解剖学和形态学
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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
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牙科,口腔外科和医学
皮肤病学
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卫生保健科学和服务
血液学
免疫学
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医学信息学
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医学,全科和内科
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神经系统科学
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眼科学
整形外科学
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病理学
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药理学和药剂学
生理学
基本医疗保健
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呼吸系统
风湿病学
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外科学
毒理学
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泌尿学和肾脏学
病毒学
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健康政策和服务
心理学,临床
abstract::Ordinal data appear in a wide variety of scientific fields. These data are often analyzed using ordinal logistic regression models that assume proportional odds. When this assumption is not met, it may be possible to capture the lack of proportionality using a constrained structural relationship between the odds and t...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5689
更新日期:2013-06-15 00:00:00
abstract::The use of the continual reassessment method (CRM) and other model-based approaches to design Phase I clinical trials has increased owing to the ability of the CRM to identify the maximum tolerated dose better than the 3 + 3 method. However, the CRM can be sensitive to the variance selected for the prior distribution ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5621
更新日期:2013-06-15 00:00:00
abstract::In observational studies, many continuous or categorical covariates may be related to an outcome. Various spline-based procedures or the multivariable fractional polynomial (MFP) procedure can be used to identify important variables and functional forms for continuous covariates. This is the main aim of an explanatory...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5639
更新日期:2013-06-15 00:00:00
abstract::The matched case-control designs are commonly used to control for potential confounding factors in genetic epidemiology studies especially epigenetic studies with DNA methylation. Compared with unmatched case-control studies with high-dimensional genomic or epigenetic data, there have been few variable selection metho...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5694
更新日期:2013-05-30 00:00:00
abstract::Methods for addressing multiplicity in clinical trials have attracted much attention during the past 20 years. They include the investigation of new classes of multiple test procedures, such as fixed sequence, fallback and gatekeeping procedures. More recently, sequentially rejective graphical test procedures have bee...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5711
更新日期:2013-05-10 00:00:00
abstract::Zero-inflated Poisson regression is a popular tool used to analyze data with excessive zeros. Although much work has already been performed to fit zero-inflated data, most models heavily depend on special features of the individual data. To be specific, this means that there is a sizable group of respondents who endor...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5650
更新日期:2013-04-30 00:00:00
abstract::In this paper, we proposed a mechanistic breast cancer survival model based on the axillary lymph node chain structure, considering lymph nodes as a potential dissemination arrangement. We assume a naive breast cancer treatment protocol consisting of exposing patients first to a chemotherapy treatment on r intervals a...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5576
更新日期:2013-04-30 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
pub_type: 杂志文章
doi:10.1002/sim.5624
更新日期:2013-04-15 00:00:00
abstract::In many practical applications, count data often exhibit greater or less variability than allowed by the equality of mean and variance, referred to as overdispersion/underdispersion, and there are several reasons that may lead to the overdispersion/underdispersion such as zero inflation and mixture. Moreover, if the c...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5560
更新日期:2013-04-15 00:00:00
abstract::In England and Wales, a large-scale multiple statistical surveillance system for infectious disease outbreaks has been in operation for nearly two decades. This system uses a robust quasi-Poisson regression algorithm to identify abberrances in weekly counts of isolates reported to the Health Protection Agency. In this...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5595
更新日期:2013-03-30 00:00:00
abstract::Epidemiologic and clinical studies routinely collect longitudinal measures of multiple outcomes, including biomarker measures, cognitive functions, and clinical symptoms. These longitudinal outcomes can be used to establish the temporal order of relevant biological processes and their association with the onset of cli...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5557
更新日期:2013-03-15 00:00:00
abstract::In longitudinal studies, missing observations occur commonly. It has been well known that biased results could be produced if missingness is not properly handled in the analysis. Authors have developed many methods with the focus on either incomplete response or missing covariate observations, but rarely on both. The ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5536
更新日期:2013-02-28 00:00:00
abstract::Sample size planning should reflect the primary objective of a trial. If the primary objective is prediction, the sample size determination should focus on prediction accuracy instead of power. We present formulas for the determination of training set sample size for survival prediction. Sample size is chosen to contr...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5550
更新日期:2013-02-28 00:00:00
abstract::In many studies, interest lies in determining whether members of the study population will undergo a particular event of interest. Such scenarios are often termed 'mover-stayer' scenarios, and interest lies in modelling two sub-populations of 'movers' (those who have a propensity to undergo the event of interest) and ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5529
更新日期:2013-02-20 00:00:00
abstract::I reflect on the statistical methods of the Christakis-Fowler studies on network-based contagion of traits by checking the sensitivity of these kinds of results to various alternate specifications and generative mechanisms. Despite the honest efforts of all involved, I remain pessimistic about establishing whether bin...
