A joint modeling approach to data with informative cluster size: robustness to the cluster size model.

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：:Determination of the equation that relates an ordered dependent variable to ordered independent variables is sought. One solution, non-parametric discriminant analysis (NPD), involves obtaining the best monotonic step function by means of a computer search procedure. Although one can use alternative selection criteria...

journal_title：Statistics in medicine

authors： Johnston B,Seshia SS

更新日期：1992-06-15 00:00:00

abstract：:When the event time of interest depends on the censoring time, conventional two-sample test methods, such as the log-rank and Wilcoxon tests, can produce an invalid test result. We extend our previous work on estimation using auxiliary variables to adjust for dependent censoring via multiple imputation, to the compari...

journal_title：Statistics in medicine

authors： Hsu CH,Taylor JM

更新日期：2009-02-01 00:00:00

abstract：:When the accrual rate is low and the treatment period is long, a long observational period is required before information concerning the primary end point, such as binary response, becomes available in the study. Simon's two-stage designs are often employed in Phase II clinical trials to avoid giving patient an ineffe...

journal_title：Statistics in medicine

authors： Chi Y,Chen CM

更新日期：2008-12-20 00:00:00

abstract：:In a cluster randomized cross-over trial, all participating clusters receive both intervention and control treatments consecutively, in separate time periods. Patients recruited by each cluster within the same time period receive the same intervention, and randomization determines order of treatment within a cluster. ...

journal_title：Statistics in medicine

authors： Turner RM,White IR,Croudace T,PIP Study Group.

更新日期：2007-01-30 00:00:00

abstract：:Clinical trials often assess efficacy by comparing treatments on the basis of two or more event-time outcomes. In the case of cancer clinical trials, progression-free survival (PFS), which is the minimum of the time from randomization to progression or to death, summarizes the comparison of treatments on the hazards f...

journal_title：Statistics in medicine

authors： Finkelstein DM,Schoenfeld DA

更新日期：2014-05-30 00:00:00

abstract：:The intraclass correlation coefficient rho plays a key role in the design of cluster randomized trials. Estimates of rho obtained from previous cluster trials and used to inform sample size calculation in planned trials may be imprecise due to the typically small numbers of clusters in such studies. It may be useful t...

journal_title：Statistics in medicine

authors： Ukoumunne OC,Davison AC,Gulliford MC,Chinn S

更新日期：2003-12-30 00:00:00

abstract：:Quantifying socioeconomic disparities and understanding the roots of inequalities are growing topics in cancer research. However, socioeconomic differences are challenging to investigate mainly due to the lack of accurate data at individual-level, while aggregate indicators are only partially informative. We implement...

journal_title：Statistics in medicine

authors： Mezzetti M,Palli D,Dominici F

更新日期：2020-01-15 00:00:00

abstract：:In a phase I clinical trial in cancer patients, the drug involved had one known main adverse effect, which also occurs spontaneously in cancer patients with a fairly high frequency. Experiments in rats have shown marked effects of the drug on tumour growth in high doses, but also dose-dependent toxicity. Consequently,...

journal_title：Statistics in medicine

authors： Møller S

更新日期：1995-05-15 00:00:00

abstract：:We construct nonparametric regression estimators of a number of temporal functions in a multistate system based on a continuous univariate baseline covariate. These estimators include state occupation probabilities, state entry, exit, and waiting (sojourn) time distribution functions of a general progressive (e.g., ac...

journal_title：Statistics in medicine

authors： Mostajabi F,Datta S

更新日期：2013-07-30 00:00:00

abstract：:We consider a general model for anomaly detection in a longitudinal cohort mortality pattern based on logistic joinpoint regression with unknown joinpoints. We discuss backward and forward sequential procedures for selecting both the locations and the number of joinpoints. Estimation of the model parameters and the se...

journal_title：Statistics in medicine

authors： Czajkowski M,Gill R,Rempala G

更新日期：2008-04-30 00:00:00

abstract：:We consider a latent variable hazard model for clustered survival data where clusters are a random sample from an underlying population. We allow interactions between the random cluster effect and covariates. We use a maximum pseudo-likelihood estimator to estimate the mean hazard ratio parameters. We propose a bootst...

journal_title：Statistics in medicine

authors： Cai J,Zhou H,Davis CE

更新日期：1997-09-15 00:00:00

abstract：:Many reactions in enzymology are governed by the Michaelis-Menten equation. Characterising these reactions requires the estimation of the parameters K(M) and V(max) which determine the Michaelis-Menten equation and this is done by observing rates of reactions at a set of substrate concentrations. The choice of substra...

journal_title：Statistics in medicine

authors： Matthews JN,Allcock GC

更新日期：2004-02-15 00:00:00

abstract：:The focus of this paper is dietary intervention trials. We explore the statistical issues involved when the response variable, intake of a food or nutrient, is based on self-report data that are subject to inherent measurement error. There has been little work on handling error in this context. A particular feature of...

