Inference in functional mixed regression models with applications to Positron Emission Tomography imaging data.

abstract：:Suppose we use generalized estimating equations to estimate a marginal regression model for repeated binary observations. There are no established summary statistics available for assessing the adequacy of the fitted model. In this paper we propose a goodness-of-fit test statistic which has an approximate chi-squared ...

journal_title：Statistics in medicine

authors： Horton NJ,Bebchuk JD,Jones CL,Lipsitz SR,Catalano PJ,Zahner GE,Fitzmaurice GM

更新日期：1999-01-30 00:00:00

abstract：:We explore structural equations with latent variables for modelling between-individual variability and measurement error in the analysis of longitudinal binary and ordinal data. The structural equation formulation provides insight into the assumptions and differences in interpretation of methods that are popular for l...

journal_title：Statistics in medicine

authors： Palta M,Lin CY

更新日期：1999-02-28 00:00:00

abstract：:With discovery of an increasing number of candidate genes that may affect inter-individual variability in response to drugs, the design of drug trials that incorporate their study has become relevant. We discuss the determination of sample size for such studies when the number of tests to perform is given, or, alterna...

journal_title：Statistics in medicine

authors： Elston RC,Idury RM,Cardon LR,Lichter JB

更新日期：1999-03-30 00:00:00

abstract：:When several independent groups have conducted studies to estimate a procedure's success rate, it is often of interest to combine the results of these studies in the hopes of obtaining a better estimate for the true unknown success rate of the procedure. In this paper we present two hierarchical methods for estimating...

journal_title：Statistics in medicine

authors： Zhou XH,Brizendine EJ,Pritz MB

更新日期：1999-03-15 00:00:00

abstract：:Hierarchical linear models are useful for understanding relationships in hierarchical data structures, such as patients within hospitals or physicians within hospitals. In this tutorial we provide an introduction to the technique in general terms, and then specify model notation and assumptions in detail. We describe ...

journal_title：Statistics in medicine

authors： Sullivan LM,Dukes KA,Losina E

更新日期：1999-04-15 00:00:00

abstract：:We propose a Bayesian hierarchical model to estimate age-specific cancer incidence per year from age-specific cancer mortality. The model is based upon the empirical Bayesian approach of Liao and Brookmeyer (1995) and extends that model by consideration of the dependence on age. The incident cases per year are conside...

journal_title：Statistics in medicine

authors： Mezzetti M,Robertson C

更新日期：1999-04-30 00:00:00

abstract：:Many cohort studies and clinical trials have designs which involve repeated measurements of disease markers. One problem in such longitudinal studies, when the primary interest is to estimate and to compare the evolution of a disease marker, is that planned data are not collected because of missing data due to missing...

journal_title：Statistics in medicine

authors： Touloumi G,Pocock SJ,Babiker AG,Darbyshire JH

更新日期：1999-05-30 00:00:00

abstract：:In repeated measures bioavailability/bioequivalence studies involving two formulations, the underlying measurements, such as the area under the plasma concentration-time curve (AUC) and the maximum plasma concentration (Cmax), typically have a block compound-symmetric covariance matrix. To test the equality of the var...

journal_title：Statistics in medicine

authors： Jiang G,Sarkar SK

更新日期：1999-05-15 00:00:00

abstract：:In clinical studies, we often consider not only patients' survival time, but also their quality of life. Quality adjusted life years (QALY) is an integrated measure of medical outcome that combines a patient's quantity and quality of life. Estimation of mean QALY for a group of patients is complicated by the fact that...

journal_title：Statistics in medicine

authors： Shen LZ,Pulkstenis E,Hoseyni M

更新日期：1999-06-30 00:00:00

abstract：:To assess the costs and benefits of screening and treatment strategies, it is important to know what would have happened had there been no intervention. In today's ethical climate, however, it is almost impossible to observe this directly and therefore must be inferred from observations with intervention. In this pape...

