Multilevel time series models with applications to repeated measures data.

abstract：:Studies based on aggregated hospital outcome data have established that there is a relationship between nurse staffing and adverse events. However, this result could not be confirmed in Belgium where 96 per cent of the variability of nurse staffing levels over nursing units (belonging to different hospitals) is explai...

journal_title：Statistics in medicine

authors： Diya L,Lesaffre E,Van den Heede K,Sermeus W,Vleugels A

更新日期：2010-03-30 00:00:00

abstract：:Logistic regression analysis may well be used to develop a prognostic model for a dichotomous outcome. Especially when limited data are available, it is difficult to determine an appropriate selection of covariables for inclusion in such models. Also, predictions may be improved by applying some sort of shrinkage in t...

journal_title：Statistics in medicine

authors： Steyerberg EW,Eijkemans MJ,Harrell FE Jr,Habbema JD

更新日期：2000-04-30 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 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

abstract：:Population heterogeneity is frequently observed among patients' treatment responses in clinical trials because of various factors such as clinical background, environmental, and genetic factors. Different subpopulations defined by those baseline factors can lead to differences in the benefit or safety profile of a the...

journal_title：Statistics in medicine

authors： Chiu YD,Koenig F,Posch M,Jaki T

更新日期：2018-12-20 00:00:00

abstract：:The analysis and recognition of disease clustering in space and its representation on a map is an important problem in epidemiology. An approach using mixture models to identify spatial heterogeneity in disease risk and map construction within an empirical Bayes framework is described. Once heterogeneity is detected, ...

journal_title：Statistics in medicine

authors： Schlattmann P,Dietz E,Böhning D

更新日期：1996-04-15 00:00:00

abstract：:In this paper, we define a modified version τ(b) of Kendall's tau to measure the association in a pair (X,Y) of random variables subject to fixed left censoring due to known lower detection limits. We provide a nonparametric estimator of τ(b) and investigate its asymptotic properties. We then assume an Archimedean cop...

journal_title：Statistics in medicine

authors： Romdhani H,Lakhal-Chaieb L

更新日期：2011-11-20 00:00:00

abstract：:The analysis of patient-reported outcomes or other psychological traits can be realized using the Rasch measurement model. When the objective of a study is to compare groups of individuals, it is important, before the study, to define a sample size such that the group comparison test will attain a given power. The Ras...

journal_title：Statistics in medicine

authors： Hardouin JB,Blanchin M,Feddag ML,Le Néel T,Perrot B,Sébille V

更新日期：2015-07-20 00:00:00

abstract：:We propose a new design for dose finding for cytotoxic agents in two ordered groups of patients. By ordered groups, we mean that prior to the study there is clinical information that would indicate that for a given dose one group would be more susceptible to toxicities than patients in the other group. The designs are...

journal_title：Statistics in medicine

authors： Conaway MR,Wages NA

更新日期：2017-01-30 00:00:00

abstract：:Graphical methods based on the analysis of differences between log cumulative hazard functions are considered for a two-group semi-proportional hazard model which allows for interaction between treatments and covariates. Confidence procedures and test statistics that can be used to test for interaction and for main ef...

journal_title：Statistics in medicine

authors： Dabrowska DM,Doksum KA,Feduska NJ,Husing R,Neville P

更新日期：1992-08-01 00:00:00

abstract：:Proportional hazards (or Cox) regression is a popular method for modelling the effects of prognostic factors on survival. Use of cubic spline functions to model time-by-covariate interactions in Cox regression allows investigation of the shape of a possible covariate-time dependence without having to specify a specifi...

journal_title：Statistics in medicine

authors： Hess KR

更新日期：1994-05-30 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：:When investigating health disparities, it can be of interest to explore whether adjustment for socioeconomic factors at the neighborhood level can account for, or even reverse, an unadjusted difference. Recently, we proposed new methods to adjust the effect of an individual-level covariate for confounding by unmeasure...

journal_title：Statistics in medicine

authors： Brumback BA,Zheng HW,Dailey AB

更新日期：2013-04-15 00:00:00

abstract：:Risk prediction models play an important role in prevention and treatment of several diseases. Models that are in clinical use are often refined and improved. In many instances, the most efficient way to improve a successful model is to identify subgroups for which there is a specific biological rationale for improvem...

journal_title：Statistics in medicine

authors： Biswas S,Arun B,Parmigiani G

更新日期：2014-05-20 00:00:00

abstract：:Many split-mouth trials are characterized by the pairing of site-specific outcome and baseline data within each segment of a subject's mouth. However when the response variable of interest is binary, methods of statistical analysis for this design are not well developed. In this paper we present several analytic appro...

journal_title：Statistics in medicine

authors： Donner A,Zou GY

更新日期：2007-08-15 00:00:00

abstract：:In the development of a new treatment in oncology, phase II trials play a key role. On the basis of the data obtained during phase II, it is decided whether the treatment should be studied further. Therefore, the decision to be made on the basis of the data of a phase II trial must be as accurate as possible. For ethi...

