Ambiguity Made Precise: A Comparative Foundation

The theory of subjective expected utility has been recently extended to allow ambiguity to matter for choice. We propose a notion of absolute ambiguity aversion by building on a notion of comparative ambiguity aversion. We characterize it for a preference model which encompasses some of the most popular models in the literature. We next build on these ideas to provide a definition of unambiguous act and event and show the characterization of the latter. As an illustration, we consider the classical Ellsberg 3-color urn problem and find that the notions developed in the paper provide intuitive answers. Journal of Economic Literature Classification Number: D81.     

Background risk in generalized expected utility theory

Summary. In this paper, it is shown that, for a wide range of risk-averse generalized expected utility preferences, independent risks are complementary, contrary to the results for expected utility preferences satisfying conditions such as proper and standard risk aversion. Received: August 10, 2001; revised version: June 18, 2002 RID="*" ID="*"I thank Simon Grant and an anonymous referee for helpful comments and criticism. This research was supported by an Australian Research Council Senior Fellowship and Australian Research Council Large Grant A79800678.     

Another Look at the Equity Risk Premium Puzzle

The model of Mehra and Prescott (1985, J. Econometrics, 22, 145–161) implies that reasonable coefficients of risk‐aversion of economic agents cannot explain the equity risk premium generated by financial markets. This discrepancy is hitherto regarded as a major financial puzzle. We propose an alternative model to explain the equity premium. For normally distributed returns and for returns far away from normality (but still light tailed), realistic equity risk premia do not imply puzzlingly high risk aversions. Following our approach, the ‘equity premium puzzle’ does not exist. We also consider fat‐tailed return distributions and show that Pareto tails are incompatible with constant relative risk aversion.     

Quantifying the Subjective Value of Certainty

Traditional measures of risk preference require that an agent's utility function be twice differentiable and that the risk be miniscule. We introduce a discrete index that requires no assumptions regarding the functional form of utility or the magnitude of the risk. The index quantifies the value of certainty by contrasting the relief that one experiences from the absence of a loss to the regret that (s)he feels at a foregone opportunity for gain. It exhibits a consistent range across different data types, and signals any economically irrational behavior. Empirical estimates are made with reservation price data and reservation probability data.     

More pessimism than greediness: a characterization of monotone risk aversion in the rank-dependent expected utility model

Summary. This paper studies monotone risk aversion, the aversion to monotone, mean-preserving increase in risk (Quiggin [21]), in the Rank Dependent Expected Utility (RDEU) model. This model replaces expected utility by another functional, characterized by two functions, a utility function u in conjunction with a probability-perception function f. Monotone mean-preserving increases in risk are closely related to the notion of comparative dispersion introduced by Bickel and Lehmann [3,4] in Non-parametric Statistics. We present a characterization of the pairs (u,f) of monotone risk averse decision makers, based on an index of greediness G _u of the utility function u and an index of pessimism P _f of the probability perception function f: the decision maker is monotone risk averse if and only if . The index of greediness (non-concavity) of u is the supremum of taken over . The index of pessimism of f is the infimum of taken over 0 < v < 1. Thus, , with G _u = 1 iff u is concave. If then , i.e., f is majorized by the identity function. Since P _f = 1 for Expected Utility maximizers, forces u to be concave in this case; thus, the characterization of risk aversion as is a direct generalization from EU to RDEU. A novel element is that concavity of u is not necessary. In fact, u must be concave only if P _f = 1.Received: 10 April 2001, Revised: 18 November 2003, JEL Classification Numbers: D81. Correspondence to: Michéle CohenAlain Chateauneuf, Michéle Cohen, Isaac Meilijson: We are most grateful to Mark Machina, Peter Wakker and two anonymous referees for very helpful suggestions and comments.     

Optimal hedge ratio under a subjective re-weighting of the original measure

In this article we study a risk-minimizing hedge ratio with futures contracts, where the risk of the hedged portfolio is measured through a spectral risk measure (SRM), thus incorporating the degree of agent’s risk aversion. We empirically estimate the optimal hedge ratio (OHR) using a long time series of UK and US equity indices, the EURUSD and EURGBP exchange rates and four liquid commodities (Brent crude oil, corn, gold and copper), to represent different asset classes. Comparing the results with common OHRs (such as the minimum variance and the minimum expected shortfall), we find that the agent’s risk aversion has a material impact, and should not be ignored in risk management.     