journal_title:Statistics in medicine
pub_type: 评论,杂志文章
doi:10.1002/sim.5551
更新日期:2013-02-20 00:00:00
abstract::The change in c-statistic is frequently used to summarize the change in predictive accuracy when a novel risk factor is added to an existing logistic regression model. We explored the relationship between the absolute change in the c-statistic, Brier score, generalized R(2) , and the discrimination slope when a risk f...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5598
更新日期:2013-02-20 00:00:00
abstract::Biological drug products are therapeutic moieties manufactured by a living system or organisms. These are important life-saving drug products for patients with unmet medical needs. Because of expensive cost, only a few patients have access to life-saving biological products. Most of the early biological products will ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5565
更新日期:2013-02-10 00:00:00
abstract::In recent years, follow-on biological products (biosimilars) have received much attention from both the biotechnology industry and the regulatory agencies, especially after the passage of the 2010 healthcare reform bill. Unlike the traditional small-molecule drug products, the development of biological products is not...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5568
更新日期:2013-02-10 00:00:00
abstract::The problem for assessing biosimilarity and drug interchangeability of follow-on biologics (biosimilar products) is studied. Unlike the generic products, the development of biosimilar products is much more complicated because of fundamental differences in functional structures and manufacturing processes. As a result,...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5571
更新日期:2013-02-10 00:00:00
abstract::In genetic association studies, it is typically thought that genetic variants and environmental variables jointly will explain more of the inheritance of a phenotype than either of these two components separately. Traditional methods to identify gene-environment interactions typically consider only one measured enviro...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5444
更新日期:2013-01-30 00:00:00
abstract::Genome-wide association studies are characterized by a huge number of statistical tests performed to discover new disease-related genetic variants [in the form of single-nucleotide polymorphisms (SNPs)] in human DNA. Many SNPs have been identified for cross-sectionally measured phenotypes. However, there is a growing ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5517
更新日期:2013-01-15 00:00:00
abstract::Systematic reviews often provide recommendations for further research. When meta-analyses are inconclusive, such recommendations typically argue for further studies to be conducted. However, the nature and amount of future research should depend on the nature and amount of the existing research. We propose a method ba...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5524
更新日期:2013-01-15 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
pub_type: 杂志文章
doi:10.1002/sim.5585
更新日期:2012-12-30 00:00:00
abstract::A common but not necessarily logical requirement in drug development is that a 'limit of quantitation' be set for chemical assays and that observations that fall below the limit should not be treated as real data but should be labelled as below the limit and set aside for special treatment. We examine five of seven ap...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5515
更新日期:2012-12-30 00:00:00
abstract:BACKGROUND:Multiple imputation is becoming increasingly popular for handling missing data, with Markov chain Monte Carlo assuming multivariate normality (MVN) a commonly used approach. Imputing categorical variables (which are clearly non-normal) using MVN imputation is challenging, and several approaches have been sug...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5445
更新日期:2012-12-30 00:00:00
abstract::In record linkage studies, unique identifiers are often not available, and therefore, the linkage procedure depends on combinations of partially identifying variables with low discriminating power. As a consequence, wrongly linked covariate and outcome pairs will be created and bias further analysis of the linked data...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5498
更新日期:2012-12-30 00:00:00
abstract::Measures that quantify the impact of heterogeneity in univariate meta-analysis, including the very popular I(2) statistic, are now well established. Multivariate meta-analysis, where studies provide multiple outcomes that are pooled in a single analysis, is also becoming more commonly used. The question of how to quan...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5453
更新日期:2012-12-20 00:00:00
abstract::Providing personalized treatments designed to maximize benefits and minimizing harms is of tremendous current medical interest. One problem in this area is the evaluation of the interaction between the treatment and other predictor variables. Treatment effects in subgroups having the same direction but different magni...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5429
