382,895 papers found

Many meta-analysis models contain multiple parameters, for example due to multiple outcomes, multiple treatments or multiple regression coefficients. In particular, meta-regression models may contain multiple study-level covariates, and one-stage individual participant data meta-analysis models may contain multiple pat…

Systematic reviews and meta-analyses (SRMAs) are increasingly used in epilepsy research to rigorously address clinical questions and inform patient care. Consequently, the ability to conduct and interpret SRMAs is essential for professionals in this field. This educational article offers a step-by-step guide to perform…

We introduce a new meta-analysis estimator, the weighted and iterated least squares (WILS), that greatly reduces publication selection bias (PSB) when selective reporting for statistical significance (SSS) is present. WILS is the simple weighted average that has smaller bias and rates of false positives than convention…

The number of studies published in the biomedical literature has dramatically increased over the last few decades. This massive proliferation of literature makes clinical medicine increasingly complex, and information from multiple studies is often needed to inform a particular clinical decision. However, available stu…

An ongoing debate exists over the role of percutaneous coronary intervention and coronary artery bypass grafting for revascularization in patients with multivessel or left main disease. Despite improvements in stent technology, bypass surgery still provides the best long-term results in the majority of patients. The pr…

Published studies in Medicine (and virtually any other discipline) sometimes report that a difference or correlation did not reach statistical significance but do not report its effect size or any statistic from which the latter may be derived. Unfortunately, meta-analysts should not exclude these studies because their…

OBJECTIVES: The systematic review (SR) is a research methodology that aims to synthesize related evidence. Updating previously conducted SRs is necessary when new evidence has been produced, but no consensus has yet emerged on the appropriate update methodology. The authors have developed a new SR update method called…

OBJECTIVE: To demonstrate why meta-analytic methods need modification before they can be used to aggregate rates or effect sizes in outcomes research, under the constraint of no common underlying effect or rate. METHODS: Studies are presented that require different types of risk adjustment. First, we demonstrate using…

There is debate whether clinical trials with suboptimal power are justified and whether results from large studies are more reliable than the (combined) results of smaller trials. We quantified the error rates for evaluations based on single conventionally powered trials (80% or 90% power) versus evaluations based on t…

Meta-analyses constitute fundamental tools of the Evidence-Based Medicine (EBM) aiming at synthesizing outcome data from individual trials in order to produce pooled effect estimates for various outcomes of interest. Combining summary data from several studies increases the sample size, improves the statistical power o…

The standard estimator for the log odds ratio (the unconditional maximum likelihood estimator) and the delta-method estimator for its standard error are not defined if the corresponding 2 × 2 table contains at least one "zero cell". This is also an issue when estimating the overall log odds ratio in…

We present the R package and web app statcheck to automatically detect statistical reporting inconsistencies in primary studies and meta-analyses. Previous research has shown a high prevalence of reported p-values that are inconsistent - meaning a re-calculated p-value, based on the reported test statistic and degrees…

INTRODUCTION: Meta-analysis is the cornerstone of robust biomedical evidence. OBJECTIVES: We investigated whether statistical reporting practices facilitate metabolomics meta-analyses. METHODS: A literature review of 44 studies that used a comparable platform. RESULTS: Non-numeric formats were used in 31 studies.&#x…

The current paper is a call for and illustration of a way of closing the gap between basic research and professional practice in the field of neurorehabilitation. Methodologically, single-case experimental designs and the guidelines created regarding their conduct are highlighted. Statistically, we review two data anal…

This article is the first in a series of six articles related to systematic reviews in animal agriculture and veterinary medicine. In this article, we overview the methodology of systematic reviews and provide a discussion of their use. Systematic reviews differ qualitatively from traditional reviews by explicitly defi…

Writing the variance of the Mantel-Haenszel estimator under the null of homogeneity and inverting the corresponding test, we arrive at an improved confidence interval for the common risk difference in stratified 2 × 2 tables. This interval outperforms a variety of other intervals currently recommende…

Methods of network meta-analysis (NMA) can be classified as arm-based and contrast-based approaches. There are several arm-based approaches, and some of these have been criticized because they recover inter-study information and hence do not obey the principle of concurrent control. Here, we point out that recovery of…

Odds ratios and risk ratios are useful measures of effect size in 2-group studies in which the response variable is dichotomous. Confidence interval methods are proposed for combining and comparing odds ratios and risk ratios in multistudy designs. Unlike the traditional fixed-effect meta-analysis methods, the proposed…

This article is a continuation of a 2-part series that seeks to build the skills of health care managers and supervisors in critically reading and interpreting systematic reviews and meta-analyses. The first article, part I, defined the types of systematic reviews and outlined the process of conducting them. This artic…