Structured correlation in models for clustered data.

abstract：:The receiver operating characteristic (ROC) curve is a popular technique with applications, for example, investigating an accuracy of a biomarker to delineate between disease and non-disease groups. A common measure of accuracy of a given diagnostic marker is the area under the ROC curve (AUC). In contrast with the AU...

journal_title：Statistics in medicine

authors： Yu J,Yang L,Vexler A,Hutson AD

更新日期：2016-06-15 00:00:00

abstract：:Prevention studies, as distinguished from studies investigating treatments for established disease, present some distinct challenges. Perhaps the most extensive experience with preventive agents is in the area of infectious diseases; vaccines have been extremely effective in preventing many such diseases. Vaccines hav...

journal_title：Statistics in medicine

authors： Ellenberg SS

更新日期：2004-01-30 00:00:00

abstract：:Estimation and group comparison of survival curves are two very common issues in survival analysis. In practice, the Kaplan-Meier estimates of survival functions may be biased due to unbalanced distribution of confounders. Here we develop an adjusted Kaplan-Meier estimator (AKME) to reduce confounding effects using in...

journal_title：Statistics in medicine

authors： Xie J,Liu C

更新日期：2005-10-30 00:00:00

abstract：:Disease incidence or disease mortality rates for small areas are often displayed on maps. Maps of raw rates, disease counts divided by the total population at risk, have been criticized as unreliable due to non-constant variance associated with heterogeneity in base population size. This has led to the use of model-ba...

journal_title：Statistics in medicine

authors： Stern HS,Cressie N

更新日期：2000-09-15 00:00:00

abstract：:Many extensions of survival models based on the Cox proportional hazards approach have been proposed to handle clustered or multiple event data. Of particular note are five Cox-based models for recurrent event data: Andersen and Gill (AG); Wei, Lin and Weissfeld (WLW); Prentice, Williams and Peterson, total time (PWP-...

journal_title：Statistics in medicine

authors： Kelly PJ,Lim LL

更新日期：2000-01-15 00:00:00

abstract：:In biomedical studies and clinical trials, repeated measures are often subject to some upper and/or lower limits of detection. Hence, the responses are either left or right censored. A complication arises when more than one series of responses is repeatedly collected on each subject at irregular intervals over a perio...

journal_title：Statistics in medicine

authors： Lachos VH,A Matos L,Castro LM,Chen MH

更新日期：2019-03-15 00:00:00

abstract：:Recently, there has been much work on early phase cancer designs that incorporate both toxicity and efficacy data, called phase I-II designs because they combine elements of both phases. However, they do not explicitly address the phase II hypothesis test of H0 : p ≤ p0 , where p is the probability of efficacy at the ...

journal_title：Statistics in medicine

authors： Bartroff J,Lai TL,Narasimhan B

更新日期：2014-07-20 00:00:00

abstract：:Multi-state models are useful for modelling disease progression where the state space of the process is used to represent the discrete disease status of subjects. Often, the disease process is only observed at clinical visits, and the schedule of these visits can depend on the disease status of patients. In such situa...

journal_title：Statistics in medicine

authors： Lesperance ML,Sabelnykova V,Nathoo FS,Lau F,Downing MG

更新日期：2015-12-20 00:00:00

abstract：:We propose a new, less costly, design to test the equivalence of digital versus analogue mammography in terms of sensitivity and specificity. Because breast cancer is a rare event among asymptomatic women, the sample size for testing equivalence of sensitivity is larger than that for testing equivalence of specificity...

journal_title：Statistics in medicine

authors： Baker SG,Connor RJ,Kessler LG

更新日期：1998-10-15 00:00:00

abstract：:Hierarchical regression analysis holds much promise for epidemiologic analysis, but has as yet seen limited application because of lack of easily used software and the relatively lengthy run times of preferred fitting methods (such as true maximum likelihood and Bayesian approaches). This paper compares three relative...