更新日期:2012-12-10 00:00:00
abstract::In this paper, we consider a full likelihood method to analyze continuous longitudinal responses with non-ignorable non-monotone missing data. We consider a transition probability model for the missingness mechanism. A first-order Markov dependence structure is assumed for both the missingness mechanism and observed d...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5359
更新日期:2012-12-10 00:00:00
abstract::In biomedical research such as the development of vaccines for infectious diseases or cancer, study outcomes measured by an assay or device are often collected from multiple sources or laboratories. Measurement error that may vary between laboratories needs to be adjusted for when combining samples across data sources...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5446
更新日期:2012-12-10 00:00:00
abstract::Paired data from matched case-control studies are commonly used to estimate the association between the exposure to a risk factor and the occurrence of a disease. The odds ratio is typically used to quantify this association. Difficulties in estimating the true odds ratio with matched pairs arise, however, when the ex...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5355
更新日期:2012-11-30 00:00:00
abstract::Case-control studies are prone to low power for testing gene-environment interactions (GXE) given the need for a sufficient number of individuals on each strata of disease, gene, and environment. We propose a new study design to increase power by strategically pooling biospecimens. Pooling biospecimens allows us to in...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5357
更新日期:2012-11-20 00:00:00
abstract::The problem of testing symmetry about zero has a long and rich history in the statistical literature. We introduce a new test that sequentially discards observations whose absolute value is below increasing thresholds defined by the data. McNemar's statistic is obtained at each threshold and the largest is used as the...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5384
更新日期:2012-11-20 00:00:00
abstract::Clinical trials, especially the randomized clinical trial, have been and will remain the gold standard for the evaluation of new interventions, including pharmaceuticals, biologics, medical devices, procedures, or behavioral modifications. Despite more than five decades of experience, there are still challenges in the...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5405
更新日期:2012-11-10 00:00:00
abstract::Comparative effectiveness research represents the kind of research that arguably more directly affects clinical practice and policy. It includes observational studies, clinical trials, and systematic syntheses of existing literature. In this commentary, I argue for the ongoing and critical role of randomization in com...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5400
更新日期:2012-11-10 00:00:00
abstract::Although the frequentist paradigm has been the predominant approach to clinical trial design since the 1940s, it has several notable limitations. Advancements in computational algorithms and computer hardware have greatly enhanced the alternative Bayesian paradigm. Compared with its frequentist counterpart, the Bayesi...
journal_title:Statistics in medicine
pub_type: 杂志文章,评审
doi:10.1002/sim.5404
更新日期:2012-11-10 00:00:00
abstract::Diagnostic problems in medicine are sometimes polytomous, meaning that the outcome has more than two distinct categories. For example, ovarian tumors can be benign, borderline, primary invasive, or metastatic. Extending the main measure of binary discrimination, the c-statistic or area under the ROC curve, to nominal ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5321
更新日期:2012-10-15 00:00:00
abstract::The need for resource-intensive laboratory assays to assess exposures in many epidemiologic studies provides ample motivation to consider study designs that incorporate pooled samples. In this paper, we consider the case in which specimens are combined for the purpose of determining the presence or absence of a pool-w...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4426
更新日期:2012-09-28 00:00:00
abstract::The coefficient of individual equivalence is a permutation-based measure of agreement between two observers making replicated readings on each subject. It compares the observed disagreement between the observers to the expected disagreement under individual equivalence. Individual equivalence of observers requires tha...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5323
更新日期:2012-09-10 00:00:00
abstract::Motivated by a previously published study of HIV treatment, we simulated data subject to time-varying confounding affected by prior treatment to examine some finite-sample properties of marginal structural Cox proportional hazards models. We compared (a) unadjusted, (b) regression-adjusted, (c) unstabilized, and (d) s...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5317
更新日期:2012-08-30 00:00:00