Normative ecological rationality: normative rationality in the fast-and-frugal-heuristics research program

The purpose of this paper is to examine the normative interpretation of the fast-and-frugal research program and in particular to contrast it with the normative reading of rational choice theory and behavioral economics. The ecological rationality of fast-and-frugal heuristics is admittedly a form of normative naturalism (Gigerenzer and Sturm 2012) – it derives what agents “ought” to do from that which “is” ecologically rational – and the paper will examine how this differs from the normative rationality associated with rational choice theory. I will also attempt to assess the relative adequacy of normative ecological rationality.     

Risk Attitudes of Children and Adults: Choices Over Small and Large Probability Gains and Losses

In this paper we examine how risk attitudes change with age. We present participants from age 5 to 64 with choices between simple gambles and the expected value of the gambles. The gambles are over both gains and losses, and vary in the probability of the non-zero payoff. Surprisingly, we find that many participants are risk seeking when faced with high-probability prospects over gains and risk averse when faced with small-probability prospects. Over losses we find the exact opposite. Children's choices are consistent with the underweighting of low-probability events and the overweighting of high-probability ones. This tendency diminishes with age, and on average adults appear to use the objective probability when evaluating risky prospects.     

How Politicians Make Decisions: A Political Choice Experiment

The present paper reports on a political choice experiment with elected real-world politicians. A questionnaire on political and public issues is used to examine whether prospect theory predicts the responses of experts from the field better than rational choice theory. The results indicate that framing effects do not disappear with expertise.      

A New Look at Old Issues: Keynesian Unemployment Revisited

Economists have long sensed that the failure of goods markets to clear is a prime reason for the emergence of unemployment. The novel feature of this paper is that it discovers a new theoretical basis proving this assumption. The paper claims that in a permanently growing economy, unemployment may be due to the failure of the markets to provide consumers with ever‐new varieties of consumption goods. As the difference between desired and available product widens, effective demand declines, leading on the one hand to unemployment, which exhibits a decisive Keynesian flavour as it is the result of goods markets failures, and on the other hand to an increase in involuntary savings, which provide the financial basis to foster innovation and growth. As the higher growth rate increases the probability of failures in effective demand, it further increases unemployment and increases involuntary savings, resulting in a finite multiplier process.     

Australian Business Investment: A New Look at the Neoclassical Approach*

This paper attempts to reconcile neoclassical theory with Australian investment data. We argue that, by focusing almost exclusively on the demand for capital services, neoclassical investment theory neglects two related decisions: the decision to own the existing capital stock, and the decision to produce new capital goods. We propose a simple model of investment behaviour that integrates production decisions with portfolio decisions. Careful consideration is given to the determination of the price of capital, the rental price of capital, and the return on capital. The model is estimated by FIML, and a number of simulation results are reported.     

Current Accounts and Exchange Rates: A New Look at the Evidence

A small literature has developed exploring nonlinearities in exchange rate data. This paper studies bivariate statistical relationships between current accounts, exchange rates, and cross–country ratios of GDP. The analysis differs from previous empirical work on these issues in using nonparametric methods to allow for nonlinearities, in employing a minimum of statistical assumptions, and in focusing on a fundamental characterization of the data. The authors present new evidence on the connections between exchange rates, the current account, and GDP. While the evidence loosely supports some common beliefs about the data, it conflicts with some common theoretical models. Thus the results pose new challenges for theory.     

A new interpretation for the precautionary saving motive: a note

This paper proposes a new interpretation for the precautionary saving motive: when future income is uncertain, agents increase saving in order to cause a reduction in the disutility due to uncertainty. Furthermore, the paper shows that the usual necessary and sufficient condition for precautionary saving is the condition ensuring this effect to occur and gives new insights into the relationship between risk aversion indexes and precautionary saving.      

Expected utility theory with imprecise probability perception: explaining preference reversals

This article presents a new model for decision-making under risk, which provides an explanation for empirically-observed preference reversals. Central to the theory is the incorporation of probability perception imprecision, which arises because of individuals’ vague understanding of numerical probabilities. We combine this concept with the use of the Alpha EU model and construct a simple model which helps us to understand anomalies, such as preference reversals and valuation gaps, discovered in the experimental economics literature, that standard models cannot explain.     

