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作者：Farewell, D. M.
作者单位：Cardiff University
摘要：We consider solutions to generalized estimating equations with singular working correlation matrices, of which the estimator of Diggle et al. (2007) is a special case. We give explicit conditions for consistent estimation when the pattern of observations may be informative. In such cases, simulations reveal reduced bias and reduced mean squared error compared with existing alternatives. A study of peritoneal dialysis is used to illustrate the methodology.
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作者：Wang, Huixia Judy; Zhou, Xiao-Hua
作者单位：North Carolina State University; US Department of Veterans Affairs; Veterans Health Administration (VHA); Vet Affairs Puget Sound Health Care System
摘要：We propose a new approach for analyzing skewed and heteroscedastic health care cost data through regression of the conditional quantiles of the transformed cost. Using the appealing equivariance property of quantiles to monotone transformations, we propose a distribution-free estimator of the conditional mean cost on the original scale. The proposed method is extended to a two-part heteroscedastic model to account for zero costs commonly seen in health care cost studies. Simulation studies ind...
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作者：Yao, Fang; Mueller, Hans-Georg
作者单位：University of Toronto; University of California System; University of California Davis
摘要：We extend the common linear functional regression model to the case where the dependency of a scalar response on a functional predictor is of polynomial rather than linear nature. Focusing on the quadratic case, we demonstrate the usefulness of the polynomial functional regression model, which encompasses linear functional regression as a special case. Our approach works under mild conditions for the case of densely spaced observations and also can be extended to the important practical situat...
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作者：Hall, Peter; Xue, Jing-Hao
作者单位：University of Melbourne; University of London; University College London
摘要：In standard parametric classifiers, or classifiers based on nonparametric methods but where there is an opportunity for estimating population densities, the prior probabilities of the respective populations play a key role. However, those probabilities are largely ignored in the construction of high-dimensional classifiers, partly because there are no likelihoods to be constructed or Bayes risks to be estimated. Nevertheless, including information about prior probabilities can reduce the overa...
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作者：Abramovich, Felix; Grinshtein, Vadim; Petsa, Athanasia; Sapatinas, Theofanis
作者单位：Tel Aviv University; Open University Israel; University of Cyprus
摘要：We consider the problem of estimating the unknown response function in the Gaussian white noise model. We first utilize the recently developed Bayesian maximum a posteriori testimation procedure of Abramovich et al. (2007) for recovering an unknown high-dimensional Gaussian mean vector. The existing results for its upper error bounds over various sparse l(p)-balls are extended to more general cases. We show that, for a properly chosen prior on the number of nonzero entries of the mean vector, ...
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作者：Agresti, Alan; Ryu, Euijung
作者单位：State University System of Florida; University of Florida; Mayo Clinic
摘要：We propose pseudo-score confidence intervals for parameters in models for discrete data. The confidence interval is obtained by inverting a test that uses a Pearson chi-squared statistic to compare fitted values for the working model with fitted values of the model when a parameter of interest takes various fixed values. For multinomial models, the pseudo-score method simplifies to the score method when the model is saturated and otherwise it is asymptotically equivalent to score and likelihoo...
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作者：Cox, D. R.; Wong, M. Y.
作者单位：University of Oxford; Hong Kong University of Science & Technology
摘要：A simple case of Poisson regression is used to study the potential gain in efficiency from using a mixed model representation. Possible systematic errors arising from misspecification of the random terms in the model are examined. It is shown in particular that for a special but realistic problem, appreciable bias may arise from misspecification of a random component.
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作者：Scheike, Thomas H.; Sun, Yanqing; Zhang, Mei-Jie; Jensen, Tina Kold
作者单位：University of Copenhagen; University of North Carolina; University of North Carolina Charlotte; Medical College of Wisconsin; University of Southern Denmark
摘要：We propose a semiparametric random effects model for multivariate competing risks data when the failures of a particular type are of interest. Under this model, the marginal cumulative incidence functions follow a generalized semiparametric additive model. The associations between the cause-specific failure times can be studied through dependence parameters of copula functions that are allowed to depend on cluster-level covariates. A cross-odds ratio-type measure is proposed to describe the as...
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作者：Wang, Suojin; Qian, Lianfen; Carroll, Raymond J.
作者单位：Texas A&M University System; Texas A&M University College Station; State University System of Florida; Florida Atlantic University
摘要：Efficient estimation of parameters is a major objective in analyzing longitudinal data. We propose two generalized empirical likelihood-based methods that take into consideration within-subject correlations. A nonparametric version of the Wilks theorem for the limiting distributions of the empirical likelihood ratios is derived. It is shown that one of the proposed methods is locally efficient among a class of within-subject variance-covariance matrices. A simulation study is conducted to inve...
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作者：Reid, N.; Fraser, D. A. S.
作者单位：University of Toronto
摘要：Higher-order approximations to p-values can be obtained from the loglikelihood function and a reparameterization that can be viewed as a canonical parameter in an exponential family approximation to the model. This approach clarifies the connection between Skovgaard (1996) and Fraser et al. (1999a), and shows that the Skovgaard approximation can be obtained directly using the mean loglikelihood function.