journal_title：Statistics in medicine

authors： Keogh RH,Carroll RJ,Tooze JA,Kirkpatrick SI,Freedman LS

更新日期：2016-11-10 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：:Longitudinal studies collect information on a sample of individuals which is followed over time to analyze the effects of individual and time-dependent characteristics on the observed response. These studies often suffer from attrition: individuals drop out of the study before its completion time and thus present inco...

journal_title：Statistics in medicine

authors： Alfò M,Maruotti A

更新日期：2009-08-30 00:00:00

abstract：:We consider the problem of comparing cumulative incidence functions of non-mortality events in the presence of informative coarsening and the competing risk of death. We extend frequentist-based hypothesis tests previously developed for non-informative coarsening and propose a novel Bayesian method based on comparing ...

journal_title：Statistics in medicine

authors： Shardell M,Scharfstein DO,Vlahov D,Galai N

更新日期：2008-12-10 00:00:00

abstract：:Interval-censored survival data often occur in medical studies, especially in clinical trials. In this case, many authors have considered estimation of a survival function. There is, however, relatively little discussion on estimating the variance of estimated survival functions. For right-censored data, a special cas...

journal_title：Statistics in medicine

authors： Sun J

更新日期：2001-04-30 00:00:00

abstract：:The analysis of repeated measures data can be conducted efficiently using a two-level random coefficients model. A standard assumption is that the within-individual (level 1) residuals are uncorrelated. In some cases, especially where measurements are made close together in time, this may not be reasonable and this ad...

journal_title：Statistics in medicine

authors： Goldstein H,Healy MJ,Rasbash J

更新日期：1994-08-30 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：:Appropriate quantification of added usefulness offered by new markers included in risk prediction algorithms is a problem of active research and debate. Standard methods, including statistical significance and c statistic are useful but not sufficient. Net reclassification improvement (NRI) offers a simple intuitive w...

journal_title：Statistics in medicine

authors： Pencina MJ,D'Agostino RB Sr,Steyerberg EW

更新日期：2011-01-15 00:00:00

abstract：:Several relative risk models for survival time data in drug combination therapy are derived and their properties are discussed. The main intention of this paper is to clarify the differences among the models in order to help to choose the appropriate one in a given situation. The models are motivated by discussing the...

journal_title：Statistics in medicine

authors： Kübler J,Schumacher M

更新日期：1990-12-01 00:00:00

abstract：:Ewell and Ibrahim derived the large sample distribution of the logrank statistic under general local alternatives. Their asymptotic results enable us to extend several group sequential designs which allow for early stopping in favour of the null hypothesis to the setting in which the cure rate model is appropriate. In...

journal_title：Statistics in medicine

authors： Patricia Bernardo MV,Ibrahim JG

更新日期：2000-11-30 00:00:00

abstract：:Phase II studies in oncology are frequently conducted as two-stage single-arm trials with a binary endpoint indicating tumor response. As a common feature of these designs, the sample sizes of the two stages and the decision rules for the interim and the final analysis have to be pre-specified and adhered to strictly ...

journal_title：Statistics in medicine

authors： Englert S,Kieser M

更新日期：2015-06-15 00:00:00

abstract：:Several large-sample confidence intervals for the ratio of independent binomial proportions are compared in terms of exact coverage probability and width. A non-iterative approximate Bayesian interval is derived and its frequency properties are superior to all of the non-iterative confidence intervals considered. The ...

journal_title：Statistics in medicine

authors： Price RM,Bonett DG

更新日期：2008-11-20 00:00:00

abstract：:Multilevel mixed effects survival models are used in the analysis of clustered survival data, such as repeated events, multicenter clinical trials, and individual participant data (IPD) meta-analyses, to investigate heterogeneity in baseline risk and covariate effects. In this paper, we extend parametric frailty model...

journal_title：Statistics in medicine

authors： Crowther MJ,Look MP,Riley RD

更新日期：2014-09-28 00:00:00

abstract：:Kappa coefficients are measures of correlation between categorical variables often used as reliability or validity coefficients. We recapitulate development and definitions of the K (categories) by M (ratings) kappas (K x M), discuss what they are well- or ill-designed to do, and summarize where kappas now stand with ...

journal_title：Statistics in medicine

authors： Chmura Kraemer H,Periyakoil VS,Noda A

更新日期：2002-07-30 00:00:00

abstract：:Growth trends in children are often based on cross-sectional studies, in which a sample of the population is investigated at one given point in time. Estimating age-related percentiles in such studies involves fitting data distributions, each of which is specific for one age group, and a subsequent smoothing of the pe...

journal_title：Statistics in medicine

authors： Sorribas A,March J,Voit EO

更新日期：2000-03-15 00:00:00

abstract：:When a cancer patient develops a new tumor it is necessary to determine if it is a recurrence (metastasis) of the original cancer, or an entirely new occurrence of the disease. This is accomplished by assessing the histo-pathology of the lesions. However, there are many clinical scenarios in which this pathological di...

journal_title：Statistics in medicine

authors： Ostrovnaya I,Olshen AB,Seshan VE,Orlow I,Albertson DG,Begg CB

更新日期：2010-07-10 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