An alternative approach to confidence interval estimation for the win ratio statistic.

abstract：:The log-rank test is widely used to compare two survival distributions in a randomized clinical trial, while partial likelihood (Cox, 1975) is the method of choice for making inference about the hazard ratio under the Cox (1972) proportional hazards model. The Wald 95% confidence interval of the hazard ratio may inclu...

journal_title：Biometrics

authors： Lin DY,Dai L,Cheng G,Sailer MO

更新日期：2016-12-01 00:00:00

abstract：:In biomedical cohort studies for assessing the association between an outcome variable and a set of covariates, usually, some covariates can only be measured on a subgroup of study subjects. An important design question is-which subjects to select into the subgroup to increase statistical efficiency. When the outcome ...

journal_title：Biometrics

authors： Wang L,Williams ML,Chen Y,Chen J

更新日期：2020-03-01 00:00:00

abstract：:A method is presented for choosing an additive constant c when transforming data x to y = log(x + c). The method preserves Type I error probability and power in ANOVA under the assumption that the x + c for some c are log-normally distributed. The method has advantages similar to those of rank transformations--namely,...

journal_title：Biometrics

authors： Berry DA

更新日期：1987-06-01 00:00:00

abstract：:Variable selection for recovering sparsity in nonadditive and nonparametric models with high-dimensional variables has been challenging. This problem becomes even more difficult due to complications in modeling unknown interaction terms among high-dimensional variables. There is currently no variable selection method ...

journal_title：Biometrics

authors： Fang Z,Kim I,Schaumont P

更新日期：2016-12-01 00:00:00

abstract：:We study publication bias in meta-analysis by supposing there is a population (y, sigma) of studies which give treatment effect estimates y approximately N(theta, sigma(2)). A selection function describes the probability that each study is selected for review. The overall estimate of theta depends on the studies selec...

journal_title：Biometrics

authors： Henmi M,Copas JB,Eguchi S

更新日期：2007-06-01 00:00:00

abstract：:With advancements in technology, the collection of multiple types of measurements on a common set of subjects is becoming routine in science. Some notable examples include multimodal neuroimaging studies for the simultaneous investigation of brain structure and function and multi-omics studies for combining genetic an...

journal_title：Biometrics

authors： Zhao Y,Li L,Caffo BS

更新日期：2020-08-13 00:00:00

abstract：:The Colton model for the choice between two medical treatments is studied, with the additional assumption that there is a time lag between the administration of the treatments and the availability of the responses. Two simple procedures are suggested for dealing with patients who arrive during the waiting period, caus...

journal_title：Biometrics

authors： Langenberg P,Srinivasan R

更新日期：1981-03-01 00:00:00

abstract：:We derive a likelihood score method for interval estimation of the intraclass version of the kappa coefficient of agreement with binary classification using a general theory of Bartlett (1953, Biometrika 40, 306-317). By exact evaluation, we investigate statistical properties of the score method, the chi-square goodne...

journal_title：Biometrics

authors： Nam JM

更新日期：2000-06-01 00:00:00

abstract：:We consider the problem of estimating a population size from successive catches taken during a removal experiment and propose two estimating functions approaches, the traditional quasi-likelihood (TQL) approach for dependent observations and the conditional quasi-likelihood (CQL) approach using the conditional mean an...

journal_title：Biometrics

authors： Wang YG

更新日期：1999-12-01 00:00:00

abstract：:Statistical methods for the detection of genes influencing quantitative traits with the aid of genetic markers are well developed for normally distributed, fully observed phenotypes. Many experiments are concerned with failure-time phenotypes, which have skewed distributions and which are usually subject to censoring ...

journal_title：Biometrics

authors： Diao G,Lin DY

更新日期：2005-09-01 00:00:00

abstract：:Likelihood ratio tests for parameters estimated assuming normally distributed errors are examined under a variety of homoscedastic and heteroscedastic variance assumptions. It is assumed that gamma ij, the jth observation from the ith population, is distributed as N[mu(chi ij, beta i), (sigma i mu(chi ij, beta i)theta...

journal_title：Biometrics

authors： Kimura DK

更新日期：1990-09-01 00:00:00

abstract：:A critical component of longitudinal study design involves determining the sampling schedule. Criteria for optimal design often focus on accurate estimation of the mean profile, although capturing the between-subject variance of the longitudinal process is also important since variance patterns may be associated with ...

journal_title：Biometrics

authors： Wu M,Diez-Roux A,Raghunathan TE,Sánchez BN

更新日期：2018-03-01 00:00:00

abstract：:This paper considers methods for estimating the relationship between a binary response Y and the genetic effects responsible for a second binary trait Z. The responses Y are observed only for target individuals, and the responses Z are observed only for the relatives of these targets. The analysis consists of two part...

journal_title：Biometrics

authors： Houwing-Duistermaat JJ,van Houwelingen HC,de Winter JP

更新日期：2000-09-01 00:00:00

abstract：:In clinical studies, longitudinal biomarkers are often used to monitor disease progression and failure time. Joint modeling of longitudinal and survival data has certain advantages and has emerged as an effective way to mutually enhance information. Typically, a parametric longitudinal model is assumed to facilitate t...

journal_title：Biometrics

authors： Ding J,Wang JL

更新日期：2008-06-01 00:00:00

abstract：:In a period starting around 2007, the Hand, Foot, and Mouth Disease (HFMD) became wide-spreading in China, and the Chinese public health was seriously threatened. To prevent the outbreak of infectious diseases like HFMD, effective disease surveillance systems would be especially helpful to give signals of disease outb...

journal_title：Biometrics

authors： Zhang J,Kang Y,Yang Y,Qiu P

更新日期：2015-09-01 00:00:00

abstract：:In epidemiologic studies, subjects are often misclassified as to their level of exposure. Ignoring this misclassification error in the analysis introduces bias in the estimates of certain parameters and invalidates many hypothesis tests. For situations in which there is misclassification of exposure in a follow-up stu...