从博弈看审计独立性威胁

本文从审计行业被赋予的社会责任谈起,分析审计师独立性受到威胁的客观现象,认为审计独立性威胁存在的客观基础在于被审计人掌握审计师选聘权,在此基础上进行的博弈分析,逐步推导出博弈均衡状态,并对博弈结果所蕴含的经济含义与政策含义进行分析与揭示,以期抛砖引玉,为我国审计行业的发展及监管提供新的思路与视角.     

风险度量的经济学理性与风险度量方法比较

本文引入风险度量的经济学理性概念:一种风险度量方法为经济学理性的是指,这种方法对风险的度量结果与经济学中理性人对风险的排序结果相一致,采用这种方法度量风险的决策者,其决策结果也是经济学理性的。本文从风险状态下的决策理论出发,论证了在银行监管问题上,经济学理性的风险度量方法需要满足的条件。结合银行资本充足率监管的演进趋势,比较了几种重要的风险度量方法,并提出了一种经济学理性的、符合银行监管需要的风险度量方法。     

Evaluation periods and asset prices: Myopic loss aversion at the financial marketplace

Examining myopic loss aversion (MLA [Benartzi, S., Thaler, R., 1995. Myopic loss aversion and the equity premium puzzle. Quarterly Journal of Economics 110, 73–92]) in real financial markets has several merits: in repeated situations investors may learn from each other, aggregate market prices may eliminate individual violations of expected utility, and individuals may decide differently in real situations than in laboratories. We utilize a special feature at the Tel Aviv stock exchange (TASE): occasional shifts of securities from daily to weekly trading. If investors’ decisions are influenced by trading frequency manipulation, then returns should be predictably affected. MLA results in a negative relation between risk aversion and the length of the evaluation period. Thus, the longer the evaluation period is, the lower the expected return is. This intuition also suggests reduced sensitivity to economic events in longer evaluation periods. We find strong support for MLA in the marketplace when testing expected return, as well as return sensitivity.     

A New Look at Intergenerational Mobility in Germany Compared to the U.S

Motivated by contradictory evidence on intergenerational mobility in Germany, I present a cross‐country comparison of Germany and the U.S., reassessing the question of whether intergenerational mobility is higher in Germany than in the U.S. I can reproduce the standard result from the literature, which states that the German intergenerational elasticity estimates are lower than those for the U.S. However, based on highly comparable data, even a reasonable degree of variation in the sampling rules leads to similar estimates in both countries. I find no evidence for non‐linearities along the fathers' earnings distribution. In contrast, the analysis shows that mobility is higher for the sons at the lowest quartile of the sons' earnings distribution in both countries. In Germany this result is mainly driven by a high downward mobility of sons with fathers in the upper middle part of the earnings distribution. The corresponding pattern is clearly less pronounced in the U.S.     

Pragmatism,Instrumental Value Theory and Social Economics

In an effort to restore trust in the banking sector, the Advisory Committee on the Future of Banks in the Netherlands made a recommendation, which has since been adopted, that bank executives be required to swear an oath akin to the physician's Hippocratic Oath. This examination of the prospects of the Dutch banker's oath addresses two broad issues. One issue is the efficacy of oaths themselves as instruments for achieving the desired end. A second issue concerns the extent to which this particular oath is a useful guide to ethical banking practice. One conclusion of this study is that it would be difficult for any oath in banking to serve a role that is analogous to the Hippocratic Oath in medicine because of the many dissimilarities involved, most notably the lack in banking of a singular focus on service. Second, the Dutch oath, while admirable in its lofty exhortations, fails to provide a reliable guide through the many difficult judgments that must be made in banking.     

A bibliometric study of financial risk literature: a historic approach

This study probes into the development of financial risk literatures through the perspective of bibliometrics. The research samples were collected from the relevant international financial business bibliographic databases. A total of 2727 entries in a span of 29 years from 1970 to 2009 were collected and the results are summarized as follows: (1) the financial risk literatures under influence of the financial turmoil in Asia achieved substantial growth from 1997 to 1998 and an exponential growth curve during the global financial turmoil from 2007 to 2009; (2) the literatures were mainly journals and articles written in English; (3) the United States ranked first in sector productivity; (4) the author productivity of the financial risks was consistent with the Lotka's Law and (5) the document types of the financial risk literatures were mostly dissertation papers on economics and business.