经济学怎么了

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[2009.07.18]What went wrong with economics [/B]经济学怎么了[/B][/B]­

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And how the discipline should change to avoid the mistakes of the past ­

这个学科该如何改进以避免过去的错误­

What went wrong with economics经济学怎么了Jul 18th 2009­

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OF ALL the economic bubbles that have been pricked, few have burst more spectacularly than the reputation of economics itself. A few years ago, the dismal science was being acclaimed as a way of explaining ever more forms of human behaviour, from drug-dealing to sumo-wrestling. Wall Street ransacked the best universities for game theorists and options modellers. And on the public stage, economists were seen as far more trustworthy than politicians. John McCain joked that Alan Greenspan, then chairman of the Federal Reserve, was so indispensable that if he died, the president should “prop him up and put a pair of dark glasses on him.” ­

在所有已破灭的经济泡沫中，其所对应经济学的名声败坏往往更引人注目。若干年前，乏味的科学被称为是用来解释更多人类行为模式——从毒品交易到相扑运动——的一种方法。华尔街在最好的大学中寻找经济游戏的理论家和经济抉择的塑造者。而公众认为经济学家比政治家有更多价值。约翰·麦凯恩(John McCain)曾拿那时候的美联储主席艾伦·格林斯潘（Alan Greenspan）开玩笑说，他是必不可少的，如果他去世，总统都应该“戴上黑墨镜来为他抬棺材”。­

In the wake of the biggest economic calamity in 80 years that reputation has taken a beating. In the public mind an arrogant profession has been humbled. Though economists are still at the centre of the policy debate—think of Ben Bernanke or Larry Summers in America or Mervyn King in Britain—their pronouncements are viewed with more scepticism than before. The profession itself is suffering from guilt and rancour. In a recent lecture, Paul Krugman, winner of the Nobel prize in economics in 2008, argued that much of the past 30 years of macroeconomics was “spectacularly useless at best, and positively harmful at worst.” Barry Eichengreen, a prominent American economic historian, says the crisis has “cast into doubt much of what we thought we knew about economics.” ­

80年代，随着最大的经济灾难的出现，经济学的声望就已经受到了抨击。在公众的思维中，这个自傲的职业变得低劣。虽然经济学家仍然在政策讨论起关键作用——想想美国的本·伯南克（Ben Bernanke）和拉里·萨默斯（Larry Summers）或者英国的默文·金 （Mervyn King）——但相比以前，他们的言论要遭到更多质疑。这个行业自身遭受着罪恶和仇恨的影响。在近期的一次演讲中，2008年诺贝尔经济学奖得主保罗·克鲁格曼（Paul Krugman）就说，宏观经济学在过去30年的大多数时间里“最好情况下是极度无用，最好情况下就是危害深重了。”杰出的美国经济历史学家巴里·埃肯格林（Barry Eichengreen）说，这场危机使我们对经济学的认识遭受质疑。“­

In its crudest form—the idea that economics as a whole is discredited—the current backlash has gone far too far. If ignorance allowed investors and politicians to exaggerate the virtues of economics, it now blinds them to its benefits. Economics is less a slavish creed than a prism through which to understand the world. It is a broad canon, stretching from theories to explain how prices are determined to how economies grow. Much of that body of knowledge has no link to the financial crisis and remains as useful as ever.  ­

最粗俗的观点是，经济学总的来说是不值得信任的，而现在，对这种观点的对抗性反应已经在渐渐消失。如果是无知使得投资者和政治家夸大了经济学的优点，现在，无知让他们看不到经济学所带来的好处。与其说经济学是应该盲从的教条，还不如说它是我们用来理解世界的棱镜。经济学是一个大概的准则，它来源于理论，用来解释经济的发展情况是如何决定价格的。经济学的大多数主体知识和金融危机没有关联，并依旧有用处。­

And if economics as a broad discipline deserves a robust defence, so does the free-market paradigm. Too many people, especially in Europe, equate mistakes made by economists with a failure of economic liberalism. Their logic seems to be that if economists got things wrong, then politicians will do better. That is a false—and dangerous—conclusion.  ­

