Biostatistics and Epidemiology最新文献_第7页

Essential concepts of causal inference: a remarkable history and an intriguing future 因果推理的基本概念：非凡的历史和迷人的未来

Biostatistics and Epidemiology Pub Date : 2019-01-01 DOI: 10.1080/24709360.2019.1670513

D. Rubin

{"title":"Essential concepts of causal inference: a remarkable history and an intriguing future","authors":"D. Rubin","doi":"10.1080/24709360.2019.1670513","DOIUrl":"https://doi.org/10.1080/24709360.2019.1670513","url":null,"abstract":"ABSTRACT Causal inference refers to the process of inferring what would happen in the future if we change what we are doing, or inferring what would have happened in the past, if we had done something different in the distant past. Humans adjust our behaviors by anticipating what will happen if we act in different ways, using past experiences to inform these choices. ‘Essential’ here means in the mathematical sense of excluding the unnecessary and including only the necessary, e.g. stating that the Pythagorean theorem works for an isosceles right triangle is bad mathematics because it includes the unnecessary adjective isosceles; of course this is not as bad as omitting the adjective ‘right.’ I find much of what is written about causal inference to be mathematically inapposite in one of these senses because the descriptions either include irrelevant clutter or omit conditions required for the correctness of the assertions. The history of formal causal inference is remarkable because its correct formulation is so recent, a twentieth century phenomenon, and its future is intriguing because it is currently undeveloped when applied to investigate interventions applied to conscious humans, and moreover will utilize tools impossible without modern computing.","PeriodicalId":37240,"journal":{"name":"Biostatistics and Epidemiology","volume":"3 1","pages":"140 - 155"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/24709360.2019.1670513","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43617355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 27

Variable selection and nonlinear effect discovery in partially linear mixture cure rate models 部分线性混合固化率模型的变量选择与非线性效应发现

Biostatistics and Epidemiology Pub Date : 2019-01-01 DOI: 10.1080/24709360.2019.1663665

A. Masud, Zhangsheng Yu, W. Tu

{"title":"Variable selection and nonlinear effect discovery in partially linear mixture cure rate models","authors":"A. Masud, Zhangsheng Yu, W. Tu","doi":"10.1080/24709360.2019.1663665","DOIUrl":"https://doi.org/10.1080/24709360.2019.1663665","url":null,"abstract":"Survival data with long-term survivors are common in clinical investigations. Such data are often analyzed with mixture cure rate models. Existing model selection procedures do not readily discriminate nonlinear effects from linear ones. Here, we propose a procedure for accommodating nonlinear effects and for determining the cure rate model composition. The procedure is based on the Least Absolute Shrinkage and Selection Operators (LASSO). Specifically, by partitioning each variable into linear and nonlinear components, we use LASSO to select linear and nonlinear components. Operationally, we model the nonlinear components by cubic B-splines. The procedure adds to the existing variable selection methods an ability to discover hidden nonlinear effects in a cure rate model setting. To implement, we ascertain the maximum likelihood estimates by using an Expectation Maximization (EM) algorithm. We conduct an extensive simulation study to assess the operating characteristics of the selection procedure. We illustrate the use of the method by analyzing data from a real clinical study.","PeriodicalId":37240,"journal":{"name":"Biostatistics and Epidemiology","volume":"3 1","pages":"156 - 177"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/24709360.2019.1663665","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47487854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Modeling exposures with a spike at zero: simulation study and practical application to survival data 零峰值暴露的建模:生存数据的模拟研究和实际应用

Biostatistics and Epidemiology Pub Date : 2019-01-01 DOI: 10.1080/24709360.2019.1580463

E. Lorenz, C. Jenkner, W. Sauerbrei, H. Becher

{"title":"Modeling exposures with a spike at zero: simulation study and practical application to survival data","authors":"E. Lorenz, C. Jenkner, W. Sauerbrei, H. Becher","doi":"10.1080/24709360.2019.1580463","DOIUrl":"https://doi.org/10.1080/24709360.2019.1580463","url":null,"abstract":"Risk and prognostic factors in epidemiological and clinical research are often semicontinuous such that a proportion of individuals have exposure zero, and a continuous distribution among those exposed. We call this a spike at zero (SAZ). Typical examples are consumption of alcohol and tobacco, or hormone receptor levels. To additionally model non-linear functional relationships for SAZ variables, an extension of the fractional polynomial (FP) approach was proposed. To indicate whether or not a value is zero, a binary variable is added to the model. In a two-stage procedure, called FP-spike, it is assessed whether the binary variable and/or the continuous FP function for the positive part is required for a suitable fit. In this paper, we compared the performance of two approaches – standard FP and FP-spike – in the Cox model in a motivating example on breast cancer prognosis and a simulation study. The comparisons lead to the suggestion to generally using FP-spike rather than standard FP when the SAZ effect is considerably large because the method performed better in real data applications and simulation in terms of deviance and functional form. Abbreviations: CI: confidence interval; FP: fractional polynomial; FP1: first degree fractional polynomial; FP2: second degree fractional polynomial; FSP: function selection procedure; HT: hormone therapy; OR: odds ratio; SAZ: spike at zero","PeriodicalId":37240,"journal":{"name":"Biostatistics and Epidemiology","volume":"3 1","pages":"23 - 37"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/24709360.2019.1580463","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48298967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

