Spatially regularized estimation for the analysis of dynamic contrast-enhanced magnetic resonance imaging data.

abstract：:Conditional power and predictive power provide estimates of the probability of success at the end of the trial based on the information from the interim analysis. The observed value of the time to event endpoint at the interim analysis could be biased for the true treatment effect due to early censoring, leading to a ...

journal_title：Statistics in medicine

authors： Sun L,Wan Y

更新日期：2018-08-15 00:00:00

abstract：:Data monitoring committees (DMCs) have become an increasingly common component of randomized clinical trials in recent years. As experience has accumulated, and more individuals and organizations have become involved in such activities, a variety of approaches to the operation of such committees has inevitably arisen....

journal_title：Statistics in medicine

authors： Ellenberg SS

更新日期：2001-09-15 00:00:00

abstract：:The use of logistic models for independent binary data has relied first on asymptotic theory and later on exact distributions for small samples. However, the use of logistic models for dependent analysis based on exact analysis is not as common. Moreover, attention is usually given to one-stage clustering. In this pap...

journal_title：Statistics in medicine

authors： Troxler S,Lalonde T,Wilson JR

更新日期：2011-04-15 00:00:00

abstract：:The use of the continual reassessment method (CRM) and other model-based approaches to design Phase I clinical trials has increased owing to the ability of the CRM to identify the maximum tolerated dose better than the 3 + 3 method. However, the CRM can be sensitive to the variance selected for the prior distribution ...

journal_title：Statistics in medicine

authors： Zhang J,Braun TM,Taylor JM

更新日期：2013-06-15 00:00:00

abstract：:It is unclear to what extent the incremental predictive performance of a novel biomarker is impacted by the method used to control for standard predictors. We investigated whether adding a biomarker to a model with a published risk score overestimates its incremental performance as compared to adding it to a multivari...

journal_title：Statistics in medicine

authors： Xanthakis V,Sullivan LM,Vasan RS,Benjamin EJ,Massaro JM,D'Agostino RB Sr,Pencina MJ

更新日期：2014-07-10 00:00:00

abstract：:Timeliness of a public health surveillance system is one of its most important characteristics. The process of predicting the present situation using available incomplete information from surveillance systems has received the term nowcasting and has high public health interest. Generally in Europe, general practitione...

journal_title：Statistics in medicine

authors： Nunes B,Natário I,Lucília Carvalho M

更新日期：2013-07-10 00:00:00

abstract：:Obtaining accurate estimates of the performance of a diagnostic test for some population of patients might be difficult when the sample of subjects used for this purpose is not representative for the whole population. Thus, in the motivating example of this paper a test is evaluated by comparing its results with those...

journal_title：Statistics in medicine

authors： Buzoianu M,Kadane JB

更新日期：2008-06-15 00:00:00

abstract：:A new goodness-of-fit test for the logistic regression model is proposed. It exploits the property of this model that when it is correct, i.e. not misspecified, the parameter estimates are (asymptotically) invariant under reweighting the observations by weights wi that are a function of the binary (0/1) outcomes yi. M...

journal_title：Statistics in medicine

authors： Nagelkerke N,Smits J,le Cessie S,van Houwelingen H

更新日期：2005-01-15 00:00:00

abstract：:We applied a computationally practical form of probit analysis for multiple response variables to data on early childhood development of four psychiatric disorders: disruptive disorders (DD-attention deficit disorders, oppositional defiant disorder, conduct disorder); adjustment disorders (ADJ); emotional disorders (E...

journal_title：Statistics in medicine

authors： Gibbons RD,Lavigne JV

更新日期：1998-11-15 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：:In epidemiological studies we often want to learn about the direct effect of an exposure on an outcome, i.e. the effect that is not relayed by a specific intermediate variable. In the literature, there are two common definitions of direct effects; controlled and natural. When the intermediate variable and the outcome ...

journal_title：Statistics in medicine

authors： Sjölander A

更新日期：2009-02-15 00:00:00

abstract：:We present a model for describing correlated binocular data from reader-based diagnostic studies, where the same group of readers evaluates the presence or absence of certain diseases on binocular organs (e.g., fellow eyes) of patients. Multiple random effects are incorporated to meaningfully delineate various associa...

journal_title：Statistics in medicine

authors： Withanage N,de Leon AR,Rudnisky CJ

更新日期：2015-12-20 00:00:00

abstract：:This work is motivated by a longitudinal study of women and their ectopic pregnancy outcomes in Lund, Sweden. In this article, we review and apply the Liang-Zeger methodology to the Lund ectopic pregnancy data set. We further analyse the ectopic pregnancy data using conditional modelling approaches suggested by Rosner...

journal_title：Statistics in medicine

authors： Hadgu A,Koch G,Westrom L

更新日期：1997-11-15 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

abstract：:Correlation is inherent in longitudinal studies due to the repeated measurements on subjects, as well as due to time-dependent covariates in the study. In the National Longitudinal Study of Adolescent to Adult Health (Add Health), data were repeatedly collected on children in grades 7-12 across four waves. Thus, obser...

journal_title：Statistics in medicine

authors： Irimata KM,Broatch J,Wilson JR

更新日期：2019-05-30 00:00:00

abstract：:Flexible survival models are in need when modelling data from long term follow-up studies. In many cases, the assumption of proportionality imposed by a Cox model will not be valid. Instead, a model that can identify time varying effects of fixed covariates can be used. Although there are several approaches that deal ...

