A Paradox for the “Smooth Ambiguity” Model of Preference

Two Ellsberg‐style thought experiments are described that reflect on the smooth ambiguity decision model developed by Klibanoff, Marinacci, and Mukerji (2005). The first experiment poses difficulties for the model's axiomatic foundations and, as a result, also for its interpretation, particularly for the claim that the model achieves a separation between ambiguity and the attitude toward ambiguity. Given the problematic nature of its foundations, the behavioral content of the model and how it differs from multiple priors, for example, are not clear. The second thought experiment casts some light on these questions.     

A Bayesian approach to statistical inference in stochastic DEA

Stochastic DEA can deal effectively with noise in the non-parametric measurement of efficiency but unfortunately formal statistical inference on efficiency measures in not possible. In this paper, we provide a Bayesian approach to the problem organized around simulation techniques that allow for finite-sample inferences on efficiency scores. The new methods are applied to efficiency analysis of the Greek banking system for the period 1993–1999. The results show that the majority of the Greek banks operate close to best market practices.     

A generalized Fleming and Harrington's class of tests for interval‐censored data

The class $G^{\rho,\lambda }$ of weighted log‐rank tests proposed by Fleming & Harrington [Fleming & Harrington (1991) Counting Processes and Survival Analysis, Wiley, New York] has been widely used in survival analysis and is nowadays, unquestionably, the established method to compare, nonparametrically, k different survival functions based on right‐censored survival data. This paper extends the $G^{\rho,\lambda }$ class to interval‐censored data. First we introduce a new general class of rank based tests, then we show the analogy to the above proposal of Fleming & Harrington. The asymptotic behaviour of the proposed tests is derived using an observed Fisher information approach and a permutation approach. Aiming to make this family of tests interpretable and useful for practitioners, we explain how to interpret different choices of weights and we apply it to data from a cohort of intravenous drug users at risk for HIV infection. The Canadian Journal of Statistics 40: 501–516; 2012 © 2012 Statistical Society of Canada     

Gender dysphoric/gender variant (GD/GV) children and adolescents: summarizing what we know and what we have yet to learn

The optimal approach to treating minors with gender dysphoria/gender variance (GD/GV) is much more controversial than treating these phenomena in adults. This is because children have limited capacity to participate in decision making regarding their own treatment, and even adolescents have no legal ability to provide informed consent. Minors must, therefore, depend on parents or other caregivers to make treatment decisions on their behalf, including those that will influence the course of their lives in the long term. Presently, the highest level of evidence available for selecting among the various approaches to treatment is best characterized as "expert opinion." Yet, opinions vary widely among experts and are influenced by theoretical orientation and assumptions and beliefs regarding the origins of gender identity, as well as its perceived malleability at particular stages of development. This article outlines some of the more salient points raised by the clinicians who treat GD/GV and their discussants. This article summarizes what the editors believe is known and what has yet to be learned about minors with GD/GV, their families, their treatment, and their surrounding cultures.     

High Sex Ratios at Birth in the Caucasus: Modern Technology to Satisfy Old Desires

During the 1990s, the sex ratio at birth increased considerably and simultaneously in the three independent Caucasian countries, Armenia, Azerbaijan, and Georgia. At the end of the first decade of the twenty‐first century, levels remain abnormally high in Armenia and Azerbaijan (above 114 male births per 100 female births) and show erratic trends in Georgia. Analyzing data from demographic surveys carried out around 2005, we confirm the persistence of high sex ratios in these three countries and document significant differences in fertility intentions and behavior according to the sex of the previous child or children that constitute evidence of the practice of sex‐selective abortion. These countries combine societal features and medical systems that make this phenomenon possible: son preference in a context of low fertility and the possibility of prenatal sex selection given easy access to ultrasound screening and induced abortion. Why high sex ratios are observed only in these three countries of the sub‐region remains, however, an open question.     

Urban growth in China: past, prospect, and its impacts

Rapid growth and globalization of the domestic economy have dramatically accelerated urbanization in China, resulting in significant environmental impacts and challenges for sustainable development. Using a multistate model accounting for distributional aspects of age, sex, education, and migration in rural and urban regions, we estimate the magnitude of urbanization in China through 2030 and examine some major associated sustainability issues. Results indicate that: (1) for a range of assumptions, China’s urban population will nearly double from 2000 to 2030; (2) the labor force will constitute a larger share of total population in urban areas than rural due to internal migration of younger workers—this appears particularly true for the mega-urban metropolises of Beijing and Shanghai; (3) rural populations will experience more aging than urban; and (4) level of education among China’s rural labor force will remain low, which could pressure China’s industrial structural transition from an agricultural to a service-based economy.     

A queuing-theory-based approach to evaluate the efficiency of a network of automated stations and of a communication system

The Regional Meteorological Service for the Emilia-Romagna Region manages a network of automatic weather stations equipped with electronic sensors suitable for measuring meteorological parameters. The automatic stations consist of electronic instruments, which are subject to failures at more or less frequent intervals. A summary of their performance is necessary. In this paper, we compare the results of the summary, such as the contiguous absence or simultaneous inactivity of different stations, with theoretical simulations in order to evaluate the nature and recurrence of the failures. A single- and multi-server queue simulation model was also used to evaluate the performance of the data transmission system, so as to optimize the communications system.