journal_title：Statistics in medicine

authors： Kunz CU,Kieser M

更新日期：2012-12-30 00:00:00

abstract：:Existing methods for power analysis for longitudinal study designs are limited in that they do not adequately address random missing data patterns. Although the pattern of missing data can be assessed during data analysis, it is unknown during the design phase of a study. The random nature of the missing data pattern ...

journal_title：Statistics in medicine

authors： Tu XM,Zhang J,Kowalski J,Shults J,Feng C,Sun W,Tang W

更新日期：2007-07-10 00:00:00

abstract：:We consider methods for selecting the joint specification of the mean and variance functions in statistical models for rates or counts. Based on analyses of diagnosis-specific hospital discharge rates in Michigan, we show that a Poisson model with an extra variance component for the systematic variation is superior to...

journal_title：Statistics in medicine

authors： Wolfe RA,Petroni GR,McLaughlin CG,McMahon LF Jr

更新日期：1991-09-01 00:00:00

abstract：:In order for national statistical offices to maintain the trust of the public to collect data and publish statistics of importance to society and decision-making, it is imperative that respondents (persons or establishments) be guaranteed privacy and confidentiality in return for providing requested confidential data....

journal_title：Statistics in medicine

authors： Gonzalez JF Jr,Cox LH

更新日期：2005-02-28 00:00:00

abstract：:For many HIV-infected patients, use of antiretroviral therapy (ART) results in a sustained suppression of plasma viral load to undetectable levels. However, due to lack of antigenic stimulation, this may also result in a gradual loss of cell-mediated immune (CMI) responses that help control HIV infection. In concept, ...

journal_title：Statistics in medicine

authors： Mogg R,Mehrotra DV

更新日期：2007-02-10 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：:We analyse the effect of using prevalence rates based on populations with different sizes in the power of spatial independence tests. We compare the well known spatial correlation Moran's index to three indexes obtained after adjusting for population density, one proposed by Oden, another proposed by Waldhör, and a th...

journal_title：Statistics in medicine

authors： Assunção RM,Reis EA

更新日期：1999-08-30 00:00:00

abstract：:Proportional odds regression models for multinomial probabilities based on ordered categories have been generalized in two somewhat different directions. Models having scale as well as location parameters for adjustment of boundaries (on an unobservable, underlying continuum) between categories have been employed in t...

journal_title：Statistics in medicine

authors： Cox C

更新日期：1995-06-15 00:00:00

abstract：:Age-period-cohort (APC) analysis is widely used in cancer epidemiology to model trends in cancer rates. We develop methods for comparative APC analysis of two independent cause-specific hazard rates assuming that an APC model holds for each one. We construct linear hypothesis tests to determine whether the two hazards...

journal_title：Statistics in medicine

authors： Rosenberg PS,Anderson WF

更新日期：2010-05-20 00:00:00

abstract：:We survey models for analysing repeated observations on an ordered categorical response variable. The models presented are univariate models that permit correlation among repeated measurements. The models describe simultaneously the dependence of marginal response distributions on values of explanatory variables and o...

journal_title：Statistics in medicine

authors： Agresti A

更新日期：1989-10-01 00:00:00

abstract：:In this paper, we argue that causal effect models for realistic individualized treatment rules represent an attractive tool for analyzing sequentially randomized trials. Unlike a number of methods proposed previously, this approach does not rely on the assumption that intermediate outcomes are discrete or that models ...

journal_title：Statistics in medicine

authors： Bembom O,van der Laan MJ

更新日期：2008-08-30 00:00:00

abstract：:A method is presented which allows us to adapt the sample size as well as the number and time points of interim analyses to the treatment difference observed at an interim look during the course of a clinical trial with censored survival time as the endpoint. The method allows the inclusion of data inspections during ...

journal_title：Statistics in medicine

authors： Schäfer H,Müller HH

更新日期：2001-12-30 00:00:00

abstract：:Instrumental variable is an essential tool for addressing unmeasured confounding in observational studies. Two-stage predictor substitution (2SPS) estimator and two-stage residual inclusion (2SRI) are two commonly used approaches in applying instrumental variables. Recently, 2SPS was studied under the additive hazards...

journal_title：Statistics in medicine

authors： Ying A,Xu R,Murphy J

更新日期：2019-05-10 00:00:00

abstract：:For genome-wide association studies, we propose a new method for identifying significant biological pathways. In this approach, we aggregate data across single-nucleotide polymorphisms to obtain summary measures at the gene level. We then use a hierarchical Bayesian model, which takes the gene-level summary measures a...

journal_title：Statistics in medicine

authors： Shahbaba B,Shachaf CM,Yu Z

更新日期：2012-05-10 00:00:00

abstract：:The relative importance of prognostic factors in regression can be measured either by standardized regression coefficients or by percentages of explained variation in a dependent variable. One advantage of using explained variation is the direct comparability of qualitative prognostic factors with others, or of groups...

journal_title：Statistics in medicine

authors： Schemper M

更新日期：1993-12-30 00:00:00