A frequentist mixture modeling of stop signal reaction times 停止信号反应时间的频率混合建模

Biostatistics and Epidemiology Pub Date : 2019-01-01 DOI: 10.1080/24709360.2019.1660110

M. Soltanifar, A. Dupuis, R. Schachar, M. Escobar

{"title":"A frequentist mixture modeling of stop signal reaction times","authors":"M. Soltanifar, A. Dupuis, R. Schachar, M. Escobar","doi":"10.1080/24709360.2019.1660110","DOIUrl":"https://doi.org/10.1080/24709360.2019.1660110","url":null,"abstract":"The stop signal reaction time (SSRT), a measure of the latency of the stop signal process, has been theoretically formulated using a horse race model of go and stop signal processes by the American scientist Gordon Logan (1994). The SSRT assumes equal impact of the preceding trial type (go/stop) on its measurement. In the case of a violation of this assumption, we consider estimation of SSRT based on the idea of earlier analysis of cluster type go reaction times (GORT) and linear mixed model (LMM) data analysis results. Two clusters of trials were considered including those trials preceded by a go trial and other trials preceded by a stop trial. Given disparities between cluster type SSRTs, we need to consider some new indexes considering the unused cluster type information in the calculations. We introduce mixture SSRT and weighted SSRT as two new distinct indexes of SSRT that address the violated assumption. Mixture SSRT and weighted SSRT are theoretically asymptotically equivalent under special conditions. An example of stop single task (SST) real data is presented to show equivalency of these two new SSRT indexes and their larger magnitude compared to Logan's single 1994 SSRT. Abbreviations: ADHD: attention deficit hyperactivity disorder; ExG: Ex-Gaussiandistribution; GORT: reaction time in a go trial; GORTA: reaction time in a type A gotrial; GORTB: reaction time in a type B go trial; LMM: linear mixed model; SWAN:strengths and weakness of ADHD symptoms and normal behavior rating scale; SSD: stop signal delay; SR: signal respond; SRRT: reaction time in a failedstop trial; SSRT: stop signal reaction times in a stop trial; SST: stop signaltask.","PeriodicalId":37240,"journal":{"name":"Biostatistics and Epidemiology","volume":"3 1","pages":"108 - 90"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/24709360.2019.1660110","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41851070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Exact inference for the Youden index to discriminate individuals using two-parameter exponentially distributed pooled samples 使用双参数指数分布的混合样本对约登指数进行区分个体的精确推断

Biostatistics and Epidemiology Pub Date : 2019-01-01 DOI: 10.1080/24709360.2019.1587264

Sumith Gunasekera, Lakmali Weerasena, Aruna Saram, O. Ajumobi

{"title":"Exact inference for the Youden index to discriminate individuals using two-parameter exponentially distributed pooled samples","authors":"Sumith Gunasekera, Lakmali Weerasena, Aruna Saram, O. Ajumobi","doi":"10.1080/24709360.2019.1587264","DOIUrl":"https://doi.org/10.1080/24709360.2019.1587264","url":null,"abstract":"It has become increasingly common in epidemiological studies to pool specimens across subjects as a useful cot-cutting technique to achieve accurate quantification of biomarkers and certain environmental chemicals. The data collected from these pooled samples can then be utilized to estimate the Youden Index, which measures biomarker's effectiveness and aids in the selection of an optimal threshold value, as a summary measure of the Receiver Operating Characteristic curve. The aim of this paper is to make use of generalized approach to estimate and testing of the Youden index. This goal is accomplished by the comparison of classical and generalized procedures for the Youden Index with the aid of pooled samples from the shifted-exponentially distributed biomarkers for the low-risk and high-risk patients. These are juxtaposed using confidence intervals, p-values, power of the test, size of the test, and coverage probability with a wide-ranging simulation study featuring a selection of various scenarios. In order to demonstrate the advantages of the proposed generalized procedures over its classical counterpart, an illustrative example is discussed using the Duchenne Muscular Dystrophy data available at http://biostat.mc.vanderbilt.edu/wiki/Main/DataSets or http://lib.stat.cmu.edu/datasets/.","PeriodicalId":37240,"journal":{"name":"Biostatistics and Epidemiology","volume":"3 1","pages":"38 - 61"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/24709360.2019.1587264","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48586931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Effect of modeling a multilevel structure on the Indian population to identify the factors influencing HIV infection 对印度人口进行多层次结构建模以确定影响HIV感染的因素的效果

