Analysis of current status data with missing covariates.

abstract：:We consider methods for estimating the treatment effect and/or the covariate by treatment interaction effect in a randomized clinical trial under noncompliance with time-to-event outcome. As in Cuzick et al. (2007), assuming that the patient population consists of three (possibly latent) subgroups based on treatment p...

journal_title：Biometrics

authors： Li S,Gray RJ

更新日期：2016-09-01 00:00:00

abstract：:High throughput technologies, such as gene expression arrays and protein mass spectrometry, allow one to simultaneously evaluate thousands of potential biomarkers that could distinguish different tissue types. Of particular interest here is distinguishing between cancerous and normal organ tissues. We consider statist...

journal_title：Biometrics

authors： Pepe MS,Longton G,Anderson GL,Schummer M

更新日期：2003-03-01 00:00:00

abstract：:Tsiatis, Rosner, and Mehta (1984, Biometrics 40, 797-803) proposed a procedure for constructing confidence intervals following group sequential tests of a normal mean. This method is first extended for group sequential tests for which the sample sizes between interim analyses are not identical or the times are not equ...

journal_title：Biometrics

authors： Kim K,DeMets DL

更新日期：1987-12-01 00:00:00

abstract：:The accuracy of a new diagnostic test is often determined by comparison with a reference test which also has unknown error rates. Maximum likelihood estimation of the error rates of both tests is possible if they are simultaneously applied to two populations with different disease prevalences. The estimation procedure...

journal_title：Biometrics

authors： Vacek PM

更新日期：1985-12-01 00:00:00

abstract：:Directed acyclic graphical (DAG) models are increasingly employed in the study of physical and biological systems to model direct influences between variables. Identifying the graph from data is a challenging endeavor, which can be more reasonably tackled if the variables are assumed to satisfy a given ordering; in th...

journal_title：Biometrics

authors： Altomare D,Consonni G,La Rocca L

更新日期：2013-06-01 00:00:00

abstract：:We propose a Bayesian latent Ornstein-Uhlenbeck (OU) model to analyze unbalanced longitudinal data of binary and ordinal variables, which are manifestations of fewer continuous latent variables. We focus on the evolution of such latent variables when they continuously change over time. Existing approaches are limited ...

journal_title：Biometrics

authors： Tran TD,Lesaffre E,Verbeke G,Duyck J

更新日期：2020-05-11 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：:This paper describes methodology for analyzing data from cluster randomized trials with count outcomes, taking indirect effects as well spatial effects into account. Indirect effects are modeled using a novel application of a measure of depth within the intervention arm. Both direct and indirect effects can be estimat...

journal_title：Biometrics

authors： Anaya-Izquierdo K,Alexander N

更新日期：2020-06-18 00:00:00

abstract：:The "biometric school" founded by K. Pearson, F. Galton, and W. F. R. Weldon was concerned especially with heredity and variation, and between the wars "biometry" was not widely used as a general term for quantitative biology. The foundation of the Biometric Society encouraged this wider usage, and medical and biologi...

journal_title：Biometrics

authors： Armitage P

更新日期：1985-12-01 00:00:00

abstract：:In many applications of generalized linear mixed models to multilevel data, it is of interest to test whether a random effects variance component is zero. It is well known that the usual asymptotic chi-square distribution of the likelihood ratio and score statistics under the null does not necessarily hold. In this no...

journal_title：Biometrics

authors： Fitzmaurice GM,Lipsitz SR,Ibrahim JG

更新日期：2007-09-01 00:00:00

abstract：:Pocock et al. (2012, European Heart Journal 33, 176-182) proposed a win ratio approach to analyzing composite endpoints comprised of outcomes with different clinical priorities. In this article, we establish a statistical framework for this approach. We derive the null hypothesis and propose a closed-form variance est...

journal_title：Biometrics

authors： Luo X,Tian H,Mohanty S,Tsai WY

更新日期：2015-03-01 00:00:00

abstract：:This paper proposes a two-stage phase I-II clinical trial design to optimize dose-schedule regimes of an experimental agent within ordered disease subgroups in terms of the toxicity-efficacy trade-off. The design is motivated by settings where prior biological information indicates it is certain that efficacy will imp...

journal_title：Biometrics

authors： Lin R,Thall PF,Yuan Y

更新日期：2020-03-01 00:00:00

abstract：:Array-based CGH experiments are designed to detect genomic aberrations or regions of DNA copy-number variation that are associated with an outcome, typically a state of disease. Most of the existing statistical methods target on detecting DNA copy number variations in a single sample or array. We focus on the detectio...

journal_title：Biometrics

authors： Hu J,Zhang L,Wang HJ

更新日期：2016-09-01 00:00:00

abstract：:Objective measures of oxygen consumption and carbon dioxide production by mammals are used to predict their energy expenditure. Since energy expenditure is not directly observable, it can be viewed as a latent construct with multiple physical indirect measures such as respiratory quotient, volumetric oxygen consumptio...

journal_title：Biometrics

authors： Tekwe CD,Zoh RS,Bazer FW,Wu G,Carroll RJ

更新日期：2018-03-01 00:00:00

abstract：:The spending function approach proposed by Lan and DeMets (1983, Biometrika 70, 659-663) for sequential monitoring of clinical trials is applied to situations where comparison of changes in a continuous response variable between two groups is the primary concern. Death, loss to follow-up, and missed visits could cause...