journal_title：Statistics in medicine

authors： Craig BA,Fryback DG,Klein R,Klein BE

更新日期：1999-06-15 00:00:00

abstract：:A variety of methods are available for analysing repeated measurements data where the outcome is continuous. However, there is little information on how established methods, such as summary statistics and repeated measures analysis of variance (RMAOV), compare in practice with methods that have become available to app...

journal_title：Statistics in medicine

authors： Omar RZ,Wright EM,Turner RM,Thompson SG

更新日期：1999-07-15 00:00:00

abstract：:In randomized HIV/AIDS clinical trials, CD4 lymphocyte counts and plasma HIV-1 RNA measurements are often used as endpoints. The comparison between treatment groups is mainly based on a summary measure of outcome, so-called summary statistic. Such analyses are often complicated by missing data occurring as drop-outs. ...

journal_title：Statistics in medicine

authors： Le Corfec E,Chevret S,Costagliola D

更新日期：1999-07-30 00:00:00

abstract：:Oral practice examinations (OPEs) are used in many anaesthesiology programmes to familiarize anaesthesiology residents with the format of the oral examination administered by the American Board of Anesthesiology. The OPE outcome (final grade) consists of 'Definite Not Pass', 'Probable Not Pass', 'Probable Pass' and 'D...

journal_title：Statistics in medicine

authors： Tan M,Qu Y,Mascha E,Schubert A

更新日期：1999-08-15 00:00:00

abstract：:Meta-analysis is a popular tool for combining evidence from several related studies. The technique is usually used to combine randomized clinical trials, case-control studies or prospective studies where each study has its own exposed and unexposed groups. By including separate 'study effects' (either fixed or random)...

journal_title：Statistics in medicine

authors： Brumback BA,Holmes LB,Ryan LM

更新日期：1999-08-30 00:00:00

abstract：:This paper reviews the established practice of providing evidence to regulatory authorities about the claimed properties (such as efficacy and safety) of new pharmaceutical products. The established conventions and procedures are contrasted with scientific concepts and principles. The following issues are discussed: (...

journal_title：Statistics in medicine

authors： Longford NT,Nelder JA

更新日期：1999-09-15 00:00:00

abstract：:We propose a likelihood method for estimating parameters in generalized linear models with missing covariates and a non-ignorable missing data mechanism. In this paper, we focus on one missing covariate. We use a logistic model for the probability that the covariate is missing, and allow this probability to depend on ...

journal_title：Statistics in medicine

authors： Lipsitz SR,Ibrahim JG,Chen MH,Peterson H

更新日期：1999-09-15 00:00:00

abstract：:We investigate a resampling method for bias correction in group sequential designs with censored survival data using logrank testing. The method draws nested bootstrap samples of different sizes from the observed data in order to mimic the large sample independent increment property of statistics resulting from sequen...

journal_title：Statistics in medicine

authors： LeBlanc M,Crowley J

更新日期：1999-10-15 00:00:00

abstract：:Many biological processes give outcome data which show a curvilinear association with time which tends to an asymptote. We show how autoregressive models can be used to describe this association within individual subjects. We also present a Bayesian approach implemented using statistical software, BUGS, to fit these m...

journal_title：Statistics in medicine

authors： Mander AP,Hughes MD,Sharp SJ,Lamm CJ

更新日期：1999-10-30 00:00:00

abstract：:In longitudinal studies each subject is observed at several different times. Longitudinal studies are rarely balanced and complete due to occurrence of missing data. Little proposed pattern-mixture models for the analysis of incomplete multivariate normal data. Later, Little proposed an approach to modelling the drop-...

journal_title：Statistics in medicine

authors： Park T,Lee SY

更新日期：1999-11-15 00:00:00

abstract：:In a study of the impact of case management teams in a publicly funded mental health programme, mental health patients were interviewed about a variety of outcomes suggestive of successful community adaptation, such as support from family and friends and avoidance of legal problems. Because outcome data were missing f...

