Estimating treatment effect in a proportional hazards model in randomized clinical trials with all-or-nothing compliance.

abstract：:Johnson and Wehrly (1978, Journal of the American Statistical Association 73, 602-606) and Wehrly and Johnson (1980, Biometrika 67, 255-256) show one way to construct the joint distribution of a circular and a linear random variable, or the joint distribution of a pair of circular random variables from their marginal ...

journal_title：Biometrics

authors： Fernández-Durán JJ

更新日期：2007-06-01 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：:The estimation of maternal genetic variances by a multivariate maximum likelihood method is discussed. As an illustration the method is applied to data on Tribolium using a model based on partitioning the maternal genetic effect into additive and dominance components. An alternative model due to Falconer (1965) is als...

journal_title：Biometrics

authors： Thompson R

更新日期：1976-12-01 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：:Unless the true association is very strong, simple large-sample confidence intervals for the odds ratio based on the delta method perform well even for small samples. Such intervals include the Woolf logit interval and the related Gart interval based on adding .5 before computing the log odds ratio estimate and its st...

journal_title：Biometrics

authors： Agresti A

更新日期：1999-06-01 00:00:00

abstract：:Prognostic models in survival analysis typically aim to describe the association between patient covariates and future outcomes. More recently, efforts have been made to include covariate information that is updated over time. However, there exists as yet no standard approach to assess the predictive accuracy of such ...

journal_title：Biometrics

authors： Schoop R,Graf E,Schumacher M

更新日期：2008-06-01 00:00:00

abstract：:As ultra high-dimensional longitudinal data are becoming ever more apparent in fields such as public health and bioinformatics, developing flexible methods with a sparse model is of high interest. In this setting, the dimension of the covariates can potentially grow exponentially as ...

journal_title：Biometrics

authors： Green B,Lian H,Yu Y,Zu T

更新日期：2020-08-04 00:00:00

abstract：:In this article, we study nonparametric estimation of the mean function of a counting process with panel observations. We introduce the gamma frailty variable to account for the intracorrelation between the panel counts of the counting process and construct a maximum pseudo-likelihood estimate with the frailty variabl...

journal_title：Biometrics

authors： Zhang Y,Jamshidian M

更新日期：2003-12-01 00:00:00

abstract：:A stochastic model is presented for the analysis of incomplete repeated-measures experiments. The general linear model is used to relate the response measures to other variables which are thought to account for inherent variation; an autoregressive moving average (ARMA) time series representation is used to model dist...

journal_title：Biometrics

authors： Rochon J,Helms RW

更新日期：1989-03-01 00:00:00

abstract：:We consider a semiparametric regression model that relates a normal outcome to covariates and a genetic pathway, where the covariate effects are modeled parametrically and the pathway effect of multiple gene expressions is modeled parametrically or nonparametrically using least-squares kernel machines (LSKMs). This un...

journal_title：Biometrics

authors： Liu D,Lin X,Ghosh D

更新日期：2007-12-01 00:00:00

abstract：:We explore the use of a posterior predictive loss criterion for model selection for incomplete longitudinal data. We begin by identifying a property that most model selection criteria for incomplete data should consider. We then show that a straightforward extension of the Gelfand and Ghosh (1998, Biometrika, 85, 1-11...

journal_title：Biometrics

authors： Daniels MJ,Chatterjee AS,Wang C

更新日期：2012-12-01 00:00:00

abstract：:Receiver operating characteristic (ROC) curves are frequently used to assess the usefulness of diagnostic markers. When several diagnostic markers are available, they can be combined by a best linear combination: that is, when the area under the ROC curve of this combination is maximized among all possible linear comb...

journal_title：Biometrics

authors： Reiser B,Faraggi D

更新日期：1997-06-01 00:00:00

abstract：:When a true survival endpoint cannot be assessed for some subjects, an alternative endpoint that measures the true endpoint with error may be collected, which often occurs when obtaining the true endpoint is too invasive or costly. We develop an estimated likelihood function for the situation where we have both uncert...

journal_title：Biometrics

authors： Zee J,Xie SX

更新日期：2015-09-01 00:00:00

abstract：:It is not, in general, possible to include all relevant risk factors in a model of survival or disease incidence. This heterogeneity must be accounted for in the interpretation, as it can imply otherwise unexpected results. This is illustrated by diabetic nephropathy, a serious complication experienced by some diabeti...

journal_title：Biometrics

authors： Hougaard P,Myglegaard P,Borch-Johnsen K

更新日期：1994-12-01 00:00:00

abstract：:We consider modeling correlated survival data when cluster sizes may be informative to the outcome of interest based on a within-cluster resampling (WCR) approach and a weighted score function (WSF) method. We derive the large sample properties for the WCR estimators under the Cox proportional hazards model. We establ...

journal_title：Biometrics

authors： Cong XJ,Yin G,Shen Y

更新日期：2007-09-01 00:00:00

abstract：:We consider the problem of testing for a dose-related effect based on a candidate set of (typically nonlinear) dose-response models using likelihood-ratio tests. For the considered models this reduces to assessing whether the slope parameter in these nonlinear regression models is zero or not. A technical problem is t...

