Bayesian prediction for progressively censored data from the Burr model

Received: August 14, 2000; revised version: April 23, 2001     

Choice of Parametric Accelerated Life and Proportional Hazards Models for Survival Data: Asymptotic Results

We discuss the impact of misspecifying fully parametric proportional hazards and accelerated life models. For the uncensored case, misspecified accelerated life models give asymptotically unbiased estimates of covariate effect, but the shape and scale parameters depend on the misspecification. The covariate, shape and scale parameters differ in the censored case. Parametric proportional hazards models do not have a sound justification for general use: estimates from misspecified models can be very biased, and misleading results for the shape of the hazard function can arise. Misspecified survival functions are more biased at the extremes than the centre. Asymptotic and first order results are compared. If a model is misspecified, the size of Wald tests will be underestimated. Use of the sandwich estimator of standard error gives tests of the correct size, but misspecification leads to a loss of power. Accelerated life models are more robust to misspecification because of their log-linear form. In preliminary data analysis, practitioners should investigate proportional hazards and accelerated life models; software is readily available for several such models.     

Bayesian modelling of catch in a north-west Atlantic fishery

Summary. We model daily catches of fishing boats in the Grand Bank fishing grounds. We use data on catches per species for a number of vessels collected by the European Union in the context of the Northwest Atlantic Fisheries Organization. Many variables can be thought to influence the amount caught: a number of ship characteristics (such as the size of the ship, the fishing technique used and the mesh size of the nets) are obvious candidates, but one can also consider the season or the actual location of the catch. Our database leads to 28 possible regressors (arising from six continuous variables and four categorical variables, whose 22 levels are treated separately), resulting in a set of 177 million possible linear regression models for the log-catch. Zero observations are modelled separately through a probit model. Inference is based on Bayesian model averaging, using a Markov chain Monte Carlo approach. Particular attention is paid to the prediction of catches for single and aggregated ships.     

Economics, law, and covenant marriage

Covenant marriage may be difficult to understand as a gender issue. However, marriage and divorce are closely linked to workforce participation and child rearing. This piece looks at new proposals for choices in divorce regime from legal, economic, and social perspectives, concluding that the option of contracting a more permanent form of marriage increases the possibilities for women and signals societal interest in promoting more stable families. The article favorably compares Louisiana covenant marriage legislation to other states' suggestions for returns to fault-only regimes, and pays some attention to the role one state's marriage and divorce laws play in the federal system.     

Outsourcing to emerging markets: Theoretical perspectives and policy implications

Creating value through outsourcing has emerged as a popular competitive strategy for firms in various industries. In order to survive in the domestic and international marketplaces, firms, especially in developed countries, are seeking opportunities offshore, which is one focus of globalization. Offshore outsourcing has emerged as a popular competitive strategy and emerging markets have become increasingly attractive locations. As firms in developed countries (e.g., the US) continue to face enormous challenges to sustain competitive advantage, outsourcing to emerging markets is becoming an increasingly important source of business renewal and corporate transformation.In spite of the growing strategic significance of sourcing, we have limited knowledge of offshoring and outsourcing to emerging markets. The objectives of this review are fourfold: (1) to provide a better understanding of the concepts of offshoring and outsourcing business models, (2) to discuss relevant theoretical perspectives related to outsourcing, (3) to present a taxonomy of outsourcing strategies drawing on the extant literature, and (4) to discuss public policy implications. Conclusions and direction for future research are provided.     

A study of DEA models without explicit inputs

In performance evaluations, data without explicit inputs (such as index data, pure output data) are widely used. To directly use such data, this paper presents a study on building DEA models without explicit inputs, so-called DEA-WEI models, which are applicable to the evaluation applications where inputs are not directly considered. We provide an axiom foundation of these kinds of models, and further discuss how to incorporate value judgments of decision makers into these DEA-WEI models. Several such models are derived. Finally, applications of the DEA-WEI models are presented.     

The Emergency of Climate Change: Why Are We Failing to Take Action?

Latane and Darley developed a five-stage model to understand why people do and do not help other people in emergency situations. We extend their five-stage model to explore why people do and do not take action against climate change. We identify the factors that make climate change difficult to notice and ambiguous as an emergency; we explore barriers to taking responsibility for action; and we discuss the issues of efficacy and costs versus benefits that make action unlikely. The resulting analysis is useful on two levels. For educators and policy makers, the model suggests the most efficacious approaches to galvanizing action among U.S. citizens. For social scientists, the model provides a valuable framework for integrating research from diverse areas of psychology and suggests fruitful avenues for future empirical research.     

Objectivism and Bias on the Study of the Israeli–Palestinian Conflict

The author responds to reviews of his book, Planting Hatred, Sowing Pain: The Psychology of the Israeli-Palestinian Conflict. Reviewers argue that you cannot understand the psychology of this conflict from an objective perspective, without taking issues such as historical context and social justice in consideration. The author argues that this detachment is necessary in order to find a solution, since we need to move beyond an orientation to the past that amounts to a culpability paradigm, and into an orientation to the future and a resolution paradigm. Only after you achieve peace and build mutual trust, could the parties be ready to do soul searching and take responsibility for their past actions.     

THE EFFECTS OF UNCERTAINTY ON THE LEVERAGE OF NONFINANCIAL FIRMS

This paper investigates the link between the optimal level of nonfinancial firms' short-term leverage and macroeconomic and idiosyncratic sources of uncertainty. We develop a structural model of a firm's value maximization problem that predicts a negative relationship between uncertainty and optimal levels of borrowing. This proposition is tested using a panel of nonfinancial U.S. firms drawn from the COMPUSTAT quarterly database covering the period 1993–2003. The estimates confirm that as either form of uncertainty increases, firms decrease their levels of short-term leverage. This effect is stronger for macroeconomic uncertainty than for idiosyncratic uncertainty. ( JEL C23, D8, D92, G32)