journal_title：Statistics in medicine

authors： Belin TR,Hu MY,Young AS,Grusky O

更新日期：1999-11-30 00:00:00

abstract：:Routine analysis of public health surveillance data to detect departures from historical patterns of disease frequency is required to enable timely public health responses to decrease unnecessary morbidity and mortality. We describe a monitoring system incorporating statistical 'flags' identifying unusually large incr...

journal_title：Statistics in medicine

authors： Williamson GD,Weatherby Hudson G

更新日期：1999-12-15 00:00:00

abstract：:The two-stage design involves sample size recalculation using an interim variance estimate. Stein proposed the design in 1945; biostatisticians recently have shown renewed interest in it. Wittes and Brittain proposed a modification aimed at greater efficiency; Gould and Shih proposed a similar procedure, but with a di...

journal_title：Statistics in medicine

authors： Zucker DM,Wittes JT,Schabenberger O,Brittain E

更新日期：1999-12-30 00:00:00

abstract：:Matching in case-control studies is a situation in which one wishes to make inferences about a parameter of interest in the presence of nuisance parameters. The usual approach is to apply a conditional likelihood. A bivariate latent class log-linear model for binomial responses is shown to yield a standard likelihood ...

journal_title：Statistics in medicine

authors： Lindsey JK

更新日期：2000-01-15 00:00:00

abstract：:Prognostic models can be developed with multiple regression analysis of a data set containing individual patient data. Often this data set is relatively small, while previously published studies present results for larger numbers of patients. We describe a method to combine univariable regression results from the medi...

journal_title：Statistics in medicine

authors： Steyerberg EW,Eijkemans MJ,Van Houwelingen JC,Lee KL,Habbema JD

更新日期：2000-01-30 00:00:00

abstract：:This paper considers the practical problem in animal carcinogenesis experiments where several treatment groups are compared with a control group in a one-way layout and the observed survival data are subject to random right-censorship. Proposed herein are multiple testing procedures based on two-sample weighted logran...

journal_title：Statistics in medicine

authors： Chen YI

更新日期：2000-02-15 00:00:00

abstract：:Stability aspects of recursive partitioning procedures are investigated. Using resampling techniques, diagnostic tools to assess single split stability and overall tree stability are introduced. To correct for the procedure's preference for covariates with many unique realizations, corrected p-values are used in the f...

journal_title：Statistics in medicine

authors： Dannegger F

更新日期：2000-02-29 00:00:00

abstract：:The method of generalized estimating equations has become almost standard for analysing longitudinal and other correlated response data. However, we have found that if binary responses have less than binomial variation over clusters, and are modelled using exchangeable correlations, prevailing software implementations...

journal_title：Statistics in medicine

authors： Hanley JA,Negassa A,Edwardes MD

更新日期：2000-03-15 00:00:00

abstract：:In this paper, the population attributable fraction is studied using the potential responses framework of Rubin's causal model. This framework facilitates definition of a general measure of population attributable effect which can accommodate many-valued and multivariate exposures as well as many-valued responses. Inf...

journal_title：Statistics in medicine

authors： Graham P

更新日期：2000-04-15 00:00:00

abstract：:Standardized mortality ratios (SMRs) have been criticized as lacking validity, and it has been recommended to use standardized rate ratios (SRRs) instead. A review of the epidemiology literature and standard epidemiology textbooks showed disagreement concerning the validity of SMRs and a lack of data to support claims...

journal_title：Statistics in medicine

authors： Goldman DA,Brender JD

更新日期：2000-04-30 00:00:00

abstract：:Often in medical studies, study subjects become a natural block of observations repeated over a time period. Some subjects miss observations, thus becoming incomplete blocks of observations. We are interested in testing an ordered alternative (or time trend), and propose a non-parametric method to detect a trend in in...

journal_title：Statistics in medicine

authors： Park E,Lee YJ

更新日期：2000-05-30 00:00:00