Relative risk aversion, relative prudence and comparative statics under uncertainty: The case of (μ, σ)‐preferences

From the expected‐utility approach, relative risk aversion being smaller than one and relative prudence being smaller than two emerge as preference restrictions that fully determine the optimal responses of decisions under uncertainty to certain shifts in probability distributions. We characterize the magnitudes of relative risk aversion and relative prudence in terms of the two‐parameter, mean‐standard deviation approach. We demonstrate that this characterization is instrumental in obtaining comparative static results in the two‐parameter setting. We further relate our findings to the results in the expected‐utility framework.     

Rent, risk, and replication: Preference adaptation in winner-take-all markets

We study the evolution of an economy where agents who are heterogeneous with respect to risk attitudes can either earn a certain income or enter a risky rent-seeking contest. We assume that agents behave rationally given their preferences, but that the population distribution of preferences evolves over time in response to material payoffs. We show that, in particular, initial distributions with full support converge to stationary states where all types are still present. Although rents are perfectly dissipated in material terms at a steady state, efficiency is greater than if everybody had been risk neutral, since risk lovers specialize in rent seeking.     

Altruism, equity, and reciprocity in a gift-exchange experiment: an encompassing approach

Considerable experimental evidence suggests that non-pecuniary motives must be addressed when modeling behavior in economic contexts. Recent theories of non-pecuniary motives can be classified as altruism-, equity-, or reciprocity-based. We outline the qualitative differences in prediction these alternative explanations yield in a gift-exchange game. We estimate and compare leading approaches in these categories, using experimental data. We then offer a flexible approach that nests the above three approaches, thereby allowing for nested hypothesis testing and for determining the relative strength of each of the competing theories. In addition, the encompassing approach provides a functional form for utility in different settings without the restrictive nature of the approaches nested within it. Using this flexible form for nested tests, we find that intentional reciprocity, distributive concerns, and altruistic considerations all play a significant role in players' decisions.     

Decomposition of Fraud‐Risk Assessments and Auditors' Sensitivity to Fraud Cues*

Practitioners and regulators are concerned that when auditors perceive management's attitude or character as indicative of low fraud risk, they are not sufficiently sensitive to high levels of incentive or opportunity risks in their overall fraud‐risk assessments. In this study, we examine whether a fraud‐triangle decomposition of fraud‐risk assessments (that is, separately assessing attitude, opportunity, and incentive risks prior to assessing overall fraud risk) increases auditors' sensitivity to opportunity and incentive cues when perceptions of management's attitude suggest low fraud risk. In an experiment with 52 practicing audit managers, we find that auditors who decompose fraud‐risk assessments are more sensitive to opportunity and incentive cues when making their overall assessments than auditors who simply make an overall fraud‐risk assessment. However, this increased sensitivity to opportunity and incentive cues appears to happen only when those cues suggest low fraud risk. When opportunity and incentive cues suggest high fraud risk, auditors are equally sensitive to those cues whether they use a decomposition or a holistic approach. We discuss and examine potential explanations for this finding.     

Game-theoretic properties of Final-Offer Arbitration

Final-Offer Arbitration (FOA) is a dispute settlement procedure in which an arbitrator chooses one side's final position as the resolution. Game-theoretic models of FOA in two-sided interest disputes are reviewed, especially models of the disputants' final offer choices under uncertainty about the arbitrator's preferences. The extent to which the Brams-Merrill Theorem (1986) reveals optimal strategic behavior under FOA, and the implications for efficiency and equity, are assessed. Analysis of a model not satisfying the hypotheses of the Theorem suggests that, for some arbitrators, FOA can have an undesirable tendency. Another game model is used to address the question of how disputants' differential risk-aversion is reflected in their strategic behavior, and in the fairness of FOA outcomes. This calculation clarifies some apparently contradictory empirical evidence about FOA.     

In-hospital risk of venous thromboembolism and bleeding and associated costs for patients undergoing total hip or knee arthroplasty

Abstract

Objective:

Benefits of anti-coagulation for venous thromboembolism (VTE) prevention in total hip and knee arthroplasty (THA/TKA) may be offset by increased risk of bleeding. The aim was to assess in-hospital risk of VTE and bleeding after THA/TKA and quantify any increased costs.

