A test of inflated zeros for Poisson regression models.

abstract：:Many statistical studies report p-values for inferential purposes. In several scenarios, the stochastic aspect of p-values is neglected, which may contribute to drawing wrong conclusions in real data experiments. The stochastic nature of p-values makes their use to examine the performance of given testing procedures o...

journal_title：Statistical methods in medical research

authors： Vexler A,Yu J,Zhao Y,Hutson AD,Gurevich G

更新日期：2018-12-01 00:00:00

abstract：:This study proposes semiparametric models for analysis of hierarchical count data containing excess zeros and overdispersion simultaneously. The methods discussed in this paper handle nonlinear covariate effects through flexible semiparametric multilevel regression techniques. This is performed by providing a comprehe...

journal_title：Statistical methods in medical research

authors： Mahmoodi M,Moghimbeigi A,Mohammad K,Faradmal J

更新日期：2018-04-01 00:00:00

abstract：:Rapid Early Action for Coronary Treatment (REACT) was a multisite trial testing a community intervention to reduce the delay between onset of symptoms of acute myocardial infarction (MI) and patients' arrival at a hospital emergency department. The study employed a group-randomized trial design, with ten communities r...

journal_title：Statistical methods in medical research

authors： Murray DM,Feldman HA,McGovern PG

更新日期：2000-04-01 00:00:00

abstract：:Simple mechanistic epidemic models are widely used for forecasting and parameter estimation of infectious diseases based on noisy case reporting data. Despite the widespread application of models to emerging infectious diseases, we know little about the comparative performance of standard computational-statistical fra...

journal_title：Statistical methods in medical research

authors： Li M,Dushoff J,Bolker BM

更新日期：2018-07-01 00:00:00

abstract：:We consider two exact unconditional procedures to test the difference between two multinomials with ordered categorical data. Exact unconditional procedures are compared to other approaches based on the Wilcoxon mid-rank test and the proportional odds model. We use a real example from an arthritis pain study to illust...

journal_title：Statistical methods in medical research

authors： Shan G,Ma C

更新日期：2016-02-01 00:00:00

abstract：:Statistical methods for spatial health data to identify the significant covariates associated with the health outcomes are of critical importance. Most studies have developed variable selection approaches in which the covariates included appear within the spatial domain and their effects are fixed across space. Howeve...

journal_title：Statistical methods in medical research

authors： Choi J,Lawson AB

更新日期：2018-01-01 00:00:00

abstract：:Competing risks data often exist within a center in multi-center randomized clinical trials where the treatment effects or baseline risks may vary among centers. In this paper, we propose a subdistribution hazard regression model with multivariate frailty to investigate heterogeneity in treatment effects among centers...

journal_title：Statistical methods in medical research

authors： Ha ID,Christian NJ,Jeong JH,Park J,Lee Y

更新日期：2016-12-01 00:00:00

abstract：:Covariate-adaptive designs are widely used to balance covariates and maintain randomization in clinical trials. Adaptive designs for discrete covariates and their asymptotic properties have been well studied in the literature. However, important continuous covariates are often involved in clinical studies. Simply disc...

journal_title：Statistical methods in medical research

authors： Li X,Zhou J,Hu F

更新日期：2019-06-01 00:00:00

abstract：:In this paper age-space-time models based on one and two-dimensional P-splines with B-spline bases are proposed for smoothing mortality rates, where both fixed relative scale and scale invariant two-dimensional penalties are examined. Model fitting and inference are carried out using integrated nested Laplace approxim...

journal_title：Statistical methods in medical research

authors： Goicoa T,Adin A,Etxeberria J,Militino AF,Ugarte MD

更新日期：2019-02-01 00:00:00

abstract：:Nonlinear mixed-effects modeling is one of the most popular tools for analyzing repeated measurement data, particularly for applications in the biomedical fields. Multiple integration and nonlinear optimization are the two major challenges for likelihood-based methods in nonlinear mixed-effects modeling. To solve thes...