journal_title：Statistics in medicine

authors： Greenland S

更新日期：1997-03-15 00:00:00

abstract：:A method is proposed to infer the randomized treatment effect on survival after an adjustment for a post-randomization variable. The post-randomization variable is made independent of the treatment assignment and is considered a surrogate for baseline prognostic factors. The relationship between the post-randomization...

journal_title：Statistics in medicine

authors： Heller G

更新日期：2001-11-30 00:00:00

abstract：:This paper describes the Stoke Index which has been designed to give a global measure of disease activity in rheumatoid arthritis. The index is based on two objective laboratory measurements, one subjective and two semi-objective clinical measurements, chosen from 13 measurements using clinical judgement. Variable sel...

journal_title：Statistics in medicine

authors： Jones PW,Ziade MF,Davis MJ,Dawes PT

更新日期：1993-06-30 00:00:00

abstract：:In natural history studies of chronic disease, it is of interest to understand the evolution of key variables that measure aspects of disease progression. This is particularly true for immunological variables among persons infected with the human immunodeficiency virus (HIV). The natural time scale for such studies is...

journal_title：Statistics in medicine

authors： Vittinghoff E,Malani HM,Jewell NP

更新日期：1994-06-15 00:00:00

abstract：:We analyze data obtained from a study designed to evaluate training effects on the performance of certain motor activities of Parkinson's disease patients. Maximum likelihood methods were used to fit beta-binomial/Poisson regression models tailored to evaluate the effects of training on the numbers of attempted and su...

journal_title：Statistics in medicine

authors： Lora MI,Singer JM

更新日期：2008-07-30 00:00:00

abstract：:We consider evaluation and comparison of the diagnostic accuracy of biomarkers with continuous test outcomes, possibly correlated due to repeated measurements. We develop nonparametric group sequential testing procedures to evaluate and compare the area of biomarkers under their receiver operating characteristic curve...

journal_title：Statistics in medicine

authors： Liu A,Wu C,Schisterman EF

更新日期：2008-05-10 00:00:00

abstract：:Motivated by a study about prompt coronary angiography in myocardial infarction, we propose a method to estimate the causal effect of a treatment in two-arm experimental studies with possible noncompliance in both treatment and control arms. We base the method on a causal model for repeated binary outcomes (before and...

journal_title：Statistics in medicine

authors： Bartolucci F,Farcomeni A

更新日期：2013-11-10 00:00:00

abstract：:Nutritional exposures are often measured with considerable error in commonly used surrogate instruments such as the food frequency questionnaire (FFQ) (denoted by Q(i) for the ith subject). The error can be both systematic and random. The diet record (DR) denoted by R(i) for the ith subject is considered an alloyed go...

journal_title：Statistics in medicine

authors： Rosner B,Michels KB,Chen YH,Day NE

更新日期：2008-08-15 00:00:00

abstract：:In clinical trials, treatment comparisons are often performed by models that incorporate important prognostic factors. Since these models require complete covariate information on all patients, statisticians frequently resort to complete case analysis or to omission of an important covariate. A probability imputation ...

journal_title：Statistics in medicine

authors： Schemper M,Smith TL

更新日期：1990-07-01 00:00:00

abstract：:Hospital length of stay (LOS) is an important measure of healthcare utilization and is generally positively skewed and heterogeneous. We fit a Coxian phase-type distribution to LOS and identify the hidden states of the underlying latent homogeneous Markov model. We demonstrate that selecting an appropriate number of p...

journal_title：Statistics in medicine

authors： Tang X,Luo Z,Gardiner JC

更新日期：2012-06-30 00:00:00

abstract：:In the presence of confounding, the consistency assumption required for identification of causal effects may be violated due to misclassification of the outcome variable. We introduce an inverse probability weighted approach to rebalance covariates across treatment groups while mitigating the influence of differential...