journal_title：Statistics in medicine

authors： Perperoglou A

更新日期：2016-12-10 00:00:00

abstract：:In repeated measures settings, modeling the correlation pattern of the data can be immensely important for proper analyses. Accurate inference requires proper choice of the correlation model. Optimal efficiency of the estimation procedure demands a parsimonious parameterization of the correlation structure, with suffi...

journal_title：Statistics in medicine

authors： Simpson SL,Edwards LJ,Muller KE,Sen PK,Styner MA

更新日期：2010-07-30 00:00:00

abstract：:Randomized clinical trial designs commonly include one or more planned interim analyses. At these times an external monitoring committee reviews the accumulated data and determines whether it is scientifically and ethically appropriate for the study to continue. With failure-time endpoints, it is common to schedule an...

journal_title：Statistics in medicine

authors： Bagiella E,Heitjan DF

更新日期：2001-07-30 00:00:00

abstract：:Population dynamic models, commonly used tools in the study of epidemics and other complex population processes, are implicit non-linear mathematical equations. Inference based on such models can be difficult due to the problems associated with high dimensional parameters that may be non-identified and complex likelih...

journal_title：Statistics in medicine

authors： Brookhart MA,Hubbard AE,van der Laan MJ,Colford JM Jr,Eisenberg JN

更新日期：2002-12-15 00:00:00

abstract：:Austin Bradford Hill was once a friend to The Lancet, but, as occasionally happens, friends fall out. The great legacy of his association with the journal, however, was Principles of Medical Statistics. As each edition was succeeded by another--the first in 1937, the last in 1991--he seemed to shift his view about the...

journal_title：Statistics in medicine

authors： Horton R

更新日期：2000-12-15 00:00:00

abstract：:A stochastic approximation EM algorithm (SAEM) is described for exploratory factor analysis of dichotomous or ordinal variables. The factor structure is obtained from sufficient statistics that are updated during iterations with the Robbins-Monro procedure. Two large-scale simulations are reported that compare accurac...

journal_title：Statistics in medicine

authors： Camilli G,Geis E

更新日期：2019-09-20 00:00:00

abstract：:The one-step (Peto) method for obtaining pooled effect estimates can yield extremely biased results when applied to unbalanced data. Even for balanced studies, the one-step estimate may incorporate an unacceptable degree of bias. In place of the one-step estimate, we recommend use of ordinary Mantel-Haenszel, weighted...

journal_title：Statistics in medicine

authors： Greenland S,Salvan A

更新日期：1990-03-01 00:00:00

abstract：:Incomplete and unbalanced multivariate data often arise in longitudinal studies due to missing or unequally-timed repeated measurements and/or the presence of time-varying covariates. A general approach to analysing such data is through maximum likelihood analysis using a linear model for the expected responses, and s...

journal_title：Statistics in medicine

authors： Schluchter MD

更新日期：1988-01-01 00:00:00

abstract：:Observational cohort studies often feature longitudinal data subject to irregular observation. Moreover, the timings of observations may be associated with the underlying disease process and must thus be accounted for when analysing the data. This paper suggests that multiple outputation, which consists of repeatedly ...

journal_title：Statistics in medicine

authors： Pullenayegum EM

更新日期：2016-05-20 00:00:00

abstract：:Quality of life (QOL) assessment is a key component of many clinical studies and frequently requires the use of single global summary measures that capture the overall balance of findings from a potentially wide-ranging assessment of QOL issues. We propose and evaluate an irregular multilevel latent variable model sui...

journal_title：Statistics in medicine

authors： Kifley A,Heller GZ,Beath KJ,Bulger D,Ma J,Gebski V

更新日期：2012-05-20 00:00:00

abstract：:We examine the properties of several tests for goodness-of-fit for multinomial logistic regression. One test is based on a strategy of sorting the observations according to the complement of the estimated probability for the reference outcome category and then grouping the subjects into g equal-sized groups. A g x c c...

journal_title：Statistics in medicine

authors： Fagerland MW,Hosmer DW,Bofin AM

更新日期：2008-09-20 00:00:00

abstract：:Meta-analyses of data from epidemiological studies are often based on odds ratios (ORs) or relative risks (RRs) and their 95 per cent confidence intervals (CIs) as reported by the authors. Where possible ORs, RRs and CIs should be checked against the source data. Some simple methods are presented for checking the vali...

journal_title：Statistics in medicine

authors： Lee PN

更新日期：1999-08-15 00:00:00

abstract：:Case-control studies are usually defined to investigate risk factors for a single disease of interest. However, subsequent to data collection, investigators may wish to examine as an 'outcome' a variable that was an exposure in the original study. A naive analysis that disregards the sampling strategy that gave rise t...

journal_title：Statistics in medicine

authors： Reilly M,Torrång A,Klint A

更新日期：2005-12-30 00:00:00

abstract：:We discuss a sample size calculation for a pair-matched case-control study to test for interaction between a specific exposure and a second risk factor. The second risk factor could be either binary or continuous. An algorithm for the calculation of sample size is suggested which is based on a logistic regression mode...

journal_title：Statistics in medicine

authors： Qiu P,Moeschberger ML,Cooke GE,Goldschmidt-Clermont PJ

更新日期：2000-04-15 00:00:00

abstract：:Antimicrobial resistance has become one of the main public health burdens of the last decades, and monitoring the development and spread of non-wild-type isolates has therefore gained increased interest. Monitoring is performed based on the minimum inhibitory concentration (MIC) values, which are collected through the...

journal_title：Statistics in medicine

authors： Jaspers S,Aerts M,Verbeke G,Beloeil PA

更新日期：2014-01-30 00:00:00