journal_title：Statistical methods in medical research

authors： Yuan M,Zhu Z,Yang Y,Zhao M,Sasser K,Hamadeh H,Pinheiro J,Xu XS

更新日期：2020-08-24 00:00:00

abstract：:Most statistical developments in the joint modelling area have focused on the shared random-effect models that include characteristics of the longitudinal marker as predictors in the model for the time-to-event. A less well-known approach is the joint latent class model which consists in assuming that a latent class s...

journal_title：Statistical methods in medical research

authors： Proust-Lima C,Séne M,Taylor JM,Jacqmin-Gadda H

更新日期：2014-02-01 00:00:00

abstract：:A growing body of evidence suggests that genetic factors have an important influence on the onset and course of smoking. Here we review some of the statistical methods that have been used to test for genetic influences on smoking behaviour, with a particular focus on studies of large national twin samples. We show how...

journal_title：Statistical methods in medical research

authors： Heath AC,Madden PA,Martin NG

更新日期：1998-06-01 00:00:00

abstract：:Conditional two-part random-effects models have been proposed for the analysis of healthcare cost panel data that contain both zero costs from the non-users of healthcare facilities and positive costs from the users. These models have been extended to accommodate more flexible data structures when using the generalize...

journal_title：Statistical methods in medical research

authors： Zhang B,Liu W,Hu Y

更新日期：2018-10-01 00:00:00

abstract：:Accelerated failure time model is a popular model to analyze censored time-to-event data. Analysis of this model without assuming any parametric distribution for the model error is challenging, and the model complexity is enhanced in the presence of large number of covariates. We developed a nonparametric Bayesian met...

journal_title：Statistical methods in medical research

authors： Zhang Z,Sinha S,Maiti T,Shipp E

更新日期：2018-04-01 00:00:00

abstract：:Appropriate handling of aggregate missing outcome data is necessary to minimise bias in the conclusions of systematic reviews. The two-stage pattern-mixture model has been already proposed to address aggregate missing continuous outcome data. While this approach is more proper compared with the exclusion of missing co...

journal_title：Statistical methods in medical research

authors： Spineli LM,Kalyvas C,Papadimitropoulou K

更新日期：2021-01-06 00:00:00

abstract：:Studies of HIV dynamics in AIDS research are very important for understanding pathogenesis of HIV infection and for assessing the potency of antiviral therapies. Since the viral dynamic results from clinical data were first published by Ho et al. and Wei et al., the study of HIV-1 dynamics in vivo has drawn a great at...

journal_title：Statistical methods in medical research

authors： Wu H

更新日期：2005-04-01 00:00:00

abstract：:Sensitive questions are often involved in healthcare or medical survey research. Much empirical evidence has shown that the randomized response technique is useful for the collection of truthful responses. However, few studies have discussed methods to estimate the dependence of sensitive responses of multiple types. ...

journal_title：Statistical methods in medical research

authors： Chu AM,So MK,Chan TW,Tiwari A

更新日期：2020-03-01 00:00:00

abstract：:Previous work has shown that individual randomized "proof-of-concept" (PoC) studies may be designed to maximize cost-effectiveness, subject to an overall PoC budget constraint. Maximizing cost-effectiveness has also been considered for arrays of simultaneously executed PoC studies. Defining Type III error as the oppor...

journal_title：Statistical methods in medical research

authors： He L,Du L,Antonijevic Z,Posch M,Korostyshevskiy VR,Beckman RA

更新日期：2020-09-21 00:00:00

abstract：:In this paper, a new allocation rule for treatment assignments in sequential clinical trials is proposed. The stratified and randomized play-the-winner rule (SRPWR) is an extension of the randomized play-the-winner rule to more than two treatments. It is applicable to cases where the probabilities of success of a trea...

journal_title：Statistical methods in medical research

authors： Liang Y,Carriere KC

更新日期：2008-12-01 00:00:00

abstract：:We review recent work on the application of pseudo-observations in survival and event history analysis. This includes regression models for parameters like the survival function in a single point, the restricted mean survival time and transition or state occupation probabilities in multi-state models, e.g. the competi...

