Comparison of Software Algorithms for Calculating REML Wald Type Confidence Limits for the Between-Group Variance Component in a Small Sample One-Way Random Effects Model Example

2010 ◽  
Vol 64 (1) ◽  
pp. 83-87
Author(s):  
Henry S. Lynn ◽  
Zhanjian Dong ◽  
Zhe Mu
2000 ◽  
Vol 25 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Lynn Friedman

In meta-analyses, groups of study effect sizes often do not fit the model of a single population with only sampling, or estimation, variance differentiating the estimates. If the effect sizes in a group of studies are not homogeneous, a random effects model should be calculated, and a variance component for the random effect estimated. This estimate can be made in several ways, but two closed form estimators are in common use. The comparative efficiency of the two is the focus of this report. We show here that these estimators vary in relative efficiency with the actual size of the random effects model variance component. The latter depends on the study effect sizes. The closed form estimators are linear functions of quadratic forms whose moments can be calculated according to a well-known theorem in linear models. We use this theorem to derive the variances of the estimators, and show that one of them is smaller when the random effects model variance is near zero; however, the variance of the other is smaller when the model variance is larger. This leads to conclusions about their relative efficiency.


2020 ◽  
Author(s):  
Jincheng Huang ◽  
Kun Zou ◽  
Ping Yuan ◽  
Longhao Zhang ◽  
Min Yang ◽  
...  

Abstract Background: Congenital auricle deformities (CADs) not only affect the appearance, but may also result in social inferiority or difficulties, influence the hearing and mental health of the children. Although some studies have pointed out CADs have a natural improvement trend, there is still a lack of high-quality research to demonstrate the degree of that. Therefore, related studies agree that early treatment are necessary. Ear mold correction is currently main non-surgical treatment for CADs, but the existing research often involves a small sample size, and the research conclusions are inconsistent. More importantly, there is still no systematic review on ear mold correction for CADs. This study aims to systematically evaluate the effectiveness and safety of ear mold correction for CADs, so as to provide an evidence base for further research.Methods: The study has been designed according to the Preferred Reporting program for Systems Evaluation and Meta-analysis Protocol (PRISMA-P). We will search electronic literature databases of PubMed, Embase, Cochrane Library, Web of science, CBM, CNKI, Wanfang and VIP from their initiative to 1 June 2020 for interventional studies on ear mould for children with CADs. The study selection, data extraction and quality assessment will be performed by two authors. Meta-analysis will be conducted on primary outcome effectiveness rate of physician assessment and secondary outcomes of effectiveness rate of parents’ assessment, effectiveness score, hearing assessment, and adverse reactions using relative ratio or mean difference and their 95% confidence intervals. The heterogeneity of the included studies will be tested using Chi square test and I2, and random-effects model will be used when significant heterogeneity was found, otherwise, fixed-effects model will be used. Sensitivity analysis will be performed using trials with high quality and using alternative [1]models (fixed-effects or random effects model). Publication bias will be tested using funnel plot and Egger’s test. Discussion: This study will be the first to systematically evaluate the effectiveness and safety of ear mold correction for CADs, to provide evidence base for clinical guideline making, clinical decision and future research. Systematic review registration : CRD42020190982.


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