journal_title：Biometrics

authors： Wu MC,Lan KK

更新日期：1992-09-01 00:00:00

abstract：:Many problems that appear in biomedical decision-making, such as diagnosing disease and predicting response to treatment, can be expressed as binary classification problems. The support vector machine (SVM) is a popular classification technique that is robust to model misspecification and effectively handles high-dime...

journal_title：Biometrics

authors： Luckett DJ,Laber EB,El-Kamary SS,Fan C,Jhaveri R,Perou CM,Shebl FM,Kosorok MR

更新日期：2020-08-31 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：:This article introduces an original methodology based on empirical likelihood, which aims at combining different food contamination and consumption surveys to provide risk managers with a risk measure, taking into account all the available information. This risk index is defined as the probability that exposure to a c...

journal_title：Biometrics

authors： Crépet A,Harari-Kermadec H,Tressou J

更新日期：2009-03-01 00:00:00

abstract：:Epidemiolgic studies have strongly suggested that a vast majority (80-90%) of cancers are caused by radiation, chemical and biologic agents; the remainder result from endogenous or genetic factors. Biologically, cancer is most probably the end result of a complex multistage process and therefore may be due to a sequen...

journal_title：Biometrics

authors： Lilienfeld AM

更新日期：1982-03-01 00:00:00

abstract：:The relative performance of the unconditioned maximum likelihood estimators (UMLEs), conditional MLEs (CMLEs), and Jewell-type estimators of the odds ratio (OR) and its logarithm were investigated in sets of single 2 x 2 contingency tables. The tables were generated by complete enumeration of all possible cell frequen...

journal_title：Biometrics

authors： Walter SD,Cook RJ

更新日期：1991-09-01 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：:Normality of random effects is a routine assumption for the linear mixed model, but it may be unrealistic, obscuring important features of among-individual variation. We relax this assumption by approximating the random effects density by the seminonparameteric (SNP) representation of Gallant and Nychka (1987, Econome...

journal_title：Biometrics

authors： Zhang D,Davidian M

更新日期：2001-09-01 00:00:00

abstract：:Interval-censored failure time data occur in many fields such as demography, economics, medical research, and reliability and many inference procedures on them have been developed (Sun, 2006; Chen, Sun, and Peace, 2012). However, most of the existing approaches assume that the mechanism that yields interval censoring ...

journal_title：Biometrics

authors： Wang P,Zhao H,Sun J

更新日期：2016-12-01 00:00:00

abstract：:A novel nonparametric regression model is developed for evaluating the covariate-specific accuracy of a continuous biological marker. Accurately screening diseased from nondiseased individuals and correctly diagnosing disease stage are critically important to health care on several fronts, including guiding recommenda...

journal_title：Biometrics

authors： Inácio de Carvalho V,de Carvalho M,Branscum AJ

更新日期：2017-12-01 00:00:00

abstract：:Pharmacovigilance systems aim at early detection of adverse effects of marketed drugs. They maintain large spontaneous reporting databases for which several automatic signaling methods have been developed. One limit of those methods is that the decision rules for the signal generation are based on arbitrary thresholds...

journal_title：Biometrics

authors： Ahmed I,Dalmasso C,Haramburu F,Thiessard F,Broët P,Tubert-Bitter P

更新日期：2010-03-01 00:00:00

abstract：:Tag loss in mark-recapture experiments is a violation of one of the Jolly-Seber model assumptions. It causes bias in parameter estimates and has only been dealt with in an ad hoc manner. We develop methodology to estimate tag retention and abundance in double-tagging mark-recapture experiments. We apply this methodolo...

journal_title：Biometrics

authors： Cowen L,Schwarz CJ

更新日期：2006-09-01 00:00:00

abstract：:Identifying factors associated with increased medical cost is important for many micro- and macro-institutions, including the national economy and public health, insurers and the insured. However, assembling comprehensive national databases that include both the cost and individual-level predictors can prove challengi...

journal_title：Biometrics

authors： Johnson BA,Long Q,Huang Y,Chansky K,Redman M

更新日期：2016-09-01 00:00:00

abstract：:This article demonstrates semiparametric maximum likelihood estimation of a nonlinear growth model for fish lengths using imprecisely measured ages. Data on the species corvina reina, found in the Gulf of Nicoya, Costa Rica, consist of lengths and imprecise ages for 168 fish and precise ages for a subset of 16 fish. T...

journal_title：Biometrics

authors： Suh EY,Schafer DW

更新日期：2002-06-01 00:00:00

abstract：:Receiver operating characteristic (ROC) analysis is widely used to evaluate the performance of diagnostic tests with continuous or ordinal responses. A popular study design for assessing the accuracy of diagnostic tests involves multiple readers interpreting multiple diagnostic test results, called the multi-reader, m...

journal_title：Biometrics

authors： Kim E,Zhang Z,Wang Y,Zeng D

更新日期：2014-12-01 00:00:00

abstract：:Motivated by the particular problem of predicting defoliation based on a measure of gypsy moth egg mass density, prediction in the presence of measurement error is discussed. The measurement error variances and covariances are allowed to vary from unit to unit and are estimated by some type of within unit sampling. A ...

journal_title：Biometrics

authors： Buonaccorsi JP

更新日期：1995-12-01 00:00:00