journal_title：Statistical methods in medical research

authors： Andersen PK,Perme MP

更新日期：2010-02-01 00:00:00

abstract：:Cluster randomized and multicentre trials evaluate the effect of a treatment on persons nested within clusters, for instance patients within clinics or pupils within schools. Although equal sample sizes per cluster are generally optimal for parameter estimation, they are rarely feasible. This paper addresses the relat...

journal_title：Statistical methods in medical research

authors： van Breukelen GJ,Candel MJ,Berger MP

更新日期：2008-08-01 00:00:00

abstract：:Agreement between two methods of clinical measurement can be quantified using the differences between observations made using the two methods on the same subjects. The 95% limits of agreement, estimated by mean difference +/- 1.96 standard deviation of the differences, provide an interval within which 95% of differenc...

journal_title：Statistical methods in medical research

authors： Bland JM,Altman DG

更新日期：1999-06-01 00:00:00

abstract：:In many health studies, researchers are interested in estimating the treatment effects on the outcome around and through an intermediate variable. Such causal mediation analyses aim to understand the mechanisms that explain the treatment effect. Although multiple mediators are often involved in real studies, most of t...

journal_title：Statistical methods in medical research

authors： Taguri M,Featherstone J,Cheng J

更新日期：2018-01-01 00:00:00

abstract：:This article outlines the statistical developments that have taken place in the use of the EM algorithm in emission and transmission tomography during the past decade or so. We discuss the statistical aspects of the modelling of the projection data for both the emission and transmission cases and define the relevant p...

journal_title：Statistical methods in medical research

authors： Kay J

更新日期：1997-03-01 00:00:00

abstract：:The probability model for periodic screening was extended to provide statistical inference for sensitivity depending on sojourn time, in which the sensitivity was modeled as a function of time spent in the preclinical state and the sojourn time. The likelihood function with the proposed sensitivity model was then eval...

journal_title：Statistical methods in medical research

authors： Kim S,Wu D

更新日期：2016-04-01 00:00:00

abstract：:In recent years, disease mapping studies have become a routine application within geographical epidemiology and are typically analysed within a Bayesian hierarchical model formulation. A variety of model formulations for the latent level have been proposed but all come with inherent issues. In the classical BYM (Besag...

journal_title：Statistical methods in medical research

authors： Riebler A,Sørbye SH,Simpson D,Rue H

更新日期：2016-08-01 00:00:00

abstract：:We propose a cross-validated area under the receiving operator characteristic (ROC) curve (CV-AUC) criterion for tuning parameter selection for penalized methods in sparse, high-dimensional logistic regression models. We use this criterion in combination with the minimax concave penalty (MCP) method for variable selec...

journal_title：Statistical methods in medical research

authors： Jiang D,Huang J,Zhang Y

更新日期：2013-10-01 00:00:00

abstract：:In multi-regional trials, the underlying overall and region-specific accrual rates often do not hold constant over time and different regions could have different start-up times, which combined with initial jump in accrual within each region often leads to a discontinuous overall accrual rate, and these issues associa...

journal_title：Statistical methods in medical research

authors： Deng Y,Zhang X,Long Q

更新日期：2017-04-01 00:00:00

abstract：:It is a common practice to analyze longitudinal data frequently arisen in medical studies using various mixed-effects models in the literature. However, the following issues may standout in longitudinal data analysis: (i) In clinical practice, the profile of each subject's response from a longitudinal study may follow...

journal_title：Statistical methods in medical research

authors： Huang Y,Chen J,Yin P

更新日期：2017-02-01 00:00:00

abstract：:Serial measurements of prostate-specific antigen (PSA) are used as a biomarker for men diagnosed with prostate cancer following an active monitoring programme. Distinguishing pathological changes from natural age-related changes is not straightforward. Here, we compare four approaches to modelling age-related change i...

journal_title：Statistical methods in medical research

authors： Simpkin AJ,Metcalfe C,Martin RM,Lane JA,Donovan JL,Hamdy FC,Neal DE,Tilling K

更新日期：2016-10-01 00:00:00