New ASA Fellows — 1964

This is an invited expository article for The American Statistician. It reviews the nonparametric estimation of statistical error, mainly the bias and standard error of an estimator, or the error rate of a prediction rule. The presentation is written at a relaxed mathematical level, omitting most proofs, regularity conditions, and technical details.     

美国劳动法的放松规制

经过艰难的谈判历程 ,中国政府终于在 2 0 0 1年底加入WTO。政治学对政府职能定位、政府与市场关系的关注也已悄然转向规制分析领域。为了提高政府绩效、提升公共利益、制定完善的公共政策 ,放松规制和重建规制的论题已成为学术界、政府职能部门研究的热点之一。本期安排几篇有关政府规制问题研究的论文 ,旨在引发学术界对这一问题进行深入探讨。     

Bayesian fractional polynomials

This paper sets out to implement the Bayesian paradigm for fractional polynomial models under the assumption of normally distributed error terms. Fractional polynomials widen the class of ordinary polynomials and offer an additive and transportable modelling approach. The methodology is based on a Bayesian linear model with a quasi-default hyper-g prior and combines variable selection with parametric modelling of additive effects. A Markov chain Monte Carlo algorithm for the exploration of the model space is presented. This theoretically well-founded stochastic search constitutes a substantial improvement to ad hoc stepwise procedures for the fitting of fractional polynomial models. The method is applied to a data set on the relationship between ozone levels and meteorological parameters, previously analysed in the literature.     

NONLINEAR TUBE-FITTING FOR THE ANALYSIS OF ANATOMICAL AND FUNCTIONAL STRUCTURES

We are concerned with the estimation of the exterior surface and interior summaries of tube-shaped anatomical structures. This interest is motivated by two distinct scientific goals, one dealing with the distribution of HIV microbicide in the colon and the other with measuring degradation in white-matter tracts in the brain. Our problem is posed as the estimation of the support of a distribution in three dimensions from a sample from that distribution, possibly measured with error. We propose a novel tube-fitting algorithm to construct such estimators. Further, we conduct a simulation study to aid in the choice of a key parameter of the algorithm, and we test our algorithm with validation study tailored to the motivating data sets. Finally, we apply the tube-fitting algorithm to a colon image produced by single photon emission computed tomography (SPECT) and to a white-matter tract image produced using diffusion tensor imaging (DTI).     

The maximum likelihood estimators in the growth curve model with serial covariance structure

The maximum likelihood estimators of unknown parameters in the growth curve model with serial covariance structure under some conditions are derived in the paper.     

A Flexible Approach to Time-varying Coefficients in the Cox Regression Setting

Research on methods for studying time-to-event data (survival analysis) has been extensive in recent years. The basic model in use today represents the hazard function for an individual through a proportional hazards model (Cox, 1972). Typically, it is assumed that a covariate's effect on the hazard function is constant throughout the course of the study. In this paper we propose a method to allow for possible deviations from the standard Cox model, by allowing the effect of a covariate to vary over time. This method is based on a dynamic linear model. We present our method in terms of a Bayesian hierarchical model. We fit the model to the data using Markov chain Monte Carlo methods. Finally, we illustrate the approach with several examples. This revised version was published online in July 2006 with corrections to the Cover Date.     

Social process theory of emotion: A dynamic systems approach

In this paper we apply a dynamic systems perspective to infant emotional development. We propose that emotions are not states but self-organizing dynamic processes intimately tied to the flow of an individual's activity in a context. We review data on the relationship between emotional actions and the social context, in particular the development of smiling and laughter. These data are more adequately explained by our perspective than by other theories of emotional development. We provide a model for how emotional processes in early infancy become embedded into sociocultural systems, and suggest new avenues of research on emotional development.     

Statistical analysis for negotiation support

In this paper we provide an overview of the issues involved in using statistical analysis to support the process of international negotiation. We will illustrate how the approach can contribute to a negotiator's understanding and control of the interactions that occur during the course of a negotiation. The techniques are suited to the analysis of data collected from ongoing discussions and moves made by the parties. The analyses are used to illuminate influences and processes as they operate in particular cases or in negotiations in general. They do not identify a best strategy or outcome from among alternatives suggested either from theoretical assumptions about rationality and information-processing (see Munier and Rullière's paper in this issue), from personal preference structures (see Spector's paper in this issue), or from a rule-based modeling system (see Kersten's paper in this issue). This distinction should be evident in the discussion to follow, organized into several sections: From Empirical to Normative Analysis; Statistical Analysis for Situational Diagnosis; Time-Series Analysis of Cases, and Knowledge as Leverage Over the Negotiation Process. In a final section, we consider the challenge posed by attempts to implement these techniques with practitioners.     

Managed care and traditional insurance: Comparing quality of care

The article compares quality of care under the traditional "fee–for–service" system with that given by "managed care" providers in the United States. Outcomes have been mixed, with most studies reporting on one hand a decline in the propensity of patients of health maintenance organizations (HMOs) to seek treatment and, on the other, lower patient satisfaction. The quality of care has not deteriorated, however, except in the case of that given to vulnerable patients.