journal_title：Statistics in medicine

authors： Gravel CA,Platt RW

更新日期：2018-02-10 00:00:00

abstract：:Performance of a diagnostic test is ideally evaluated by a comparison of the test results to a gold standard for all the patients in a study. In practice, however, it is common for a subset of study patients to have the gold standard not verified (missing) due to ethical or expense considerations. Sensitivity and spec...

journal_title：Statistics in medicine

authors： Kosinski AS,Chen Y,Lyles RH

更新日期：2010-07-10 00:00:00

abstract：:We provide a Bayesian analysis of data categorized into two levels of age (younger than 50 years, at least 50 years) and three levels of bone mineral density (normal, osteopenia, osteoporosis) for white females at least 20 years old in the third National Health and Nutrition Examination Survey. For the sample, the age...

journal_title：Statistics in medicine

authors： Nandram B,Liu N,Choi JW,Cox L

更新日期：2005-04-15 00:00:00

abstract：:In multiple-record systems estimation it is usually assumed that all registration relate to the same population. In this paper, we develop a method which can be used when the registrations relate to different populations, in the sense that they cover, for example, different time periods or regions. We show that under ...

journal_title：Statistics in medicine

authors： Zwane EN,van der Pal-de Bruin K,van der Heijden PG

更新日期：2004-07-30 00:00:00

abstract：:In many countries, the monitoring of child growth does not occur in a regular manner, and instead, we may have to rely on sporadic observations that are subject to substantial measurement error. In these countries, it can be difficult to identify patterns of poor growth, and faltering children may miss out on essentia...

journal_title：Statistics in medicine

authors： Anderson C,Xiao L,Checkley W

更新日期：2019-08-30 00:00:00

abstract：:The purpose of this research was to develop appropriate methods for analysing repeated ordinal categorical data that arose in an intervention trial to prevent oesophageal cancer. The measured response was the degree of oesophageal dysplasia at 2.5 and 6 years after randomization. An important feature was that some res...

journal_title：Statistics in medicine

authors： Mark SD,Gail MH

更新日期：1994-03-15 00:00:00

abstract：:The publication of Fisher's correspondence on statistics has shed new light on his views on randomization. Quotations from this correspondence and from other works of Fisher are used to illustrate the role of randomization in clinical trials. It is concluded that Fisher's views not only are coherent but, despite havin...

journal_title：Statistics in medicine

authors： Senn S

更新日期：1994-02-15 00:00:00

abstract：:Meta-analysis is the methodology for combining findings from similar research studies asking the same question. When the question of interest involves multiple outcomes, multivariate meta-analysis is used to synthesize the outcomes simultaneously taking into account the correlation between the outcomes. Likelihood-bas...

journal_title：Statistics in medicine

authors： Ma Y,Mazumdar M

更新日期：2011-10-30 00:00:00

abstract：:To update the British growth reference, anthropometric data for weight, height, body mass index (weight/height2) and head circumference from 17 distinct surveys representative of England, Scotland and Wales (37,700 children, age range 23 weeks gestation to 23 years) were analysed by maximum penalized likelihood using ...

journal_title：Statistics in medicine

authors： Cole TJ,Freeman JV,Preece MA

更新日期：1998-02-28 00:00:00

abstract：:To construct a confidence interval for the mean of a log-normal distribution in small samples, we propose likelihood-based approaches - the signed log-likelihood ratio and modified signed log-likelihood ratio methods. Extensive Monte Carlo simulation results show the advantages of the modified signed log-likelihood ra...

journal_title：Statistics in medicine

authors： Wu J,Wong AC,Jiang G

更新日期：2003-06-15 00:00:00

abstract：:In this paper, we consider a full likelihood method to analyze continuous longitudinal responses with non-ignorable non-monotone missing data. We consider a transition probability model for the missingness mechanism. A first-order Markov dependence structure is assumed for both the missingness mechanism and observed d...

journal_title：Statistics in medicine

authors： Liao K,Freres DR,Troxel AB

更新日期：2012-12-10 00:00:00