journal_title：Biometrics

authors： Gutjahr G,Bornkamp B

更新日期：2017-03-01 00:00:00

abstract：:Computer simulation has been used to compare four methods for calculating confidence intervals for simple rate ratios estimated from cohort studies. The method proposed by Cornfield (1956. In Proceedings of the Third Berkeley Symposium on Mathematical Statistics and Probability. Vol. IV, 135-148) for interval estimati...

journal_title：Biometrics

authors： Howe GR

更新日期：1983-06-01 00:00:00

abstract：:Several models for the course of microbial infections during the incubation period are examined. Each model fits sore throat incubation data very well. Together with the lack of precision of the resulting parameter estimates, this suggests that incubation data alone are insufficient for elucidating the finer details o...

journal_title：Biometrics

authors： Morgan BJ,Watts SA

更新日期：1980-06-01 00:00:00

abstract：:In studying the relationship between an ordered categorical predictor and an event time, it is standard practice to include dichotomous indicators of the different levels of the predictor in a Cox model. One can then use a multiple degree-of-freedom score or partial likelihood ratio test for hypothesis testing. Often,...

journal_title：Biometrics

authors： Dunson DB,Herring AH

更新日期：2003-12-01 00:00:00

abstract：:Interference occurs between individuals when the treatment (or exposure) of one individual affects the outcome of another individual. Previous work on causal inference methods in the presence of interference has focused on the setting where it is a priori assumed that there is "partial interference," in the sense that...

journal_title：Biometrics

authors： Loh WW,Hudgens MG,Clemens JD,Ali M,Emch ME

更新日期：2020-03-01 00:00:00

abstract：:In this article, we propose approximate sample size formulas for establishing equivalence or noninferiority of two treatments in match-pairs design. Using the ratio of two proportions as the equivalence measure, we derive sample size formulas based on a score statistic for two types of analyses: hypothesis testing and...

journal_title：Biometrics

authors： Tang ML,Tang NS,Chan IS,Chan BP

更新日期：2002-12-01 00:00:00

abstract：:Recurrent events data are commonly encountered in medical studies. In many applications, only the number of events during the follow-up period rather than the recurrent event times is available. Two important challenges arise in such studies: (a) a substantial portion of subjects may not experience the event, and (b) ...

journal_title：Biometrics

authors： Diao G,Zeng D,Hu K,Ibrahim JG

更新日期：2019-12-01 00:00:00

abstract：:Diggle's tests of spatial randomness based on empirical distributions of interpoint distances can be performed with and without edge-effect correction. We present here numerical results illustrating that tests without the edge-effect correction proposed by Diggle (1979, Biometrics 35, 87-101) have a higher power for s...

journal_title：Biometrics

authors： Gignoux J,Duby C,Barot S

更新日期：1999-03-01 00:00:00

abstract：SUMMARY:We develop sample size formulas for studies aiming to test mean differences between a treatment and control group when all-or-none nonadherence (noncompliance) and selection bias are expected. Recent work by Fay, Halloran, and Follmann (2007, Biometrics 63, 465-474) addressed the increased variances within grou...

journal_title：Biometrics

authors： Shardell MD,El-Kamary SS

更新日期：2009-06-01 00:00:00

abstract：:A multiple toxicity model for the quantal response of organisms is constructed based on an existing bivariate theory. The main assumption is that the tolerances follow a multivariate normal distribution function. However, any monotone tolerance distribution can be applied by mapping the integration region in the n-dim...

journal_title：Biometrics

authors： Christensen ER,Chen CY

更新日期：1985-09-01 00:00:00

abstract：:In an analysis of capture-recapture data, the identification of a model that fits is a critical step. For the multisite (also called multistate) models used to analyze data gathered at several sites, no reliable test for assessing fit is currently available. We propose a test for the JMV model, a simple generalization...

journal_title：Biometrics

authors： Pradel R,Wintrebert CM,Gimenez O

更新日期：2003-03-01 00:00:00

abstract：:Functional mapping is a useful tool for mapping quantitative trait loci (QTL) that control dynamic traits. It incorporates mathematical aspects of biological processes into the mixture model-based likelihood setting for QTL mapping, thus increasing the power of QTL detection and the precision of parameter estimation. ...

journal_title：Biometrics

authors： Yang J,Wu R,Casella G

更新日期：2009-03-01 00:00:00

abstract：:To evaluate diagnostic tests, one would ideally like to verify, for example, with a biopsy, the disease state of all subjects in a study. Often, however, no all subjects are verified. Previous methods for evaluation assume that the decision to verify depends only on recorded variables. Sometimes, particularly if the d...

journal_title：Biometrics

authors： Baker SG

更新日期：1995-03-01 00:00:00

abstract：:The validation of surrogate endpoints has been studied by Prentice (1989, Statistics in Medicine 8, 431-440) and Freedman, Graubard, and Schatzkin (1992, Statistics in Medicine 11, 167-178). We extended their proposals in the cases where the surrogate and the final endpoints are both binary or normally distributed. Le...

journal_title：Biometrics

authors： Buyse M,Molenberghs G

更新日期：1998-09-01 00:00:00

abstract：:In this article, we present an estimation approach for solving nonlinear constrained generalized estimating equations that can be implemented using object-oriented software for nonlinear programming, such as nlminb in Splus or fmincon and lsqnonlin in Matlab. We show how standard estimating equation theory includes th...

journal_title：Biometrics

authors： Contreras M,Ryan LM

更新日期：2000-12-01 00:00:00