Model-based control charts in phase 1 statistical process control

In this paper, a general method of constructing control charts for preliminary analysis of individual observations is presented, which is based on recursive score residuals. A simulation study shows that certain implementations of these charts are highly effective in detecting assignable causes.     

Introducing Time‐to‐Educate in a Job‐Search Model

Transition patterns from school to work differ considerably across OECD countries. Some countries exhibit high youth unemployment rates, which can be considered an indicator of the difficulty facing young people trying to integrate into the labour market. At the same time, education is a time‐consuming process, and enrolment and dropout decisions depend on expected duration of studies as well as on job prospects with and without completed degrees. One way to model entry into the labour market is by means of job‐search models, where the job arrival hazard is a key parameter in capturing the ease or difficulty in finding a job. Standard models of job search and education assume that skills can be upgraded instantaneously (and mostly in the form of on‐the‐job training) at a fixed cost. This paper models education as a time‐consuming process, a concept which we call time‐to‐educate, during which an individual faces the trade‐off between continuing education and taking up a job.     

Making sense of corporate social responsibility in international business: experiences from Shell

International business organizations are regularly addressed on their corporate social responsibility (CSR). As illustrated in this paper, it is not yet clear exactly what CSR means to organizations and how to deal with it. In this paper, the authors explore how a sensemaking approach helps to understand the business challenges of CSR within an organizational context. The theories of Karl Weick are applied to the experiences of CSR in Royal Dutch Shell. The authors argue that the key to CSR in international business organizations is to engage stakeholders and start a process of joint sensemaking. Three main competencies are crucial in this: the competency to engage stakeholders through listening and understanding; the creation of an organizational language so that CSR makes sense to members of the organization; and recognizing the momentum of taking action.     

Implementing reverse e-auctions: A learning process

Reverse e-auctions, which enable suppliers to compete on-line in real-time, are changing the way organizations select their suppliers. We explore how five large firms in different industries learned to use e-auctions, and how e-auctions were integrated into their purchasing processes. To successfully implement e-auctions, organizations should: (1) build e-auction competencies; (2) organize for knowledge management; (3) create a holistic sourcing process; (4) focus on the total cost of ownership; and (5) experiment with e-auction designs. Key observations are drawn from the case studies, and implications for supply managers are presented.     

An investigation of transformation-based prediction interval for the Weibull median life

Statistical inference based on the Weibull distribution, a distribution widely used in reliability and survival analysis, is usually difficult as it often involves numerical computation and approximation. However, this distribution can be transformed to near-normality by a simple power transformation. Based on this transformation, a prediction interval (PI) for its median can be easily constructed through an inverse transformation. The procedure for selecting the best power transformation through minimizing Kullback-Leibler information is described. The property of this transformation-based PI is investigated. Simple correction factors are also proposed. It is shown that the transformation-based PI with corrections performs well, irrespective of the sample size and parameter values. Simulation results show that the new PI generally outperforms the existing PI. Numerical examples are given for illustration.     

More thinking on research methods for the resource‐based perspective

We re‐examine the benefits of using a broader set of research methods to address key questions associated with the resource‐based view (RBV) of the firm. In responding to Levitas and Chi, we consider how research inside organizations can complement and augment research relying on secondary data. Copyright © 2002 John Wiley & Sons, Ltd.     

Improved estimation of portfolio value‐at‐risk under copula models with mixed marginals

Portfolio value‐at‐risk (PVAR) is widely used in practice, but recent criticisms have focused on risks arising from biased PVAR estimates due to model specification errors and other problems. The PVAR estimation method proposed in this article combines generalized Pareto distribution tails with the empirical density function to model the marginal distributions for each asset in the portfolio, and a copula model is used to form a joint distribution from the fitted marginals. The copula–mixed distribution (CMX) approach converges in probability to the true marginal return distribution but is based on weaker assumptions that may be appropriate for the returns data found in practice. CMX is used to estimate the joint distribution of log returns for the Taiwan Stock Exchange (TSE) index and the associated futures contracts on SGX and TAIFEX. The PVAR estimates for various hedge portfolios are computed from the fitted CMX model, and backtesting diagnostics indicate that CMX outperforms the alternative PVAR estimators. © 2006 Wiley Periodicals, Inc. Jrl Fut Mark 26:997–1018, 2006     

Finance as a Barrier to Entry: Bank Competition and Industry Structure in Local U.S. Markets

This paper tests how competition in local U.S. banking markets affects the market structure of nonfinancial sectors. Theory offers competing hypotheses about how competition ought to influence firm entry and access to bank credit by mature firms. The empirical evidence, however, strongly supports the idea that in markets with concentrated banking, potential entrants face greater difficulty gaining access to credit than in markets in which banking is more competitive.