High equity premia and crash fears - Rational foundations

Summary. We show that in a Lucas endowment economy in which the process for dividends is described by a lattice tree subject to infrequent but observable structural breaks, in equilibrium recursive rational learning may inflate the equity risk premium and reduce the risk-free interest rate for low levels of risk aversion. The key condition for these results to obtain is the presence of sufficient initial pessimism. The relevance of these findings is magnified by the fact that under full information our artificial economy cannot generate asset returns matching the empirical evidence for any positive relative risk aversion.Received: 20 September 2003, Revised: 27 April 2005, JEL Classification Numbers: D83, E44, G12.I am indebted to Mordecai Kurz (the co-Editor), one anonymous Referee, Gabriele Camera, Sadayuki Ono, Olesia Verchenko, and Allan Timmermann for many useful comments. I also think seminar paticipants at the European Economic Association meetings in Stockholm (August 2003) and the Midwest Economics Association in St. Louis (March 2003).     

Rationalizable variable-population choice functions

Summary. We analyze the rationalizability of variable-population social-choice functions in a welfarist framework. It is shown that fixed-population rationalizability and a weakening of congruence together are necessary and sufficient for rational choice, given a plausible dominance property that prevents the choice of alternatives involving low utility levels. In addition, a class of critical-level separable choice functions is characterized. This result, which extends an earlier axiomatization of a related class of bargaining solutions to a variable-population setting, is the first axiomatization of critical-level principles in a general choice-theoretic model. Received: November 30, 1999; revised version: September 11, 2000     

7086例Ⅰ类切口手术抗菌药物预防性使用情况

目的调查Ⅰ类切口手术围手术期抗菌药物预防性使用情况,考察临床药师干预效果,为临床合理用药提供参考。方法收集西双版纳州人民医院2016—2018年总计7086例Ⅰ类切口手术,对抗菌药物预防使用率、给药时机、疗程以及品种选择等方面进行分析。结果2016—2018年,Ⅰ类切口手术的抗菌药物预防使用率从12.73%降至8.44%;术前0.5~1 h给药率从89.90%升至97.11%;用药疗程>48 h比例从28.20%降至4.96%;一、二代头孢使用比例从66.54%升至83.06%。不合理用药情况主要集中在骨科、疼痛科等科室。结论通过临床药师有效干预,Ⅰ类切口手术围手术期预防性应用抗菌药物合理性得到了显著改善,但仍有不足,需继续加强监督。     

German Monetary Union: An historical counterfactual analysis

This paper views German Monetary Union as a sequence of large asymmetric shocks to the European economies. As such it can be analysed with a large, new-Keynesian macro-econometric model of the relevant economies such as NiGEM. The ‘news’ in the sequence of shocks is assessed by analysing contemporary, NiGEM based, forecasts, and important events are then ‘peeled-off’ in reverse order. The resulting counterfactual history analyses the effects of the collapse of the Soviet economy on the EC and Scandinavian economies, and it is argued that the recession in countries such as Finland was not primarily caused by trade effects. The costs of support programmes for East Germany are then removed, creating a negative fiscal shock. Finally the paper analyses the overall effects of the set of shocks. In each part of the counterfactual history, individuals from forward looking expectations and the authorities operate fiscal solvency rules and target monetary aggregates.     

制度缺陷与资源配置效率——来自中国股票市场的实证研究

中国股市与生俱来的高波动性是不争的事实,股指暴涨暴跌、个股换手频繁表明股价的波动幅度和交易的频率都远远超过了基本面变动的速度,是过度噪声的直观证据,其内在本质在于中国股市的制度缺陷,尤其是股权集中和股权分置。笔者借鉴Mishkin(1983)和Sloan(1996)的做法,采用理性预期定价模型进行了实证检验。结果发现,尽管从样本期间(1995￣2001)整体来看市场对资源的配置是有效的,但是个别年份却是无效的。这说明中国的制度缺陷确实损害了资源的配置功能。提出制度的缺陷还必须由制度创新来弥补,非流通股的自由公开转让,股权的适度分散是必经之路的论点。     

经济周期波动理论的演进历程及学派研究

对于经济周期波动现象出现的原因,各个经济学流派从不同角度进行了阐释。本文阐述经济周期波动理论研究的演进,分析各个流派理论的产生背景、主要结论和缺陷。对经济周期波动本质原因的研究有益于对我国市场经济体制下经济周期波动的理解,促进我国经济平稳和谐地发展。     

Firms' investments in general training and the skilled labour market

An adverse selection model is analysed, where firms can train or hire a skilled worker. In equilibrium, the market wage is determined by supply and demand. The quality of the supplied skilled labour is negatively biased, because workers stem from firms that shut down and from firms that observed their trainee's bad quality during the training. If fewer firms were to shut down, then the supplied average quality deteriorates and the incentive to train increases. The incentive is inefficient, because firms must share the informational rent and they free-ride. Ex ante workers may wish to increase the firms' bargaining power.     

On the microstructure of price determination and information aggregation with sequential and asymmetric information arrival in an experimental asset market

Summary. Experiments were conducted on an asset with the structure of an option. The information of any individual is limited, as if only the direction of movement of the option value known for a single period without information of the value from when movement was initiated. However, if all information of all insiders were pooled, the value of the option would be known with certainty. The results are the following: (1) Information becomes aggregated in the prices as if fully informative rational expectations operated; and (2) The mechanism through which information gets into the market is captured by a path dependent process that we term The Fundamental Coordination Principle of Information Transfer in Competitive Markets. The early contracts tend to be initiated by insiders who tender limit orders. The emergence of bubbles and mirages in the markets are coincident with failures and circumstances that prevent the operation of the Fundamental Principle.The financial support of the national science foundation and the Caltech Laboratory for Experimental Economics and Political Science are gratefully acknowledged. The authors have benefited from helpful comments of David Grether, Kerry Back, Ivana Komunjer and Pete Kyle.     

Are There Rational Speculative Bubbles in REITs?

This study tests for the presence of rational speculative bubbles in the Equity REIT industry. We analyze REIT prices using a vector of macroeconomic fundamentals. Using the unit root test and cointegration procedures, we find no evidence of rational bubbles in the REIT market. Tests for duration dependence in the returns series show no evidence of negative duration dependence, suggesting that REIT markets are not affected by rational bubbles. Applying the same tests, we find no evidence of rational speculative bubbles in the Russell 2000 index, a proxy for small-cap stocks.     

Economic factors affecting the increase in obesity in the United States: Differential response to price

A sharp increase in obesity during the last 15 years in the United States became one of the nation’s main public health problems. The theory of rational addiction seems to explain human behavior in food consumption leading to obesity reasonably well. The interesting thing about our results is that the tax policy, normally used to correct various distortions, is to serve in this case as the preventive policy: additional taxes on future prices of the addictive (sweet) foods contribute to lower sugar consumption and BMI at present time. On the other hand, increasing education level is usually considered a preventive type of policy. In this case, it leads to lowering the levels of the BMI in already overweight and obese population.