Collaborative Research: Experimental Evidence on Monetary Policies

2008-09年的大衰退导致各国央行尝试了非传统货币政策，例如日本、英国和美国的量化宽松，以及丹麦、瑞典和欧元区的超额准备金负利率。然而，由于需要在可预见的范围内避免这些非传统政策对宏观经济的有害影响，政策试验的程度大大降低。在这个项目中，我们制定了在实验实验室的受控条件下进行更广泛的货币政策实验的议程，目的是在可能的实地实施之前了解各种货币政策的福利后果。我们的方法类似于在飞机被允许飞行之前对飞机进行风洞测试。在必须小规模、低风险、有付费受试者的实验室环境中研究货币政策，比在该领域进行实验的限制性要小得多，成本也要高得多，从而能够评估一套更丰富、甚至更激进的货币政策。事实上，我们的目标是为各种货币政策的福利影响提供新的证据，这些政策即使不是不可能在现场实施，但至少在没有一些关于其有效性的事先证据的情况下是很难实施的。我们寻求开始收集此类证据的进程。我们更大的目标是证明，在评估不同货币政策的有效性时，实验室货币政策测试可以作为理论和现场数据实证分析的补充工具。我们的货币政策分析框架是拉各斯和赖特的货币搜索理论模型，这是我们之前在实验室实施的货币经济学中的一个工作马模型。在这个项目中，我们建议使用拉各斯-赖特模型来探索著名的弗里德曼规则(弗里德曼1969年)的货币政策。众所周知，弗里德曼规则在各种不同的货币模型中都是最优的，包括拉各斯-赖特模型。从本质上讲，弗里德曼指出，福利最大化的货币政策是设定通货膨胀，使名义利率--持有货币的私人边际成本--等于零。由于生产更多货币的社会边际成本基本上为零，如果私人边际成本为正，将存在一个低效缺口，可以通过将名义利率设为零来弥补。由此得出的结论是，如果安全政府债券的实际收益率是ñ0，而费舍尔方程给出的名义利率I是I=Eiñ，其中Ei代表预期通胀率，那么，为了让I=0，央行应该努力设置Ei=-ñ0。尽管央行行长们无疑意识到了弗里德曼规则，并经常表达出对低通胀的真诚愿望，但央行官员主张负通胀率(通缩)是非常违反传统智慧的，更不用说像弗里德曼规则通常所要求的那样试图实施了。在实验室里，我们不受这些考虑的约束，因此，我们建议以两种不同的方式实施弗里德曼规则，并评估其对福利的影响。第一种方法是上述类型的通货紧缩货币政策。第二种方法是为持有货币支付具有竞争力的市场利率，完全消除私人持有货币的边际成本。与第一种方法一样，为手中现金持有量提供利息的可行性很可能使这种可能性变得不可行。在这个项目中，我们首次探索了弗里德曼规则在我们实验性的拉各斯-赖特经济中的两种实现。除了探索弗里德曼规则的两种不同实施方式的福利后果外，我们还有兴趣使用我们的框架来研究通胀政策的福利后果。具体地说，我们对低通货膨胀率和高通货膨胀率的福利成本感兴趣，我们建议通过改变货币增长率来解决这个问题。最后，根据我们之前的一项研究，我们希望研究对法定货币使用(例如纳税)的法律限制是否对采用法定货币和福利有影响。

The Great Recession of 2008-09 led central banks to experiment with non-traditional monetary policies, for example, quantitative easing in Japan, the U.K. and the U.S. and negative interest rates on excess reserves in Denmark, Sweden and the Eurozone. Nevertheless, the extent of policy experimentation was greatly tempered by the need to avoid, to the extent foreseeable, harmful macroeconomic impacts from these non-traditional policies. In this project we set out an agenda for conducting monetary policy experiments more broadly in the controlled conditions of the experimental laboratory with the aim of understanding the welfare consequences of various monetary policies prior to their possible implementation in the field. Our approach is analogous to wind-tunnel testing of aircraft before the aircraft is allowed to fly. The study of monetary policies in the necessarily small-scale, low-stakes laboratory environment with paid human subjects is much less restrictive or expensive than experimentation in the field, thereby allowing for evaluation of a much richer and even radical set of monetary policies. Indeed, our aim is to provide new evidence on the welfare impacts of various monetary policies that would be difficult, if not impossible to implement in the field at least without some prior evidence on their effectiveness. We seek to begin the process of gathering such evidence. Our larger goal is to demonstrate that laboratory tests of monetary policies can be a complementary tool to theory and empirical analysis of field data in the evaluation of the efficacy of different monetary policies.Our framework for monetary policy analysis is Lagos and Wright's search-theoretic model of money, a work-horse model in monetary economics that we have previously implemented in the laboratory. In this project we propose to use the Lagos-Wright model to explore the celebrated Friedman rule (Friedman 1969) for monetary policy. The Friedman rule is known to be optimal in a very wide variety of different monetary models, including the Lagos-Wright model. In essence, Friedman showed that the welfare-maximizing monetary policy is to set inflation so as to make the nominal interest rate - the private marginal cost of holding money -- equal to zero. Since the social marginal cost of producing more money is essentially zero, if the private marginal cost were positive, there would be an inefficient gap that could be closed by making the nominal interest rate equal to zero. It follows that, if the real rate of return on safe government bonds is ñ0, and the nominal interest rate, i, as given by the Fisher equation, is i= EI + ñ, where EI denotes the expected inflation rate, then, in order for i=0 the central bank should work to set EI = -ñ 0. While central bankers are undoubtedly aware of the Friedman rule and often express a genuine desire for low inflation, it would be very much against conventional wisdom for central bankers to argue for, let alone attempt to implement, a negative inflation rate (deflation) as the Friedman rule would typically require. In the laboratory we are not bound by such considerations and thus we propose to implement the Friedman rule in two different ways and assess the welfare implications. The first approach is a deflationary monetary policy of the type outlined above. The second approach is to pay a competitive market interest rate on money holdings removing altogether the private marginal cost from holding money. As with the first approach, the practicalities of providing interest on hand-to-hand cash holdings has likely rendered this possibility unworkable. In this project we explore, for the first time both implementations of the Friedman rule in our experimental Lagos-Wright economy. In addition to exploring the welfare consequences of the two different implementations of the Friedman rule, we are also interested in using our framework to study the welfare consequences of inflationary policies. Specifically, we are interested in the welfare costs of low versus high inflation rates, and we propose to address this question by varying the money growth rate. Finally, following up on one of our previous studies, we wish to study whether legal restrictions on the use of fiat money (e.g. to pay taxes) matter for the adoption of fiat money and for welfare.