Biometrics
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This article discusses extensions of generalized linear models for the analysis of longitudinal data. Two approaches are considered: subject-specific (SS) models in which heterogeneity in regression parameters is explicitly modelled; and population-averaged (PA) models in which the aggregate response for the population is the focus. ⋯ When the subject-specific parameters are assumed to follow a Gaussian distribution, simple relationships between the PA and SS parameters are available. The methods are illustrated with an analysis of data on mother's smoking and children's respiratory disease.
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Survival from cancer over a certain time period is often measured by the 'relative survival rate'. This is the ratio of the observed survival rate in the group of patients to the survival rate expected in a group of people in the general population, who are similar to the patients with respect to all of the possible factors affecting survival at the beginning of the period, except for the disease under study. ⋯ A method based on the concept of an 'expected life table' is proposed for removal of the bias. Examples based on material from the Finnish Cancer Registry suggest that the practical performance of the proposed method is better than that of other alternatives, even when the relative survival rates in the subgroups are not equal.
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Review Biography Historical Article
The contributions of Jerome Cornfield to the theory of statistics.
This paper is a review of the contributions of Jerome Cornfield to the theory of statistics. It discusses several highlights of his theoretical work as well as describing his philosophy relating theory to application. The three areas discussed are: linear programming, urn sampling and its generalizations to the analysis of variance, and Bayesian inference. ⋯ A brief survey is made of his main contributions to this area. A particularly noteworthy result was his demonstration that for the two-sample slippage problem of location, the likelihood function under a permutation setting is uninformative for the slippage parameter. However, the posterior distribution differs from the prior distribution despite the fact that the likelihood is uninformative.
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Comparative Study
Monotonic dichotomous regression estimates: a burn care example.
Methods for estimating a dichotomous response regression function are discussed. A smoothed nonparametric monotonic estimator is developed and a procedure for estimating its variance is given. In an institutional differences study, the probability of death from a burn injury is related to the severity of the burn injury for patients treated at several specialized burn care units.
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Review Clinical Trial
Adaptive treatment assignment methods and clinical trials.
This paper provides a general review of adaptive experimental designs which utilize accumulating information for assigning the best treatment to the most patients in clinical trials. The historical development of such methods is traced. ⋯ It is asserted that most published methods have important deficiencies that render them unsuitable for application. Suggestions are offered for reorienting this area of research into directions that are potentially more useful for clinical trials.