如果经济学作为一门广博的学科值得我们坚定的维护，自由市场体也一样值得。很多人，特别在欧洲，把经济学家犯的错误等同于自由经济主义的一次失败。似乎，他们的逻辑是，如果经济学家做错了事，政治家就能做得更好。这是一个错误的，危险的结论。­

Rational fools ­

大愚若智­

These important caveats, however, should not obscure the fact that two central parts of the discipline—macroeconomics and financial economics—are now, rightly, being severely re-examined . There are three main critiques: that macro and financial economists helped cause the crisis, that they failed to spot it, and that they have no idea how to fix it. ­

但是，以上重要的警告并能掩盖这样一个事实，即这一学科中的两个中心部分——宏观经济学和金融经济学目前确实遭到严格的再审查。对宏观经济学和金融经济学有以下三种指责：他们助成了经济危机；他们没能发现经济危机；他们对经济危机不知所措。­

The first charge is half right. Macroeconomists, especially within central banks, were too fixated on taming inflation and too cavalier about asset bubbles. Financial economists, meanwhile, formalised theories of the efficiency of markets, fuelling the notion that markets would regulate themselves and financial innovation was always beneficial. Wall Street’s most esoteric instruments were built on these ideas.  第一种指责说对了一半。宏观经济学，特别是在中央银行，过度依恋于控制通货膨胀而忽视了资产泡沫。于此同时，金融经济学家把市场效率的理论成为书面形式，激发了市场会自我规范，金融改革总是能收益的观念。华尔街大多数令人费解的证券就是在这种观念上发行的。­

But economists were hardly naive believers in market efficiency. Financial academics have spent much of the past 30 years poking holes in the “efficient market hypothesis”. A recent ranking of academic economists was topped by Joseph Stiglitz and Andrei Shleifer, two prominent hole-pokers. A newly prominent field, behavioural economics, concentrates on the consequences of irrational actions.  ­

但经济学家并不是市场效率的天真信徒。金融学者把过去30年里的大部分时间用来驳斥“效率市场假设”。最近的理论性经济学家排名中，两位杰出的驳斥者，约瑟夫·斯蒂格利茨（Joseph Stiglitz）和安德烈·施莱弗（Andrei Shleifer）排名榜首。行为经济学作为一个新的杰出领域，专注于不合理经济行为的后果。­

So there were caveats aplenty. But as insights from academia arrived in the rough and tumble of Wall Street, such delicacies were put aside. And absurd assumptions were added. No economic theory suggests you should value mortgage derivatives on the basis that house prices would always rise. Finance professors are not to blame for this, but they might have shouted more loudly that their insights were being misused. Instead many cheered the party along (often from within banks). Put that together with the complacency of the macroeconomists and there were too few voices shouting stop.  ­

警告如此多。但是，当学术界的见解传达到华尔街的激烈竞争中时，这些金玉良言却被冷落一旁。而荒唐的假设却被添加进来。没有经济理论告诉你要以房价会一直上涨为基础来衡量抵押衍生物的价值。金融专家不应为此受到指责，但在他们的观点被曲解时，他们应该更大声的喊出来。相反，很多专家却一直鼓励当事人（一般和银行有关）。加上宏观经济学家的自满，就很少有声音呼吁停止了。­

Blindsided and divided ­

井底之蛙­

The charge that most economists failed to see the crisis coming also has merit. To be sure, some warned of trouble. The likes of Robert Shiller of Yale, Nouriel Roubini of New York University and the team at the Bank for International Settlements are now famous for their prescience. But most were blindsided. And even worrywarts who felt something was amiss had no idea of how bad the consequences would be. ­

指责大多数经济学家没有察觉危机的来临也有好处。不可否认，有些人为经济危机做出了警告。比如耶鲁（Yale）的罗伯特·希勒（Robert Shiller），纽约大学（New York University ）的努里尔鲁比尼（Nouriel Roubini ）以及银行里的国际清算团队，现在，因为他们的先见之明，他们出名了。但大多数人还是不知所措。即使那些杞人忧天者也不知道经济危机的结果会有多坏。­

That was partly to do with professional silos, which limited both the tools available and the imaginations of the practitioners. Few financial economists thought much about illiquidity or counterparty risk, for instance, because their standard models ignore it; and few worried about the effect on the overall economy of the markets for all asset classes seizing up simultaneously, since few believed that was possible.  ­

