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Inconsistency between overall and subgroup analyses

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General Psychiatry 2022年第3期35卷 201-204页

作者： Hongyue Wang Bokai Wang xin m tu Changyong Feng Departments of Biostatistics&Computational Biology University of RochesterRochesterNew YorkUSA Division of Biostatistics and Bioinformatics Herbert Wertheim School of Public Health and Human Longevity ScienceUC San DiegoLa JollaCaliforniaUSA

Suppose we have a sample of subjects in two treatment *** study the difference of the treatment effects,we can analyse the data using all subjects(overall analysis).We may also divide the subjects into several subgroups based on some covariates of interest(eg,gender),and study the treatment effects within each *** results of these two analyses may be different or even in opposite *** this paper,we give a general sufficient condition of consistency between the overall and subgroup analyses.

关键词： subgroup consistency groups.

On modelling relative risks for longitudinal binomial responses:implications from two dueling paradigms

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General Psychiatry 2023年第2期36卷 143-147页

作者： tuo Lin Rongzhe Zhao Shengjia tu Hao Wu Hui Zhang xin m tu Division of Biostatistics and Bioinformatics Herbert Wertheim School of Public Health and Human Longevity ScienceUC San DiegoLa JollaCaliforniaUSA College of Environmental Science and Engineering Tongji UniversityShanghaiChina Department of mathematics and Statistics Georgia State UniversityAtlantaGeorgiaUSA Division of Biostatistics Department of Preventive MedicineNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA

Although logistic regression is the most popular for modelling regression relationships with binary responses,many find relative risk(RR),or risk ratio,easier to interpret and prefer to use this measure of risk in regression ***,since Zou published his modified Poisson regression approach for modelling RR for cross-sectional data,his paper has been cited over 7000 times,demonstrating the popularity of this alternative measure of risk in regression analysis involving binary *** longitudinal studies have become increasingly popular in clinical trials and observational studies,it is imperative to extend Zou’s approach for longitudinal *** two most popular approaches for longitudinal data analysis are the generalised linear mixed-effects model(GLmm)and generalised estimating equations(GEE).However,the parametric GLmm cannot be used for the extension within the current context,because Zou’s approach treats the binary response as a Poisson variable,which is at odds with the Bernoulli distribution for the binary *** the other hand,as it imposes no mathematical model on data distributions,the semiparametric GEE is coherent with Zou’s modified Poisson *** this paper,we develop a GEE-based longitudinal model for binary responses to provide inference about RR.

关键词： sectional coherent estimating

Post-hoc power analysis:a conceptually valid approach for power based on observed study data

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General Psychiatry 2022年第4期35卷 266-272页

作者： Natalie E Quach Kun Yang Ruohui Chen Justin tu manfei Xu xin m tu xinlian Zhang Division of Biostatistics and Bioinformatics Herbert Wertheim School of Public Health and Human Longevity ScienceUC San DiegoLa JollaCaliforniaUSA Department of Orthopedics Emory HealthcareEmory UniversityAtlantaGeorgiaUSA Shanghai mental Health Center Shanghai Jiao Tong University School of MedicineShanghaiChina

Power analysis is a key component of planning prospective studies such as clinical ***,some journals in biomedical and psychosocial sciences request power analysis for data already collected and analysed before acceptingmanuscripts for *** have raised concerns about the conceptual basis for such post-hoc power *** recently,Zhang et al showed by using simulation studies that such power analyses do not indicate true power for detecting statistical significance since post-hoc power estimates vary in the range of practical interests and can be very different from the true *** the other hand,journals'request for information about the reliability of statistical findings in a manuscript due to small sample sizes is justified since the sample size plays an important role in the reproducibility of statistical *** problem is the wording of the journals'request,as the current power analysis paradigm is not designed to address journals'concerns about the reliability of the statistical *** this paper,we propose an alternate formulation of power analysis to provide a conceptually valid approach to the journals'wrongly worded but practically significant concern.

关键词： power approach sizes

The p-value and model specification in statistics

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General Psychiatry 2019年第3期32卷 163-166页

作者： Bokai Wang Zhirou Zhou Hongyue Wang xin m tu Changyong Feng Departments of Biostatistics and Computational Biology and Anesthesiology University of Rochester Rochester New York USA Family medicine and Public Health University of California San Diego San Diego. California USA Naval Health Research Center San Diego California USA

SUmmARY The p value has been widely used as a way to summarise the significance in data analysis. However, misuse and misinterpretation of the p value is common in practice. Our result shows that if the model specification is wrong, the distribution of the p value may be inappropriate, which makes the decision based on the p value invalid.

关键词： p-value model specification statistics

Post hoc power analysis:is it an informative and meaningful analysis?

