382,456 papers found

This article presents a methodological review of 54 meta-analyses of the effectiveness of clinical psychological treatments, using standardized mean differences as the effect size index. We statistically analyzed the distribution of the number of studies of the meta-analyses, the distribution of the sample sizes in the…

Meta-analysis of neuroimaging results has proven to be a popular and valuable method to study human brain functions. A number of studies have used meta-analysis to parcellate distinct brain regions. A popular way to perform meta-analysis is typically based on the reported activation coordinates from a number of publish…

Meta-analysis is an important tool for synthesizing research on a variety of topics in ecology and evolution, including molecular ecology, but can be susceptible to nonindependence. Nonindependence can affect two major interrelated components of a meta-analysis: (i) the calculation of effect size statistics and (ii) th…

OBJECTIVE: The objective was to estimate the presence and extent to which potentially unnecessary and therefore maybe wasteful clinical trials regarding relevant interventions and outcomes in major clinical areas had been conducted. STUDY DESIGN AND SETTING: From current Cochrane collaboration systematic reviews in ma…

OBJECTIVES: In randomized controlled clinical trials, continuous outcomes are typically measured at both baseline and follow-up, and mean difference could be estimated using the change scores from baseline or the follow-up scores. This study assesses the impact of using change score vs. follow-up score on the conclusio…

In prognostic studies, a summary statistic such as a hazard ratio is often reported between low-expression and high-expression groups of a biomarker with a study-specific cutoff value. Recently, several meta-analyses of prognostic studies have been reported, but these studies simply combined hazard ratios provided by t…

AIM: Vote counting is frequently used in meta-analyses to rank biomarker candidates, but to our knowledge, there have been no independent assessments of its validity. Here, we used predictions from a recent meta-analysis to determine how well number of supporting studies, combined sample size and mean fold change perfo…

INTRODUCTION: Individual participant data (IPD) systematic reviews and meta-analyses are often considered to be the gold standard for meta-analysis. In the ten years since the first review into the methodology and reporting practice of IPD reviews was published much has changed in the field. This paper investigates cur…

Heterogeneity in meta-analysis is most commonly estimated using a moment-based approach described by DerSimonian and Laird. However, this method has been shown to produce biased estimates. Alternative methods to estimate heterogeneity include the restricted maximum likelihood approach and those proposed by Paule and Ma…

OBJECTIVES: To investigate how often systematic reviewers encounter multiple trial effect estimates that are available for inclusion in a particular meta-analysis (multiplicity of results) and the methods they use to select effect estimates. STUDY DESIGN AND SETTING: We randomly sampled Cochrane and MEDLINE-indexed no…

A meta-analysis of studies on intracranial tumors and mobile phone use published by the end of 2012 was performed to evaluate the overall consistency of findings, assess the sensitivity of results to changes in the dataset, and try to detect the sources of between-study heterogeneity. Twenty-nine papers met our inclusi…

In meta-analysis, between-study heterogeneity indicates the presence of effect-modifiers and has implications for the interpretation of results in cost-effectiveness analysis and decision making. A distinction is usually made between true variability in treatment effects due to variation in patient populations or setti…

BACKGROUND: Proper scientific reporting is necessary to ensure the correct interpretation of study results by readers. The main objective of this study was to assess the quality of reporting in abstracts of systematic reviews (SRs) with meta-analyses in periodontology and implant dentistry. Differences in reporting of…