Monotone risk aversion

Summary. This paper defines decreasing absolute risk aversion in purely behavioral terms without any assumption of differentiability and shows that a strictly increasing and risk averse utility function with decreasing absolute risk aversion is necessarily differentiable with an absolutely continuous derivative. A risk averse utility function has decreasing absolute risk aversion if and only if it has a decreasing absolute risk aversion density, and if and only if the cumulative absolute risk aversion function is increasing and concave. This leads to a characterization of all such utility functions. Analogues of these results also hold for increasing absolute and for increasing and decreasing relative risk aversion.Received: 31 January 2003, Revised: 15 January 2004, JEL Classification Numbers: D81.The views, thoughts and opinions expressed in this paper are those of the author in his individual capacity and should not in any way be attributed to Morgan Stanley or to Lars Tyge Nielsen as a representative, officer, or employee of Morgan Stanley.     

A simple mean–dispersion model of ambiguity attitudes

Several characterizations of ambiguity aversion decompose preferences into the expected utility of an act and an adjustment factor, an ambiguity index, or a dispersion function. In each of these cases, the adjustment factor has very little structure imposed on it, and thus these models provide little guidance as to which function to use from the infinite class of possible alternatives. In this paper, we provide a simple axiomatic characterization of mean–dispersion preferences which uniquely determines a subjective probability distribution over a set of possible priors and which uniquely identifies the dispersion function. We provide an algorithm for determining this subjective probability distribution and the coefficient in the dispersion function from experimental data. We also demonstrate that the model accommodates ambiguity aversion in the Ellsberg paradox.     

Joint Determination of Current Classroom Performance and Additional Economics Classes: A Binary/Continuous Model

Students in DEEP high schools are found to score higher on the Test of Economic Literacy but are less likely to want another course in economics than students who are not in DEEP schools.     

Behavioral currency hedging for international portfolios

The purpose of this paper is to incorporate behavioral issues as it relates to the active currency hedging of international portfolios in the context of traditional expected utility maximization approach. The uniqueness of the approach is that separate risk aversion parameters are introduced for asset and currency markets. The paper is similar in spirit to Black (Black, F. 1989, Universal hedging, Financial Analysts Journal (July-August), 16-22.), who argued that a portion of foreign equity investments should be permanently unhedged, which is basically postulating that one should take a buy-and-hold position in currency with a fraction of the capital. The behavioral twist included in the traditional expected utility maximization approach results in lower hedge ratios, ceteris paribus, partly due to the asymmetric nature of the compensation structure of currency managers.Since the asymmetric nature of incentive schemes of asset and currency managers dictates how one optimizes the investment portfolio of a pension or endowment fund, the unusual behavior of a given institutional fund manager should not be called “irrational,” only because the optimal currency hedging level deviates from the one derived under rational expectations. This only justifies the use of different hedging strategies by various institutional investors. We describe in detail how the level of hedging should be revised downwards because of behavioral factors. Conclusions are in the context of what people would predict to see in the market, if certain investors behave in an “irrational” way.     

Order and price in a sequential auction

A sequential auction of commercial properties produced evidence that bid timing matters. Prices declined as the auction proceeded, an outcome consistent with expectations when bidders are either risk averse or quantity constrained.     

A Model of Return Volatility with Application to Estimating Relative Risk Aversion

We estimate a monthly return volatility model that allows for the abrupt changes in volatility often observed in returns data. Using this model we are able to identify key months likely to correspond to draws from a high volatility regime. Using our model in conjunction with Merton's (1980) model relating expected risk premia to risk we obtain reasonable estimates of the coefficient of relative risk aversion.     

我国城乡社会保障均等化的评价与对策研究

当前我国社会保障处于非均衡发展状态,不同区域之间、城乡之间、群体之间仍旧存在社会保障的失衡。促进城乡社会保障均等化不仅是改善民生的题中之义,也是构建社会主义和谐社会的现实路径。使用变异系数、基尼系数和泰尔指数等方法测算我国城乡社会保障的均等化程度,客观反映社会保障的城乡差距,据此提出促进城乡社会保障均等化的对策建议,切实保障农村居民和城市居民平等接受社会保障服务的权利,实现我国社会公平。