Methods:

Healthcare claims from the Premier Perspective^TM Comparative Hospital Database (January 2000–September 2008) were selected for subjects ≥18 years with ≥1 diagnosis code for THA/TKA. VTE was defined as ≥1 code for deep vein thrombosis or pulmonary embolism. Bleeding was classified as major/non-major. Incremental in-hospital costs associated with VTE and bleeding were calculated as cost differences between inpatients with VTE or bleeding matched 1:1 with inpatients without VTE or bleeding.

Results:

A total of 820,197 inpatient stays were identified: 8042 had a VTE event and 7401 a bleeding event (2740 major bleeding). The risks of VTE, any bleeding, and major bleeding were 0.98, 0.90, and 0.33/100 inpatient stays, respectively. Mean incremental in-hospital costs per inpatient were $2663 for VTE, $2028 for bleeding, and $3198 for major bleeding.

Limitations:

These included possible inaccuracies or omissions in procedures, diagnoses, or costs of claims data; no information on the amount of blood transfused or decreases in the hemoglobin level to evaluate bleeding event severity; and potential biases due to the observational design of the study.

Conclusions:

In-hospital risk and incremental all-cause costs with THA/TKA were higher for VTE than for bleeding. Despite higher costs, major bleeding occurred less frequently than VTE, suggesting a favorable benefit/risk profile for VTE prophylaxis in THA/TKA.     

Intraday Value at Risk (IVaR) using tick-by-tick data with application to the Toronto Stock Exchange

This paper investigates the use of tick-by-tick data for intraday market risk measurement. We propose a method to compute an Intraday Value at Risk based on irregularly spaced high-frequency data and an intraday Monte Carlo simulation. A log-ACD–ARMA–EGARCH model is used to specify the joint density of the marked point process of durations and high-frequency returns. We apply our methodology to transaction data for three stocks actively traded on the Toronto Stock Exchange. Compared to traditional techniques applied to intraday data, our methodology has two main advantages. First, our risk measure has a higher informational content as it takes into account all observations. On the total risk measure, our method allows for distinguishing the effect of random trade durations from the effect of random returns, and for analyzing the interaction between these factors. Thus, we find that the information contained in the time between transactions is relevant to risk analysis, which is consistent with predictions from asymmetric-information models in the market microstructure literature. Second, once the model has been estimated, the IVaR can be computed by any trader for any time horizon based on the same information and with no need of sampling the data and estimating the model again when the horizon changes. Backtesting results show that our approach constitutes reliable means of measuring intraday risk for traders who are very active in the market.     

中美科技银行比较研究

从发展演变、外部环境、运营机制等方面对中美科技银行进行了系统比较,为我国科技银行的发展提供了有益的启示。研究结果表明：①发达的高技术产业、创业投资市场和宽松的监管环境为美国科技银行的发展创造了一个有利的外部环境。我国在这些方面的滞后或不足,是制约科技银行发展的主要因素;②美国科技银行在商业模式、风险控制机制等方面已经发展得非常成熟,为美国高技术产业的发展提供了重要支撑。我国科技银行则处于不断探索的阶段,还没找到一条适合自己发展的道路。最后,从营造良好外部环境和优化内部运营机制的角度,提出了发展中国科技银行的相关建议。     

信用风险水平与宏观经济变量的实证研究——基于中国、美国、日本部分银行的比较分析

基于1999～2007年中国、美国和日本部分银行的不良贷款率数据,本文对影响银行信用风险的宏观经济因素进行了实证研究和比较分析。结果表明:(1)中国的银行信用风险水平与失业率呈现显著的负相关关系;(2)表面上美国的银行信用风险水平极低,而且不受宏观经济变量波动的影响,但是实际上其风险被金融衍生工具隐藏并积累起来;(3)日本的银行信用风险水平与CPI呈现显著的负相关关系。最后本文提出了几点建议。