journal_title：Biometrics

authors： Reade-Christopher SJ,Kupper LL

更新日期：1991-06-01 00:00:00

abstract：:Development of HIV resistance mutations is a major cause for failure of antiretroviral treatment. This article proposes a method for jointly modeling the processes of viral genetic changes and treatment failure. Because the viral genome is measured with uncertainty, a hidden Markov model is used to fit the viral genet...

journal_title：Biometrics

authors： Hu C,De Gruttola V

更新日期：2007-03-01 00:00:00

abstract：:A new test using incidence data is developed for testing whether two or more groups have the same seasonal pattern. The method fits sine waves to the data with a fundamental period of one cycle per year, and has the possibility of using higher harmonics, when necessary, to adequately model the data. The seasonal patte...

journal_title：Biometrics

authors： Jones RH,Ford PM,Hamman RF

更新日期：1988-12-01 00:00:00

abstract：:Spatial replication is a common theme in count surveys of animals. Such surveys often generate sparse count data from which it is difficult to estimate population size while formally accounting for detection probability. In this article, I describe a class of models (N-mixture models) which allow for estimation of pop...

journal_title：Biometrics

authors： Royle JA

更新日期：2004-03-01 00:00:00

abstract：:We propose methods for Bayesian inference for a new class of semiparametric survival models with a cure fraction. Specifically, we propose a semiparametric cure rate model with a smoothing parameter that controls the degree of parametricity in the right tail of the survival distribution. We show that such a parameter ...

journal_title：Biometrics

authors： Ibrahim JG,Chen MH,Sinha D

更新日期：2001-06-01 00:00:00

abstract：:There has been great interest in developing nonlinear structural equation models and associated statistical inference procedures, including estimation and model selection methods. In this paper a general semiparametric structural equation model (SSEM) is developed in which the structural equation is composed of nonpar...

journal_title：Biometrics

authors： Guo R,Zhu H,Chow SM,Ibrahim JG

更新日期：2012-06-01 00:00:00

abstract：:This paper considers the impact of bias in the estimation of the association parameters for longitudinal binary responses when there are drop-outs. A number of different estimating equation approaches are considered for the case where drop-out cannot be assumed to be a completely random process. In particular, standar...

journal_title：Biometrics

authors： Fitzmaurice GM,Lipsitz SR,Molenberghs G,Ibrahim JG

更新日期：2001-03-01 00:00:00

abstract：:We introduce two test procedures for comparing two survival distributions on the basis of randomly right-censored data consisting of both paired and unpaired observations. Our procedures are based on generalizations of a pooled rank test statistic previously proposed for uncensored data. One generalization adapts the ...

journal_title：Biometrics

authors： Dallas MJ,Rao PV

更新日期：2000-03-01 00:00:00

abstract：:Motivated by the spatial modeling of aberrant crypt foci (ACF) in colon carcinogenesis, we consider binary data with probabilities modeled as the sum of a nonparametric mean plus a latent Gaussian spatial process that accounts for short-range dependencies. The mean is modeled in a general way using regression splines....

journal_title：Biometrics

authors： Apanasovich TV,Ruppert D,Lupton JR,Popovic N,Turner ND,Chapkin RS,Carroll RJ

更新日期：2008-06-01 00:00:00

abstract：:Markov chain models are frequently used for studying event histories that include transitions between several states. An empirical transition matrix for nonhomogeneous Markov chains has previously been developed, including a detailed statistical theory based on counting processes and martingales. In this article, we s...

journal_title：Biometrics

authors： Aalen OO,Borgan O,Fekjaer H

更新日期：2001-12-01 00:00:00

abstract：:Phase I trials to study the pharmacokinetic properties of a new drug generally involve a restricted number of healthy volunteers. Because of the nature of the group involved in such studies, the appropriate distributional assumptions are not always obvious. These model assumptions include the actual distribution but a...

journal_title：Biometrics

authors： Lindsey JK,Byrom WD,Wang J,Jarvis P,Jones B

更新日期：2000-03-01 00:00:00

abstract：:Image-on-image regression analysis, using images to predict images, is a challenging task, due to (1) the high dimensionality and (2) the complex spatial dependence structures in image predictors and image outcomes. In this work, we propose a novel image-on-image regression model, by extending a spatial Bayesian laten...

journal_title：Biometrics

authors： Guo C,Kang J,Johnson TD

更新日期：2020-12-27 00:00:00

abstract：:Microarray technology allows the monitoring of expression levels of thousands of genes simultaneously. A semiparametric location and scale model is proposed to model gene expression levels for normalization and significance analysis purposes. Robust estimation based on weighted least absolute deviation regression and ...

journal_title：Biometrics

authors： Ma S,Kosorok MR,Huang J,Xie H,Manzella L,Soares MB

更新日期：2006-06-01 00:00:00

abstract：:We propose optimal choice of the design parameters for random discontinuation designs (RDD) using a Bayesian decision-theoretic approach. We consider applications of RDDs to oncology phase II studies evaluating activity of cytostatic agents. The design consists of two stages. The preliminary open-label stage treats al...

journal_title：Biometrics

authors： Trippa L,Rosner GL,Müller P

更新日期：2012-03-01 00:00:00

abstract：:Long-term follow-up is common in many medical investigations where the interest lies in predicting patients' risks for a future adverse outcome using repeatedly measured predictors over time. A key quantity is the likelihood of developing an adverse outcome among individuals who survived up to time s given their covar...

journal_title：Biometrics

authors： Maziarz M,Heagerty P,Cai T,Zheng Y

更新日期：2017-03-01 00:00:00