The impact of heterogeneity on the comparison of survival times.

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：:Tree-based methods have become popular for analyzing complex data structures where the primary goal is risk stratification of patients. Ensemble techniques improve the accuracy in prediction and address the instability in a single tree by growing an ensemble of trees and aggregating. However, in the process, individua...

journal_title：Statistics in medicine

authors： Banerjee M,Ding Y,Noone AM

更新日期：2012-07-10 00:00:00

abstract：:We describe the usual statistical concepts and consequent appropriate simulations of a prospective study for the simple case of a single risk variable and an assumed logistic model. We examine the simulations of Lilienfeld and Pyne, and show that they are seriously flawed. Contrary to those authors' claims, the estima...

journal_title：Statistics in medicine

authors： Halperin M,Abbott RD,Blackwelder WC,Jacobowitz R,Lan KK,Verter JI,Wedel H

更新日期：1985-04-01 00:00:00

abstract：:Correlated data are obtained in longitudinal epidemiological studies, where repeated measurements are taken on individuals or groups over time. Such longitudinal data are ideally analyzed using multilevel modeling approaches, which appropriately account for the correlations in repeated responses in the same individual...

journal_title：Statistics in medicine

authors： Xanthakis V,Sullivan LM,Vasan RS

更新日期：2013-12-10 00:00:00

abstract：:In this paper we give an informal introduction to a robust method for survival analysis which is based on a modification of the usual partial likelihood estimator (PLE). Large sample results lead us to expect reduced bias for this robust estimator compared with the PLE whenever there are even slight violations of the ...

journal_title：Statistics in medicine

authors： Minder CE,Bednarski T

更新日期：1996-05-30 00:00:00

abstract：:A few large multi-centre male-only heart trials done in the 1970s and 1980s have been seen as ill-conceived because they did not include females. The purpose here is to revisit two of those trials and to consider consequences in terms of cost and power had they been designed to include females. ...

journal_title：Statistics in medicine

authors： Meinert CL

更新日期：1999-02-15 00:00:00

abstract：:Before introducing a new measurement tool it is necessary to evaluate its performance. Several statistical methods have been developed, or used, to evaluate the reliability and validity of a new assessment method in such circumstances. In this paper we review some commonly used methods. Data from a study that was cond...

journal_title：Statistics in medicine

authors： White SA,van den Broek NR

更新日期：2004-05-30 00:00:00

abstract：:Adaptive designs have been proposed for clinical trials in which the nuisance parameters or alternative of interest are unknown or likely to be misspecified before the trial. Although most previous works on adaptive designs and mid-course sample size re-estimation have focused on two-stage or group-sequential designs ...

journal_title：Statistics in medicine

authors： Bartroff J,Lai TL

更新日期：2008-05-10 00:00:00

abstract：:The "some invalid, some valid instrumental variable estimator" (sisVIVE) is a lasso-based method for instrumental variables (IVs) regression of outcome on an exposure. In principle, sisVIVE is robust to some of the IVs in the analysis being invalid, in the sense of being related to the outcome variable through pathway...

journal_title：Statistics in medicine

authors： Bao Y,Clarke PS,Smart M,Kumari M

更新日期：2019-04-30 00:00:00

abstract：:In observational studies with censored data, exposure-outcome associations are commonly measured with adjusted hazard ratios from multivariable Cox proportional hazards models. The difference in restricted mean survival times (RMSTs) up to a pre-specified time point is an alternative measure that offers a clinically m...

journal_title：Statistics in medicine

authors： Conner SC,Sullivan LM,Benjamin EJ,LaValley MP,Galea S,Trinquart L

更新日期：2019-09-10 00:00:00

abstract：:Toxicity probability interval designs have received increasing attention as a dose-finding method in recent years. In this study, we compared the two-stage, likelihood-based continual reassessment method (CRM), modified toxicity probability interval (mTPI), and the Bayesian optimal interval design (BOIN) in order to e...

journal_title：Statistics in medicine

authors： Horton BJ,Wages NA,Conaway MR

更新日期：2017-01-30 00:00:00

abstract：:Competing compartment models of different complexities have been used for the quantitative analysis of dynamic contrast-enhanced magnetic resonance imaging data. We present a spatial elastic net approach that allows to estimate the number of compartments for each voxel such that the model complexity is not fixed a pri...

journal_title：Statistics in medicine

authors： Sommer JC,Gertheiss J,Schmid VJ

更新日期：2014-03-15 00:00:00

abstract：:The problem for assessing biosimilarity and drug interchangeability of follow-on biologics (biosimilar products) is studied. Unlike the generic products, the development of biosimilar products is much more complicated because of fundamental differences in functional structures and manufacturing processes. As a result,...

journal_title：Statistics in medicine

authors： Chow SC,Wang J,Endrenyi L,Lachenbruch PA

更新日期：2013-02-10 00:00:00

abstract：:Important differences between explanatory and pragmatic studies were originally argued by Schwartz and Lellouch. Three important differences between the two types of study involve study control, study violators and inclusion criteria. It was originally argued that explanatory studies are highly controlled, and pragmat...

