392,350 papers found

When data come from several independent studies for the purpose of estimating treatment control differences, meta-analysis can be carried out either on the best linear unbiased estimators computed from each study or on the pooled individual patient data modelled as a two-way model without interaction, where the two fac…

Meta-analysis is a method of data analysis applied to summarizing research findings, both quantitative and qualitative summaries of individual studies. Rooted in the fundamental values of the scientific enterprise of replicability, causal and correlational analysis, it is useful for answering three general questions: W…

The objective of this study was to determine the validity and reliability achieved in employing trained graduate students to read and evaluate the methodologic content of papers analyzing the health effects of electromagnetic field radiation. The search identified 11,730 references from multiple sources, of which 8759…

Meta-analysis is a quantitative process of summary and interpretation which involves pooling information from independent studies concerning a single theme in order to draw conclusions. Greatly increased employment of meta-analysis is currently being advocated for clinical and policy decision making. However, the prest…

A method of stratifying the data according to the patterns of missing observations, summarizing each subject's repeated measurements by a summary measure and then comparing the treatment groups with the help of a distribution-free test based on the summary measure, is used here to compare the efficacy of tacrine dose r…

Current methods for meta-analysis still leave a number of unresolved issues, such as the choice between fixed- and random-effects models, the choice of population distribution in a random-effects analysis, the treatment of small studies and extreme results, and incorporation of study-specific covariates. We describe ho…

In order to quantify the impact of therapeutic drug monitoring (TDM) services on the average number of serum drug assays (SDAs) ordered for patients, a meta-analysis was conducted on the data collected from 16 published and unpublished studies. Overall, TDM has no effect on the number of SDAs ordered per patient. Howev…

Modern quantitative evidence synthesis methods often combine patient-level data from different sources, known as individual participants data (IPD) sets. A specific challenge in meta-analysis of IPD sets is the presence of systematically missing data, when certain variables are not measured in some studies, and sporadi…

Methods for random-effects meta-analysis require an estimate of the between-study variance, τ. The performance of estimators of τ(measured by bias and coverage) affects their usefulness in assessing heterogeneity of study-level effects and also the performance of related estimators of the overall effect. Ho…

Exercise stimulates a wide array of biological processes, but the mechanisms involved are incompletely understood. Many previous studies have adopted transcriptomic analyses of skeletal muscle to address particular research questions, a process that ultimately results in the collection of large amounts of publicly avai…

OBJECTIVES: The number of systematic reviews that aim to compare multiple interventions using network meta-analysis is increasing. In this study, we highlight aspects of a standard systematic review protocol that may need modification when multiple interventions are to be compared. STUDY DESIGN AND SETTING: We take th…

OBJECTIVE: Three recent meta-analyses have made the claim, albeit with some caveats, that cognitive-behavioral treatments (CBT) are superior to other psychotherapies, in general or for specific disorders (e.g., social phobia). METHOD: The purpose of the present article was to examine four issues in meta-analysis that…

The aim of this overview was to evaluate and compare the quality of systematic reviews, with or without meta-analysis, that have evaluated studies on techniques or biomaterials used for the preservation of alveolar sockets post tooth extraction in humans. An electronic search was conducted without date restrictions usi…

In a recent research article in BMC Medicine, Créquit and colleagues demonstrate how published systematic reviews in lung cancer provide a fragmented, out-of-date picture of the evidence for all treatments. The results and conclusions drawn from this study, based on cumulative network meta-analyses (NMA) of eviden…

Meta-analysis offers ecologists a powerful tool for knowledge synthesis. Albeit a form of review, it also shares many similarities with primary empirical research. Consequently, critical reading of meta-analyses incorporates criteria from both sets of approaches particularly because ecology is a discipline that embrace…

OBJECTIVE: The objective of this paper is to describe the course "Systematic Reviews and Meta-analysis" at the Johns Hopkins Bloomberg School of Public Health. METHODS: A distinct feature of our course is a group project in which students, assigned to multi-disciplinary groups, conduct a systematic review. In-class se…

Research has shown that forest plots are a gold standard in the visualization of meta-analytic results. However, research on the general interpretation of forest plots and the role of researchers' meta-analysis experience and field of study is still unavailable. Additionally, the traditional display of effect sizes, co…

BACKGROUND: Systematic reviews now routinely assess methodological quality to gauge the validity of the included studies and of the synthesis as a whole. Although trends from higher quality studies should be clearer, it is uncertain how often meta-analyses incorporate methodological quality in models of study results e…

OBJECTIVE: Rheumatoid arthritis (RA) is a complex disorder with many genetic and environmental factors to account for disease susceptibility. Individual genetic association studies usually suffer from small sample size leading to biased results of polymorphisms association with RA liability. Therefore, meta-analyses se…