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General Psychiatry 2019年第4期32卷 221-225页

作者： Yiran Zhang Rita Hedo Anna Rivera Rudolph Rull Sabrina Richardson xin m tu Department of Family medicine and Public Health University of California SystemOaklandCaliforniaUSA Naval Health Research Center San DiegoCaliforniaUSA Leidos San DiegoCaliforniaUSA

Power analysis is a key component for planning prospective studies such as clinical trials. However, some journals in biomedical and psychosocial sciences ask for power analysis for data already collected and analysed before accepting manuscripts for publication. In this report, post hoc power analysis for retrospective studies is examined and the informativeness of understanding the power for detecting significant effects of the results analysed, using the same data on which the power analysis is based, is scrutinised. monte Carlo simulation is used to investigate the performance of posthoc power analysis.

关键词： power analysis meaningful analysis

Guidance for use of weights: an analysis of different types of weights and their implications when using SAS PROCs

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General Psychiatry 2019年第1期32卷 49-55页

作者： Sabrina Richardson tuo Lin Yangyi Li Xiaohui Niu manfei Xu Valerie Stander xin m tu The Henry m.Jackson Foundation for the Advancement of military medicine Inc BethesdaMarylandUnited States military Population Health Naval Health Research CenterSan DiegoCaUnited States Clinical and Translational Research Institute University of California San DiegoSan DiegoCaliforniaUSA School of mathematical and Statistical Sciences Clemson UniversityClemsonSouth CarolinaUSA College of Informatics Huazhong Agriculture UniversityWuhanChina Shanghai mental Health Center Medical CollegeShanghai Jiao Tong UniversityShanghaiChina

SAS and other popular statistical packages provide support for survey data with sampling weights. For example, PROC mEANS and PROC LOGISTIC in SAS have their counterparts PROC SURVEYmEANS and PROC SURVEYLOGISTIC to facilitate analysis of data from complex survey studies. On the other hand, PROC mEANS and many other classic SAS procedures also provide an option for including weights and yield identical point estimates, but different standard errors (SEs), as their corresponding survey procedures. This paper takes an in-depth look at different types of weights and provides guidance on use of different SAS procedures.

关键词： Guidance use of weights analysis

machine learning methods in psychiatry: a brief introduction

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General Psychiatry 2020年第1期33卷 20-22页

作者： Zhirou Zhou Tsung-Chin Wu Bokai Wang Hongyue Wang xin m tu Changyong Feng Department of Biostatistics and Computational Biology University of RochesterRochesterNew YorkUSA Department of mathematics University of California San DiegoLa JollaCaliforniaUSA Family medicine and Public Health University of California San DiegoLa JollaCaliforniaUSA Naval Health Research Center San DiegoCaliforniaUSA

machine learning(mL)techniques have been widely used to address mental health *** discuss two main aspects of mL in psychiatry in this paper,that is,supervised learning and unsupervised *** are used to illustrate how ... 详细信息

关键词： learning illustrate brief

Partial least squares regression and principal component analysis:similarity and differences between two popular variable reduction approaches

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General Psychiatry 2022年第1期35卷 67-71页

作者： Chenyu Liu xinlian Zhang Tanya T Nguyen Jinyuan Liu Tsungchin Wu Ellen Lee xin m tu Division of Biostatistics and Bioinformatics Herbert Wertheim School of Public Health and Human Longevity ScienceUC San DiegoLa JollaCaliforniaUSA Department of Psychiatry Stein Institute for Research on AgingUC San DiegoLa JollaCaliforniaUSA

SUmmARY In many statistical applications,composite variables are constructed to reduce the number of variables and improve the performances of statistical analyses of these variables,especially when some of the variables are highly *** component analysis(PCA)and factor analysis(FA)are generally used for such *** the variables are used as explanatory or independent variables in linear regression analysis,partial least squares(PLS)regression is a better *** PCA and FA,PLS creates composite variables by also taking into account the response,or dependent variable,so that they have higher correlations with the response than composites from their PCA and FA *** this report,we provide an introduction to this useful approach and illustrate it with data from a real study.

关键词： composite composites component

Tests for paired count outcomes

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General Psychiatry 2018年第4期31卷 48-53页

作者： James A Proudfoot tuo Lin Bokai Wang xin m tu Clinical and Translational Research Institute University of California San Diego Departments of Biostatistics& Computational Biology and Anesthesiology University of Rochester Department of Family medicine and Public Health University of California San Diego

Paired t-tests are widely used to compare differences in paired continuous outcomes. This test, however, does not apply to non-continuous outcomes. For binary outcomes,mcNemar's test is the de facto method for comparing differences in paired binary variables. For count or frequency outcomes, there is not much discussion in the literature. The Wilcoxon signed-rank test is often used to assess differences in paired count outcomes. However, like the mann-Whitney U test, or Wilcoxon rank-sum test for comparing two independent groups, the Wilcoxon signedrank test is generally not efficient(powerful). In this essay,we consider some alternative methods for comparing paired count outcomes and compare them with the Wilcoxon signed-rank test using monte Carlo simulations.

关键词： Tests for paired count outcomes