解剖学和形态学
麻醉学
听力与言语-语言病理学
行为科学
心脏和心血管系统
细胞和组织工程学
临床神经病学
危重症监护医学
牙科,口腔外科和医学
皮肤病学
急诊医学
内分泌学和新陈代谢
肠胃学和肝脏学
老人病学和老年医学
卫生保健科学和服务
血液学
免疫学
传染病
综合和补充性医学
医学伦理学
医学信息学
医学实验室技术
医学,全科和内科
医学,法律
医学,研究和试验
神经系统科学
护理
营养学和饮食学
产科医学和妇科医学
肿瘤学
眼科学
整形外科学
耳鼻喉科学
病理学
儿科学
周围血管疾病
药理学和药剂学
生理学
基本医疗保健
精神病学
公共、环境和职业卫生
放射学,核医学和医学成像
康复学
生殖生物学
呼吸系统
风湿病学
运动科学
外科学
毒理学
热带医学
泌尿学和肾脏学
病毒学
老年医学
健康政策和服务
心理学,临床
abstract::Non-tumor cell-based model systems have recently gained interest in pharmacogenetic research as a hypothesis generating tool. The hypotheses generated from these model systems can be followed up in functional studies, or tested in individuals taking the same investigational agents. The current cellular phenotypes (e.g...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3649
更新日期:2009-09-20 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
pub_type: 杂志文章
doi:10.1002/sim.3604
更新日期:2009-08-30 00:00:00
abstract::We propose a semiparametric method for estimating ROC surfaces for continuous diagnostic tests based on two test measurements. Such a three-class diagnostic problem based on two test measurements arises naturally from some DNA amplification-related diagnostic scenarios. Simulation results show that our proposed semipa...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3625
更新日期:2009-08-15 00:00:00
abstract::In medical and health studies, heterogeneities in clustered count data have been traditionally modeled by positive random effects in Poisson mixed models; however, excessive zeros often occur in clustered medical and health count data. In this paper, we consider a three-level random effects zero-inflated Poisson model...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3619
更新日期:2009-08-15 00:00:00
abstract::A survey is conducted at w of K selection units or lists, e.g. health care institutions or weeks in a year, to estimate N, the total number of individuals with particular characteristics. Our estimator utilizes two items determined for each survey participant: the number, u, among the w lists in S and the number, j, a...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3614
更新日期:2009-07-30 00:00:00
abstract::The percentile-finding experimental design known variously as 'forced-choice fixed-staircase', 'geometric up-and-down' or 'k-in-a-row' (KR) was introduced by Wetherill four decades ago. To date, KR has been by far the most widely used up-and-down (U&D) design for estimating non-median percentiles; it is implemented mo...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3590
更新日期:2009-06-15 00:00:00
abstract::Multivariate outcomes measured longitudinally over time are common in medicine, public health, psychology and sociology. The typical (saturated) longitudinal multivariate regression model has a separate set of regression coefficients for each outcome. However, multivariate outcomes are often quite similar and many out...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3589
更新日期:2009-06-15 00:00:00
abstract::The Wilcoxon-Mann-Whitney (WMW) test is often used to compare the means or medians of two independent, possibly nonnormal distributions. For this problem, the true significance level of the large sample approximate version of the WMW test is known to be sensitive to differences in the shapes of the distributions. Base...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3561
更新日期:2009-05-01 00:00:00
abstract::A new, intuitive method has recently been proposed to explore treatment-covariate interactions in survival data arising from two treatment arms of a clinical trial. The method is based on constructing overlapping subpopulations of patients with respect to one (or more) covariates of interest and in observing the patte...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3524
更新日期:2009-04-15 00:00:00
abstract::The asymptotic Pearson's chi-squared test and Fisher's exact test have long been the most used for testing association in 2x2 tables. Unconditional tests preserve the significance level and generally are more powerful than Fisher's exact test for moderate to small samples, but previously were disadvantaged by being co...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3531
更新日期:2009-03-30 00:00:00
abstract::It has been increasingly common to analyze simultaneously repeated measures and time to failure data. In this paper we propose a joint model when the repeated measures are semi-continuous, characterized by the presence of a large portion of zero values, as well as right skewness of non zero (positive) values. Examples...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3497
更新日期:2009-03-15 00:00:00
abstract::A popular method for analysing repeated-measures data is generalized estimating equations (GEE). When response data are missing at random (MAR), two modifications of GEE use inverse-probability weighting and imputation. The weighted GEE (WGEE) method involves weighting observations by their inverse probability of bein...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3520
更新日期:2009-03-15 00:00:00
abstract::Among many other uses, positron emission tomography (PET) can be used in studies to estimate the density of a neuroreceptor at each location throughout the brain by measuring the concentration of a radiotracer over time and modeling its kinetics. There are a variety of kinetic models in common usage and these typicall...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3510
更新日期:2009-03-15 00:00:00
abstract::We develop a simulation-based procedure for determining the required sample size in binomial regression risk assessment studies when response data are subject to misclassification. A Bayesian average power criterion is used to determine a sample size that provides high probability, averaged over the distribution of po...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3505
更新日期:2009-02-28 00:00:00
abstract::The log-rank test is the most powerful non-parametric test for detecting a proportional hazards alternative and thus is the most commonly used testing procedure for comparing time-to-event distributions between different treatments in clinical trials. When the log-rank test is used for the primary data analysis, the s...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3501
更新日期:2009-02-28 00:00:00
abstract::In this paper we describe Bonferroni-based multiple testing procedures (MTPs) as strategies to split and recycle test mass. Here, 'test mass' refers to (parts of) the nominal level alpha at which the family-wise error rate is controlled. Briefly, test mass is split between different null hypotheses, and whenever a nul...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3513
更新日期:2009-02-28 00:00:00
abstract::For clinical trials with multiple treatment arms or endpoints a variety of sequentially rejective, weighted Bonferroni-type tests have been proposed, such as gatekeeping procedures, fixed sequence tests, and fallback procedures. They allow to map the difference in importance as well as the relationship between the var...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3495
