞争，是按照工人所生产的东西的价值给他们开工资的。

You might think that research upending that conclusion would immediately b

e celebrated asan important breakthrough .

人们可能认为，颠覆这一论断的研究立即会被誉为一项重大突破。

Yet when, in the late 1960s, George Akerlof wrote “ The Market for Lemons ”which did just that,and later won its author a Nobel prize, the paper was rejec ted by three leading journals.

然而，当乔治·阿克洛夫于上世纪 60 年代末期写出恰恰实现了这种突破并为作者赢得了诺贝尔奖的《柠檬市场》时，这篇论文曾遭到三家主要期刊拒绝。

At the time, Mr Akerlof was an assistant professor at the University of Californ ia, Berkeley; hehad only completed his PhD, at MIT, in 1966. 那时，阿克洛夫是加州大学伯克利分校的一名助教；仅于 1966 年在麻省理工完成了博士学位。

Perhaps as a result, the American Economic Review thought his paper's insigh ts trivial .也许是因为这个原因，《美国经济评论》认为他的论文的观点微不足道。

The Review of Economic Studies agreed. 《经济研究评论》同意了这个看法。

The Journal of Political Economy had almost the opposite concern: it could not stomach thepaper's implications.

《政治经济学杂志》有着几乎完全相反的担忧：它可能消化不了这篇论文深远意义。

Mr Akerlof, now an emeritus professor at Berkeley and married to Janet Yelle

n, the chairman ofthe Federal Reserve, recalls the editor's complaint:

“ I fthis is correct, economics would bedifferent. ”

如今已是伯克利分校名誉教授并同美联储主席珍妮特·耶伦成婚的阿克洛夫还记着那位编辑的不满：“如果这是正确的，经济学会截然不同。”

In a way, the editors were all right. 从某种程度上来说，这些编辑当时都是对的。

Mr Akerlof's idea, eventually published in the Quarterly Journal of Economics in 1970, was atonce simple and revolutionary .

最终于 1970 年在《经济学季刊》上发表了的阿克洛夫的思想即是简单的，也是革命性的。 Suppose buyers in the used-car market value good cars —“ peaches ”

—at $1,000, and sellers at slightly less.

假设，二手车市场中的买方给好车——“桃子” ——估价 1000 美元，卖方要稍微少一点。

A malfunctioning used car —a “ lemon ”

—is worth only $500 to buyers (and, again, slightly lessto sellers) .

一辆瑕疵二手车——“柠檬”，对买方而言，只值 500 美元 (而且对卖方来说，又要稍微少一

点 )。

If buyers can tell lemons and peaches apart, trade in both will flourish .