Rethinking Macroeconomics: What Went Wrong and How to Fix It
Rethinking Macroeconomics: What Went Wrong and How to Fix It
复制标题
重新思考宏观经济学：出了什么问题以及如何解决
DOI：
10.1111/j.1758-5899.2011.00095.x
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发表时间：
2011
期刊：
影响因子：
1.9
通讯作者：
J. Stiglitz
中科院分区：
文献类型：
--
作者：
J. Stiglitz
摘要
金融危机暴露了标准宏观经济模型的缺陷，这些模型不仅没有预测到危机，而且还说这种事件不可能发生。虽然人们早就知道，市场在一般情况下是没有效率的，例如在信息不完善的情况下，但标准模型侧重于没有出现随之而来的问题的特殊情况。当市场不完善被引入时，它是以特别的方式进行的，并且/或者不能充分解释深度衰退，例如大衰退。这篇文章描绘了标准模型的失败，并将导致危机的政策失败及其管理与该模型的影响联系起来。标准模型专注于解释正常波动，而真正重要的是理解是什么导致了深度衰退，为什么对系统的冲击会如此放大，以及为什么从这些事件中恢复如此缓慢。(The标准模型假定经济受到外部冲击的冲击;然而，大多数危机冲击是内部的-“人为的”。本文提出了四个假设，说明经济结构如何改变（有时是政策的结果），从而增加了大规模崩溃和缓慢复苏的可能性。最后，本文解释了为什么在当前背景下，从标准模型得出的政策处方可能会产生误导。
政策影响
·危机前货币政策的重点--保持低通胀和稳定--显然不足以维持真实的稳定。 未来，货币当局需要更加关注影响金融体系稳定和信贷投放的因素。与严重衰退相关的损失相比，与低通胀或温和通胀相关的相对价格轻微失调相关的无谓损失微不足道。
·除了利率之外，中央银行还可以使用各种各样的监管工具。 如果他们运用得当，造成当前危机的泡沫本可以被抑制，泡沫破裂的经济后果也会减轻。虽然使用这些工具可能会产生一些成本，但与不使用它们的成本相比，这些成本微不足道-因为美国经济衰退的成本高达数万亿美元。
·这将需要更多地关注银行系统的行为，包括严格的监督和监管，旨在防止过度冒险和过度互联，并鼓励银行专注于贷款，特别是对中小企业的贷款，这些企业通常无法进入资本市场。 例如，在决定投资方面，特别是对中小企业来说，信贷供应可能与利率同样重要，甚至比利率更重要。
·这场危机是美国近年来采取的金融市场自由化措施的后续，这并不奇怪;金融危机经常伴随着这种自由化。 在全球范围内，金融和资本市场的自由化使“美国制造”的危机蔓延到世界各地。
·住房抵押贷款证券化的内在问题意味着政府不应该指望市场的恢复--除非它得到了被视为不可接受的政府担保的支持。 相反，应该回归更传统的抵押贷款制度（基于银行或丹麦抵押贷款制度）。
·财政政策可以成为降低失业率和恢复增长的有效机制，即使在适度的国家债务水平下也是如此。 精心设计的计划可以同时减少长期债务。相比之下，在利率接近于零的情况下，紧缩政策的收缩效应无法被宽松的货币政策抵消。
·许多成为宏观经济学标准的模型并没有包含一些特征，这些特征使它们能够预测经济衰退（它们认为这种事件不可能发生），采取行动防止这种衰退或在危机发生时做出反应。 许多宏观经济学是不连贯的-使用一套模型，一套强有力的假设，来倡导资本和金融市场自由化，而另一套模型则用来应对这种自由化往往带来的危机。在企业和家庭不面临财务约束和过度杠杆的时期，以及中央银行能够轻松提高和降低利率的时期，模型估计不一定能为当前这样的深度衰退中的行为反应提供足够的指导。
·虽然确定对当前政府政策的动态反应很重要，但需要纳入更广泛的反应。 长期失业以及教育和基础设施投资不足可能会影响未来的增长和生产力。
Abstract
The financial crisis made obvious the deficiencies in the standard macroeconomic models, which not only did not predict the crisis, but also said that such events could not occur. While it has long been known that markets are not in general efficient, for example with imperfect information, standard models focused on special cases where the consequent problems did not arise. When market imperfections were introduced, it was done in ways that were ad hoc and/or did not adequately explain deep downturns, such as the Great Recession. This article charts the failures of the standard model, and relates policy failures in the lead-up to the crisis as well as its management to that model’s influence. The standard models focused on providing explanations of normal fluctuations, when what really matters is understanding what causes deep downturns, why shocks to the system get so amplified and why recovery from such events is so slow. (The standard models assumed that the economy was buffeted by exogenous shocks; most crisis shocks are, however, endogenous –‘manmade’.) Four hypotheses are presented about how the structure of the economy changed (sometimes as a result of policy) in ways that increased the likelihood of a large crash with a slow recovery. Finally, the article explains why, in the current context, the policy prescriptions derived from standard models are likely to be misleading.
Policy Implications
• The focus of monetary policy before the crisis – keeping inflation low and stable – clearly did not suffice to maintain real stability. In the future, monetary authorities need to focus more on the factors that affect the stability of the financial system and credit supply. The deadweight losses associated with the slight misalignment of relative prices associated with low or moderate inflation are miniscule compared to the losses associated with a deep recession.
• Central banks have at their disposal, in addition to interest rates, a wide range of regulatory instruments. Had they employed these properly, the bubble that caused the current crisis could have been dampened, and the economic consequences of its breaking mitigated. While there may be some costs associated with the use of these instruments, these pale in comparison to the costs of not using them – as the costs of the downturn in the US mount into the trillions.
• This will necessitate paying more attention to the behavior of the banking system – including tight supervision and regulations, designed to prevent excessive risk taking and excessive interconnectivity, and to encourage banks to focus on lending, especially to small and medium-sized enterprises, which typically do not have access to capital markets. Credit availability may be as important as or more important than interest rates in determining, for instance, investment, especially for SMEs.
• It is not a surprise that this crisis followed on from financial market liberalization measures taken by the US in recent years; financial crises frequently follow such liberalizations. Globally, financial and capital market liberalizations enabled the ‘made in America’ crisis to spread all over the world.
• Inherent problems in securitization of home mortgages mean that governments should not count on the restoration of that market – unless it is underpinned with what should be viewed as unacceptable government guarantees. Rather, there should be a return to more traditional mortgage systems (bank based, or the Danish mortgage system).
• Fiscal policies can be an effective mechanism for reducing unemployment and restoring growth, even in the presence of moderate levels of national debt. Well-designed programs can simultaneously reduce the debt over the long run. By contrast, with interest rates near zero, the contractionary effects of austerity policies cannot be offset by looser monetary policies.
• Many of the models that became standard in macroeconomics did not incorporate features that allowed them to forecast the downturn (they suggested that such events could not occur), to take actions to prevent such downturns or to respond to the crisis once it occurred. Much of macroeconomics was incoherent – using one set of models, with one set of strong assumptions, to advocate for capital and financial market liberalization, and another set of models to respond to the crises that often follow on from such liberalizations. Models estimated in periods in which firms and households do not face financial constraints and excessive leverage and where central banks are able both to raise and lower interest rates easily do not necessarily provide adequate guidance for behavioral responses in the midst of a deep downturn such as the current one.
• While it is important to ascertain dynamic responses to current government policies, a wider range of responses needs to be incorporated. Extended periods of unemployment and underinvestment in education and infrastructure can impact future growth and productivity.