更新日期:2009-02-15 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
pub_type: 杂志文章
doi:10.1002/sim.3493
更新日期:2009-02-15 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
pub_type: 杂志文章
doi:10.1002/sim.3480
更新日期:2009-02-01 00:00:00
abstract::It is not uncommon for a continuous outcome variable Y to be dichotomized and analysed using logistic regression. Moser and Coombs (Statist. Med. 2004; 23:1843-1860) provide a method for converting the output from a standard linear regression analysis using the original continuous outcome Y to give much more efficient...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3474
更新日期:2009-01-30 00:00:00
abstract::In this paper, we construct a partial additive regression (PAR) model to predict the survival times of cancer patients based on microarray gene expression data with right censoring. The area under time-dependent receiver operating characteristic curve is used as a model evaluation criterion. We conduct a simulation st...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3412
更新日期:2009-01-30 00:00:00
abstract::Researchers in clinical science and bioinformatics frequently aim to learn which of a set of candidate biomarkers is important in determining a given outcome, and to rank the contributions of the candidates accordingly. This article introduces a new approach to research questions of this type, based on targeted maximu...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3414
更新日期:2009-01-15 00:00:00
abstract::In the recent years, studies of hepatitis B (HBV) and hepatitis C virus (HCV) dynamics have drawn great attention as they provide insight into the process of virus elimination/production and of infected cells decay during antiviral treatment. Estimates of viral dynamic parameters may be used to determine the lifetime ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3457
更新日期:2008-12-30 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
pub_type: 杂志文章
doi:10.1002/sim.3424
更新日期:2008-12-20 00:00:00
abstract::One is often interested in the ratio of two variables, for example in genetics, assessing drug effectiveness, and in health economics. In this paper, we derive an explicit geometric solution to the general problem of identifying the two tangents from an arbitrary external point to an ellipse. This solution permits num...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3398
更新日期:2008-12-10 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
pub_type: 杂志文章
doi:10.1002/sim.3397
更新日期:2008-12-10 00:00:00
abstract::Shared random effects models have been increasingly common in the joint analyses of repeated measures (e.g. CD4 counts, hemoglobin levels) and a correlated failure time such as death. In this paper we study several shared random effects models in the multi-level repeated measures data setting with dependent failure ti...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3392
更新日期:2008-11-29 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
pub_type: 杂志文章
doi:10.1002/sim.3376
更新日期:2008-11-20 00:00:00
abstract::In many epidemiological studies it is common to resort to regression models relating incidence of a disease and its risk factors. The main goal of this paper is to consider inference on such models with error-prone observations and variances of the measurement errors changing across observations. We suppose that the o...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3343
更新日期:2008-11-10 00:00:00
abstract::Studies involving longitudinal binary responses are widely applied in the health and biomedical sciences research and frequently analyzed by generalized estimating equations (GEE) method. This article proposes an alternative goodness-of-fit test based on the nonparametric smoothing approach for assessing the adequacy ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3315
更新日期:2008-09-30 00:00:00
abstract::Geocoding a study population as completely as possible is an important data assimilation component of many spatial epidemiologic studies. Unfortunately, complete geocoding is rare in practice. The failure of a substantial proportion of study subjects' addresses to geocode has consequences for spatial analyses, some of...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3288
更新日期:2008-09-20 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
pub_type: 杂志文章
doi:10.1002/sim.3202
更新日期:2008-09-20 00:00:00
abstract::We compared eight nominal 95 per cent confidence intervals for the ratio of two Poisson parameters, both assumed small, on their true coverage (the probability that the interval includes the ratio of Poisson parameters) and median width. The commonly used log-linear interval, justified by asymptotic considerations, pr...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3234
更新日期:2008-09-10 00:00:00
abstract::We describe how trends in the vaccination coverage at 19 months of age vary by race/ethnicity; explore the extent to which data required to evaluate a child's up-to-date vaccination status is missing as a result of the scattering of vaccination records among many vaccination providers; evaluate how the prevalence of t...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3223
更新日期:2008-09-10 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
pub_type: 杂志文章
doi:10.1002/sim.3268
更新日期:2008-08-30 00:00:00
abstract::Our objective is to develop a model to estimate the relative risk of disease in each area, Ai, i=1, ... , n, of a region and to identify areas of unusually high or low risk. We use a product partition model (PPM) in which we assume that the true relative risks can be partitioned into a number of components or sets of ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3253
更新日期:2008-08-30 00:00:00
abstract::Genetic networks for gene expression data are often built by graphical models, which in turn are built from pair-wise correlations of gene expression levels. A key feature of building graphical models is the evaluation of conditional independence of two traits, given other traits. When conditional independence can be ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3274
更新日期:2008-08-30 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
pub_type: 杂志文章
doi:10.1002/sim.3238
更新日期:2008-08-15 00:00:00
abstract::We analyze data obtained from a study designed to evaluate training effects on the performance of certain motor activities of Parkinson's disease patients. Maximum likelihood methods were used to fit beta-binomial/Poisson regression models tailored to evaluate the effects of training on the numbers of attempted and su...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3303
更新日期:2008-07-30 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
pub_type: 杂志文章
doi:10.1002/sim.3099
更新日期:2008-06-15 00:00:00