Biostatistics and Epidemiology Pub Date : 2019-01-01 DOI: 10.1080/24709360.2019.1671096

Nidhiya Menon, Binukumar Bhaskarapillai, A. Richardson

{"title":"Effect of modeling a multilevel structure on the Indian population to identify the factors influencing HIV infection","authors":"Nidhiya Menon, Binukumar Bhaskarapillai, A. Richardson","doi":"10.1080/24709360.2019.1671096","DOIUrl":"https://doi.org/10.1080/24709360.2019.1671096","url":null,"abstract":"ABSTRACT Many studies have addressed the factors associated with HIV in the Indian population. Some of these studies have used sampling weights for the risk estimation of factors associated with HIV, but few studies have adjusted for the multilevel structure of survey data. The National Family Health Survey 3 collected data across India between 2005 and 2006. 38,715 females and 66,212 males with complete information were analyzed. To account for the correlations within clusters, a three-level model was employed. Bivariate and multivariable mixed effect logistic regression analysis were performed to identify factors associated with HIV. Intracluster correlation coefficients were used to assess the relatedness of each pair of variables within clusters. Variables pertaining to no knowledge of contraceptive methods, age at first marriage, wealth index and noncoverage of PSUs by Anganwadis were significant risk factors for HIV when the multileveled model was used for analysis. This study has identified the risk profile for HIV infection using an appropriate modeling strategy and has highlighted the consequences of ignoring the structure of the data. It offers a methodological guide towards an applied approach to the identification of future risk and the need to customize intervention to address HIV infection in the Indian population.","PeriodicalId":37240,"journal":{"name":"Biostatistics and Epidemiology","volume":"3 1","pages":"126 - 139"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/24709360.2019.1671096","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46923546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The 9-criteria evaluation framework for perceptions survey: the case of VA’s Learners’ Perceptions Survey 认知调查的9项标准评估框架——以弗吉尼亚大学学生认知调查为例

Biostatistics and Epidemiology Pub Date : 2018-12-16 DOI: 10.1080/24709360.2018.1553362

T. Kashner, Christopher Clarke, D. Aron, John M. Byrne, G. Cannon, D. Deemer, S. Gilman, C. Kaminetzky, L. Loo, Sophia Li, Annie B. Wicker, S. Keitz

{"title":"The 9-criteria evaluation framework for perceptions survey: the case of VA’s Learners’ Perceptions Survey","authors":"T. Kashner, Christopher Clarke, D. Aron, John M. Byrne, G. Cannon, D. Deemer, S. Gilman, C. Kaminetzky, L. Loo, Sophia Li, Annie B. Wicker, S. Keitz","doi":"10.1080/24709360.2018.1553362","DOIUrl":"https://doi.org/10.1080/24709360.2018.1553362","url":null,"abstract":"ABSTRACT For its clinical, epidemiologic, educational, and health services research, evaluation, administrative, regulatory, and accreditation purposes, the perceptions survey is a data collection tool that asks observers to describe perceptions of their experiences with a defined phenomenon of interest. In practice, these surveys are often subject to criticism for not having been thoroughly evaluated before its first application using a consistent and comprehensive set of criteria for validity and reliability. This paper introduces a 9-criteria framework to assess perceptions surveys that integrates criteria from multiple evaluation sources. The 9-criteria framework was applied to data from the Department of Veterans Affairs’ Learners’ Perceptions Survey (LPS) that had been administered to national and local samples, and from findings obtained through a literature review involving LPS survey data. We show that the LPS is a robust tool that may serve as a model for design and validation of other perceptions surveys. Findings underscore the importance of using all nine criteria to validate perceptions survey data.","PeriodicalId":37240,"journal":{"name":"Biostatistics and Epidemiology","volume":"4 1","pages":"140 - 171"},"PeriodicalIF":0.0,"publicationDate":"2018-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/24709360.2018.1553362","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48159892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

An introduction to the why and how of risk adjustment 介绍风险调整的原因和方法

Biostatistics and Epidemiology Pub Date : 2018-09-17 DOI: 10.1080/24709360.2018.1519990

W. B. Vogel, Guoqing Chen

引用次数: 2

Clinical trials design and conduct 临床试验的设计和实施

Biostatistics and Epidemiology Pub Date : 2018-06-07 DOI: 10.1080/24709360.2018.1477467

W. Henderson

引用次数: 0

Quasi-experimental design 准实验设计

Biostatistics and Epidemiology Pub Date : 2018-06-07 DOI: 10.1080/24709360.2018.1477468

M. Maciejewski

引用次数: 31