Raghuram Rajan Raghuram Rajan
Raghuram Rajan, a former chief economist of the IMF, is Professor of Finance at the University of Chicago and the author of Fault Lines: How Hidden Fractures Still Threaten the World Economy
经济学家为何无法预测危机经济学家为何无法预测危机？？
发自芝加哥——在经济危机最高峰之时，英女王伊丽莎白二世向我那些伦敦经济学院的友人们提出了一个简单却又无法轻易回答的问题：专业经济学家为何没能预测这场危机？
对此其实有几种答案。一是说经济学家缺少相关模型，因此也无法对导致本次危机的行为作出解释。另一种认为经济学家都被无限制自由市场的教条思想蒙住了眼睛，觉得这样的市场是不会出错的。而最后一种逐渐流行的说法则是经济学家都收受了金融系统的好处，于是集体保持沉默。
在我看来，真相另有所在。
实际上，我们这些专业经济学家并不缺乏有用的模型去解释这些状况。如果你认为危机的成因是缺乏流动性，我们有一大堆模型可以分析流动性短缺及其对金融机构的影响。如果你觉得始作俑者是贪婪的银行家和盲从的投资者，是这些人在政府援
助方案的包庇或是市场非理性繁荣的疯狂驱动下胡作非为，我们对此也有极为细致深入研究。
经济学家们甚至分析了监管和去监管两者之间的政治经济效应，因此也深知为何某些美国政客极力推动私人部门发放住房贷款，另一些却着手去除对私人金融活动的监管。但让人困惑的是经济学家们竟没有将这些认识转化为结论，并集体发出警告。
与理念有关的：我们都过分固执地认为市场是有效的，市场参或许这样做的理由是与理念有关的
与理念有关的
环纹
与者是理性的，而高价格是可以用经济法则来解释的。而某些对这种“市场原教旨主义”的批评则反映了一种错误的理解。当前主流的“有效市场管理论”只是说市场反映了公众所知的信息，也难以持续地从市场中赚钱——我们从某些投资者在危机中遭重创的投资组合中可以发现这点。但该理论可没有说市场在碰到坏消息或是投资者变得厌恶风险时不会大幅下挫。
盛夏是几月有批评认为经济法则的失效显而易见，但市场（以及经济学家）却对此视而不见。但这都是马后炮。我们不能单凭一个像耶鲁大学的罗伯特·席勒（此君一直认为高房价是无法维持的）那样的孤独预言家就认为真相被忽视了。凡事都有唱反调的人，而且这些人经常是错的。相比之下，有更多的经济学家认为房价虽然很高，但却不可能全盘下跌。
当然，这些预期都会被理念所扭曲——但我们也无从追查经济学家们过去是如何思考的。而那些将原因单纯归咎于某种理念的解释也是站不住脚的，须知作为一个群体，无论是那些将市场效率视为笑话的行为经济学家；还是不相信自由市场的发展经济学家，都没能预测到这场危机。
幸运草那么这其中是否还存在腐败呢？有些专业经济学家在银行或评级机构担任顾问，在投资者讲座上发言，扮演专家证人的角色，还拿着别人的钱做研究。这令公众很自然地怀疑我们是否有偏袒之处。同时这种偏向性可以是隐性的：我们的世界观就是由那些金融界友人的信仰塑造出来的；也可以是显性的：一个经济学家可能会撰写一份符合资助者心意的报告，或者纯粹为挣钱而发表证言。
鹿茸片的正确吃法
有足够的事例可以证实这种潜在的偏向性，因此也无法忽视这一问题。其中一个解决方案就是断绝经济学家与金融企业之间的所有联系。但如果经济学家都被关在了象牙塔里，我们可能会变得客观，但却更加与实际情况脱节——并因此更加无法预测危机，另一种恢复信心的方式则是信息披露制度——比如说经济学家必须声明在某项特定分析中所获取的货币利益，或者更简单地说，告诉大家是谁给了我们钱。事实上有一些大学已经开始推进这方面事务了。
但我相信腐败并非经济学家无法识别危机的主因。大多数经济学家都与企业交往甚少，而那些“不偏心的”经济学家也无法预测这场危机。
在此我认为有三个因素能大概解释经济学家集体出错的原因：高度专业化，预测的难度，以及大部分经济学科与现实的脱节。
跟医学一样，经济学也被划分成许多不同的门类——宏观经济学家一般不会关注金融经济学家或地产经济学家究竟在干什么，反之亦然。但预测危机却需要对各个经济学领域都有所涉猎的人——正如我们需要一个优秀的全科医师去辨认某种外来病一样。由于该学科只崇尚细致，证据充分但也必然有些狭窄的研究，因此也只有少数的经济学家愿意在各细分领域之间进行跨界研究。
但即便他们这样做了，他们也会羞于预测。专业经济学家相对于专业市场预测者的主要优势可能在于前者更容易意识到各因素之间已经建立的关联。而预测的最困难之处恰恰是转折点——就是当旧有的
关联破裂之时。虽然有些因素会反映转折点的到来——比如说短期金融杠杆和资产价格的上升通常预示着泡沫破裂——但这不意味着危机就一定会爆发。
专业上对跨领域研究的轻视，再加上预测的低准确性以及可能给名誉带来的损失，都让大多数专业经济学家对预测敬而远之，也导致专业经济学家甚少对短期经济活动发表意见，因此预测这件动辄得咎的事情只好留给专业预测者去做了。
但这也暴露了其中的危机：对短期经济发展状况的怠慢导致专业经济学家忽略了他们有资格发表意见的中期趋势。如果是这样的话，引发这些经济学家们误判危机的真正原因就不是不恰当模型，理念误区或者腐败这类高深的理由，而是一个更平淡无奇但也更令人忧心不已的事实：许多经济学家根本就没有关注与危机有关的一切！
拉古兰拉古兰··拉贾拉贾，，芝加哥大学布斯商学院经济学教授芝加哥大学布斯商学院经济学教授，，著有著有《《断层断层：：隐藏的隐藏的断裂是如何断裂是如何持续威胁世界经济的持续威胁世界经济的》》一书一书。。
Why Did Economists Not Foree the Crisis? Raghuram Rajan
梦见自己给自己剪头发是什么意思
CHICAGO – At the height of the financial crisis, the Queen of England asked my friends at the London School of Economics a simple question, but one for which there is no easy answer: Why did academic economists fail to foree the crisis?
诸葛亮死在哪里
Several respons to that query exist. One is that economists lacked models that could account for the behavior that led to the crisis. Another is that economists were blinkered by an ideology according to which a free and unfettered market could do no wrong. Finally, an answer that is gaining ground is that the system bribed economists to stay silent.
In my view, the truth lies elwhere.
It is not true that we academics did not have uful models to explain what happened. If you believe that the crisis was caud by a shortage of liquidity, we had plenty of models analyzing liquidity short
ages and their effects on financial institutions. If you believe that the blame lies with greedy bankers and unthinking investors, lulled by the promi of a government bailout, or with a market driven crazy by irrational exuberance, we had studied all this too, in great detail.
