Evolutionary dynamics on infinite strategy spaces

Summary. The study of evolutionary dynamics was so far mainly restricted to finite strategy spaces. In this paper we show that this unsatisfying restriction is unnecessary. We specify a simple condition under which the continuous time replicator dynamics are well defined for the case of infinite strategy spaces. Furthermore, we provide new conditions for the stability of rest points and show that even strict equilibria may be unstable. Finally, we apply this general theory to a number of applications like the Nash demand game, the War of Attrition, linear-quadratic games, the harvest preemption game, and games with mixed strategies. Received: June 25, 1999; revised version: January 31, 2000     

Performance hypothesis testing with the Sharpe ratio: The case of hedge funds

As recent research highlights that the Sharpe ratio has a decision theoretic foundation even in the case of asymmetric or fat-tailed excess returns and thus is adequate even for the evaluation of hedge funds, this note provides the first Sharpe ratio based performance analysis of the hedge fund market. Furthermore, it addresses the important practical question whether the choice of hypothesis test used to statistically compare Sharpe ratios can influence an investor’s hedge fund selection process. Our key findings are as follows: (i) Only a small fraction of hedge funds in our large dataset can significantly outperform passive investments in corresponding hedge fund indices. (ii) Especially in the presence of autocorrelated or skewed excess returns, the traditional test of Jobson and Korkie, 1981, Memmel, 2003 tends to overstate the number of significant outperformers and thus provides potentially misleading information for investors. Decision makers are advised to use the bootstrap test of Ledoit and Wolf (2008) allowing robust and more reliable inference.     

IMPORTATION AND INNOVATION

Importation of drugs into the US may soon become legal. Since prices of drugs are lower in most other countries than they are in the US, importation would result in a decline in US drug prices. The purpose of this paper is to assess the consequences of importation for new drug development. First, the author presents a simple theoretical model of drug development which suggests that the elasticity of innovation with respect to the expected price of drugs should be at least as great as the elasticity of innovation with respect to expected market size (disease incidence). Then, the cross-sectional relationship between pharmaceutical innovation and market size among a set of diseases (different types of cancer) exhibiting substantial exogenous variation in expected market size is examined. Two different measures of pharmaceutical innovation are analysed: the number of distinct chemotherapy regimens for treating a cancer site and the number of articles published in scientific journals pertaining to drug therapy for that cancer site. Both analyses indicate that the amount of pharmaceutical innovation increases with disease incidence. The elasticity of the number of chemotherapy regimens with respect to the number of cases is 0.53. The elasticity of MEDLINE drug cites with respect to cancer incidence throughout the world is 0.60. In the long run, a 10% decline in drug prices would therefore be likely to cause at least a 5–6% decline in pharmaceutical innovation. Evidence suggests that pharmaceutical industry employment would also decline (by at least 3.5–4%) in response to an exogenous 10% decline in drug prices.     

An Epistemic Analysis of (Un)Sustainable Business

Michel Foucault famously analysed orders of knowledge, ‘epistemes’, in past European ages. In this study, his analytical method is fruitfully applied to gaining a better understanding of business sustainability within and beyond the Modern episteme. After an introduction to the contextual background for the study, this article provides (i) a justification for the use of a Foucauldian epistemic analytical method, (ii) an outline of the method, (iii) an application of the method to identify four sets of questions (morality, specialisation, anthropologization and mathematicization) that are both direct derivatives of the Modern episteme and problematic for sustainable development, and finally (iv) an application of the method to consider evidence for the emergence of a new episteme. Conclusions are also provided.     

A rejoinder to the commentaries on Professor Chambers' 1999 paper the poverty of accounting discourse

The resource presented in this paper introduces and contextualises the teaching of Customer Lifetime Valuation (CLV) to management accounting students. CLV is a relatively recent innovation. It involves calculating the present value of expected net cash flows generated over the lifetime of an organisation's relationship with a particular customer/customer segment and using this information better to manage returns derived from a customer base. The Teaching Resource provides an introduction to the topic, suggested learning objectives, suitable student reading, and an innovative case (OzInsure case) facilitating students' technical competence and evaluation of CLV. Also included are suggested solutions and further background information situating the use and development of the teaching resource. Feedback received from peers and students indicates the utility of the Teaching Resource, and provides guidance as to its future development. More generally, this resource illustrates the feasibility of using instructors' research experiences to inform learning in management accounting.     

An Empirical Comparison of the Four Channel Flow Model and Adventure Experience Paradigm

The objective of this study was to conduct empirical comparisons between two models of optimal experience within an on-site whitewater kayaking setting using a modification of the Experience Sampling Method. Four concerns are examined: (1) differences in explanatory power between the four channel flow model and the Adventure Experience Paradigm, (2) convergent validity among measures used to determine conditions within these models, (3) differences among measures of perceived challenge and risk between test times of Class I-V river difficulty, and (4) differences among measures of perceived skill and competence between test times of Class I-V river difficulty. Questionnaires were administered in the Cheat River Canyon in West Virginia to 52 whitewater kayakers at eight sites of various levels of river difficulty. Data were analyzed at the experience level, rather than between subjects, using 409 experience sampling observations. Hypothesis testing, performed with statistical analyses (stepwise regression, correlations, and repeated measures ANOVA), suggested that the explanatory powers of the four channel flow model and Adventure Experience Paradigm were similar and indicated support for convergent and ecological validity of measures used to determine conditions within each of the two models.     

How Environmental Management Competitive Pressure Affects a Focal Firm's Environmental Innovation Activities: A Green Supply Chain Perspective

Recently, environmental management offers firms a source of competitive advantage in the marketplace. The development of environmental innovations is critical to the success of today's firms. Drawing on the Schumpeterian perspective of competition, this research examines how the perception of rival firms' green success influences a firm to pursue and produce environmental innovation through its green supply chain integration activities. Using survey data from 230 firms, a conceptual model is developed and tested using structural equation modeling. We find that the firms in our sample do perceive pressure from their competitors' success in environmental management activities, and thus take supply chain action to pursue integration activities. By differentiating incremental and radical environmental innovation, this study also reveals the role of three dimensions of green supply chain integration (internal, supplier, and customer integration of green product development) on incremental and radical environmental innovation separately. Specifically, findings suggest that green supply chain integration has a positive impact on developing incremental environmental innovation, while only customer integration has a significant positive impact on developing radical environmental innovation.