这和专业简仓有部分联系，因为专业简仓制约了实用性的工具和实际工作者的想象力。比如，没有金融经济学家考虑不动产或者交易对方的风险，因为他们的标准模式就忽视了这个；没有人担心所有资产类同时停止运转对市场经济影响，因为没有人相信这种情况会发生。­

Macroeconomists also had a blindspot: their standard models assumed that capital markets work perfectly. Their framework reflected an uneasy truce between the intellectual heirs of Keynes, who accept that economies can fall short of their potential, and purists who hold that supply must always equal demand. The models that epitomise this synthesis—the sort used in many central banks—incorporate imperfections in labour markets (“sticky” wages, for instance, which allow unemployment to rise), but make no room for such blemishes in finance. By assuming that capital markets worked perfectly, macroeconomists were largely able to ignore the economy’s financial plumbing. But models that ignored finance had little chance of spotting a calamity that stemmed from it. ­

宏观经济学家也有一个盲点：他们的标准模式假设资本市场能够良好运转。他们的框架反应了凯恩斯知识继承人和纯粹主义者之间不稳定的调和，凯恩斯承认经济没能发挥他的潜力，而纯粹主义者认为供求必须一致。这种合成缩影出的模式——在很多中央银行使用——合并了劳动力市场里的缺陷（比如导致失业增加的“黏性”工资），却不能容忍金融上的缺陷。宏观经济学家假设资本市场良好运转，他们就很容易忽视金融系统。但是，忽视金融的模式就不可能发现一个由金融引起的灾难。­

What about trying to fix it? Here the financial crisis has blown apart the fragile consensus between purists and Keynesians that monetary policy was the best way to smooth the business cycle. In many countries short-term interest rates are near zero and in a banking crisis monetary policy works less well. With their compromise tool useless, both sides have retreated to their roots, ignoring the other camp’s ideas. Keynesians, such as Mr Krugman, have become uncritical supporters of fiscal stimulus. Purists are vocal opponents. To outsiders, the cacophony underlines the profession’s uselessness. ­

该如何补救呢？金融危机已经把纯粹主义者和凯恩斯主义者脆弱的共识弄没了，只有货币政策才能让商业周期顺畅。很多国家的短期利率接近零，货币政策对银行业的危机见效甚微。随着他们妥协的手段没起作用，双方都固步自封而无视对方的观点。凯恩斯主义者，比如克鲁曼就成了政府财政刺激的坚决拥护者。纯粹主义者口头上反对。对局外人来说，这种不和谐的声音凸显了该行业的无能。­

Add these criticisms together and there is a clear case for reinvention, especially in macroeconomics. Just as the Depression spawned Keynesianism, and the 1970s stagflation fuelled a backlash, creative destruction is already under way. Central banks are busy bolting crude analyses of financial markets onto their workhorse models. Financial economists are studying the way that incentives can skew market efficiency. And today’s dilemmas are prompting new research: which form of fiscal stimulus is most effective? How do you best loosen monetary policy when interest rates are at zero? And so on.  ­

综合这些指责，明显是该进行再发现了，特别是宏观经济学。就像经济大萧条使凯恩斯主义者的大量涌现，二十世纪七十年代的经济停滞与通货膨胀激起了对抗性反应，具有创造性的销毁已经到来。中央银行忙着停止把金融市场映射在他们工作模式这种粗俗分析。金融经济学家研究刺激如何曲解市场效率。今天的困境推动了新的研究：哪种形式的财政刺激最有效果？当利率为零时如何最好的放宽货币政策？等等……­

But a broader change in mindset is still needed. Economists need to reach out from their specialised silos: macroeconomists must understand finance, and finance professors need to think harder about the context within which markets work. And everybody needs to work harder on understanding asset bubbles and what happens when they burst. For in the end economists are social scientists, trying to understand the real world. And the financial crisis has changed that world.  ­

但是心态上更大的改变还是需要的。经济学家需要从他们专业简仓中走出来：宏观经济学家必须懂得金融，金融专家需要思考市场运转的环境。每个人都需要努力去理解资产泡沫以及泡沫破灭的后果。最后，经济学家是社会学家，他们试着去理解真实的世界。金融危机已经改变了世界。­

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