journal_title：Statistics in medicine

authors： McMahon AD

更新日期：2002-05-30 00:00:00

abstract：:Outcomes research often requires estimating the impact of a binary treatment on a binary outcome in a non-randomized setting, such as the effect of taking a drug on mortality. The data often come from self-selected samples, leading to a spurious correlation between the treatment and outcome when standard binary depend...

journal_title：Statistics in medicine

authors： Bhattacharya J,Goldman D,McCaffrey D

更新日期：2006-02-15 00:00:00

abstract：:Recurrent event data are commonly encountered in health-related longitudinal studies. In this paper time-to-events models for recurrent event data are studied with non-informative and informative censorings. In statistical literature, the risk set methods have been confirmed to serve as an appropriate and efficient ap...

journal_title：Statistics in medicine

authors： Wang MC,Chiang CT

更新日期：2002-02-15 00:00:00

abstract：:Regression to the mean arises often in statistical applications where the units chosen for study relate to some observed characteristic in the extreme of its distribution. Gardner and Heady attribute the effect of regression to the mean to measurement errors. They assume the model Yi = U + ei, where U is a fixed withi...

journal_title：Statistics in medicine

authors： Johnson WD,George VT

更新日期：1991-08-01 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：:It is naive and incorrect to use the proportions of successful operations to compare the performance of surgeons because the patients' risk profiles are different. In this paper, we explore the use of risk-adjusted procedures to compare the performance of surgeons. One such risk-adjusted statistic is the standardized ...

journal_title：Statistics in medicine

authors： Tang X,Gan FF

更新日期：2017-07-20 00:00:00

abstract：:In the comparison of two or more treatment groups to a control group, consider a study with non-decreasing repeated measurements of the same characteristic taken over a common set of time points for each subject. Based on the vector of possibly incomplete responses from each subject, this paper considers asymptoticall...

journal_title：Statistics in medicine

authors： Davis CS

更新日期：1996-12-15 00:00:00

abstract：:Many studies have reported large variations in age- and sex-adjusted rates of hospitalizations across small geographic areas. These variations have often been attributed to differences in medical practice style which are not reflected in differences in health care outcomes. There is, however, another potentially impor...

journal_title：Statistics in medicine

authors： Peköz EA,Shwartz M,Iezzoni LI,Ash AS,Posner MA,Restuccia JD

更新日期：2003-05-30 00:00:00

abstract：:The authors measure the efficacy of three methods for predicting the time to infection for susceptible individuals in a population undergoing an HIV epidemic. The methods differ in whether they require detailed information of the contact network and whether they require knowledge of the initial source of infection. Ef...

journal_title：Statistics in medicine

authors： Altmann M,Wee BC,Willard K,Peterson D,Gatewood LC

更新日期：1994-01-15 00:00:00

abstract：:There is an increasing interest in the use of propensity score methods to estimate causal effects in observational studies. However, recent systematic reviews have demonstrated that propensity score methods are inconsistently used and frequently poorly applied in the medical literature. In this study, we compared the ...

journal_title：Statistics in medicine

authors： Austin PC,Mamdani MM

更新日期：2006-06-30 00:00:00

abstract：:Estimates of transmission probabilities for sexually transmitted diseases historically come from studies of uninfected individuals exposed to those with a high disease prevalence (for example, prostitutes). However, changes in sexual behaviour, much of which relates to concerns about AIDS, has made identification of p...

journal_title：Statistics in medicine

authors： Katz BP

更新日期：1992-03-01 00:00:00

abstract：:We describe rank-based approaches to assess principal stratification treatment effects in studies where the outcome of interest is only well-defined in a subgroup selected after randomization. Our methods are sensitivity analyses, in that estimands are identified by fixing a parameter and then we investigate the sensi...

journal_title：Statistics in medicine

authors： Lu X,Mehrotra DV,Shepherd BE

更新日期：2013-11-20 00:00:00

abstract：:In a variety of biomedical applications, particularly those involving screening for infectious diseases, testing individuals (e.g. blood/urine samples, etc.) in pools has become a standard method of data collection. This experimental design, known as group testing (or pooled testing), can provide a large reduction in ...

journal_title：Statistics in medicine

authors： Chen P,Tebbs JM,Bilder CR

更新日期：2009-10-15 00:00:00

abstract：:A new, intuitive method has recently been proposed to explore treatment-covariate interactions in survival data arising from two treatment arms of a clinical trial. The method is based on constructing overlapping subpopulations of patients with respect to one (or more) covariates of interest and in observing the patte...

journal_title：Statistics in medicine

authors： Bonetti M,Zahrieh D,Cole BF,Gelber RD

更新日期：2009-04-15 00:00:00

abstract：:Our objective is to develop a model to estimate the relative risk of disease in each area, Ai, i=1, ... , n, of a region and to identify areas of unusually high or low risk. We use a product partition model (PPM) in which we assume that the true relative risks can be partitioned into a number of components or sets of ...

journal_title：Statistics in medicine

authors： Hegarty A,Barry D

更新日期：2008-08-30 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：:In genetic and genomic studies, gene-environment (G×E) interactions have important implications. Some of the existing G×E interaction methods are limited by analyzing a small number of G factors at a time, by assuming linear effects of E factors, by assuming no data contamination, and by adopting ineffective selection...

journal_title：Statistics in medicine

authors： Wu C,Shi X,Cui Y,Ma S

更新日期：2015-12-30 00:00:00