Economists even analyzed the political economy of regulation and deregulation, so we could have understood why some US politicians pushed the private ctor into financing affordable housing, while others deregulated private finance. Yet, somehow, we did not bring all this understanding to bear and collectively shout our warnings.
Perhaps the reason was ideology: we were too wedded to the idea that markets are efficient, market participants are rational, and high prices are justified by economic fundamentals. But some of this criticism of “market fundamentalism” reflects a misunderstanding. The
dominant “efficient markets theory” says only that markets reflect what is publicly known, and that it is hard to make money off markets consistently – something verified by the hit that most investor portfolios took in the crisis. The theory does not say that markets cannot plummet if the news is bad, or if investors become risk-aver.
压力感不可控制
Critics argue that the fundamentals were deteriorating in plain sight, and that the market (and econo
mists) ignored it. But hindsight distorts analysis. We cannot point to a lonely Cassandra like Robert Shiller of Yale University, who regularly argued that hou prices were unsustainable, as proof that the truth was ignored. There are always naysayers, and they are often wrong. There were many more economists who believed that hou prices, though high, were unlikely to fall across the board.
Of cour, the expectations could have been distorted by ideology – it is hard to get into the past minds of economists. But there is a better reason to be skeptical of explanations relying on ideology. As a group, neither behavioral economists, who think that market efficiency is a joke, nor progressive economists, who distrust free markets, predicted the crisis.
Could it be corruption? Some academic economists consult for banks or rating agencies, give speeches to investor conferences, rve as expert witness, and carry out sponsored rearch. It would be natural to suspect us of bias. The bias could be implicit: our worldview is shaped by what our friends in industry believe. Or it may be an explicit bias: an economist might write a report that is influenced by what a sponsor wants to hear, or give testimony that is purely mercenary.
There are enough instances of possible bias that the issue cannot be ignored. One remedy would be to ban all interaction between economists and the corporate world. But if economists were confined t
o the ivory tower, we might be unbiad, but we would also be ignorant of practicalities – and thus even less capable of predicting problems. One way to restore trust may be disclosure – for economists to declare a monetary interest in a particular analysis and, more generally, to explain who pays us. A number of universities are moving in this direction.
But I believe that corruption is not the main reason that the profession misd the crisis. Most economists have very little interaction with the corporate world, and the “unbiad” economists were no better at forecasting the crisis.写李白的诗
I would argue that three factors largely explain our collective failure: specialization, the difficulty of forecasting, and the dingagement of much of the profession from the real world.
Like medicine, economics has become highly compartmentalized – macroeconomists typically do not pay attention to what financial economists or real-estate economists study, and
