392,010 papers found

Although well developed to assess efficacy questions, meta-analyses and, more generally, systematic reviews, have received less attention in application to safety-related questions. As a result, many open questions remain on how best to apply meta-analyses in the safety setting. This appraisal attempts to: (i) summariz…

Meta-analysis is a method in common use for data analysis in evidence-based medicine. In this paper, based on the Mantel-Haenszel and Peto methods used for Meta-analysis of the data on 2 x 2 table, we put forward a simple calculating method for clinicians. It is useful for Meta-analysis and can be easily applied to ana…

Calculations of the power of statistical tests are important in planning research studies (including meta-analyses) and in interpreting situations in which a result has not proven to be statistically significant. The authors describe procedures to compute statistical power of fixed- and random-effects tests of the mean…

Meta-analysis is a relatively new development in medicine. It is conceptually appealing, summarizing the medical literature in a rigorous manner and providing clinicians with a global picture regarding the merits of interventions. This process can help clinicians choose appropriate, evidence-based management options fo…

Including all relevant material--good, bad, and indifferent--in meta-analysis admits the subjective judgments that meta-analysis was designed to avoid. Several problems arise in meta-analysis: regressions are often non-linear; effects are often multivariate rather than univariate; coverage can be restricted; bad studie…

A summary is provided for the relevant issues that investigators must address when wishing to synthesize data via a meta-analysis. The analogy is made to conducting a clinical trial and its components. Both design and statistical issues are discussed with the goal of assuring that the proper elements are included in th…

The progression of scientific knowledge requires replication of research results and an orderly accumulation of research knowledge. However, developmental science, like many other sciences, has too often prioritized individual studies at the expense of replication and synthesis efforts. In this chapter, I describe the…

UNLABELLED: The metahdep package contains tools for combining the results of multiple gene expression studies. Unlike previous microarray meta-analysis packages, metahdep accounts for both sampling and hierarchical dependence among studies, as well as fundamental covariate differences between studies. AVAILABILITY: ht…

Studies showing favourable results tend to be published more than once. This practice of duplicate publication is, however, dishonest and unethical on the part of scientists and pharmaceutical companies. Inclusion into a meta-analysis of the results from multiple papers derived from one and the same controlled study gi…

This article examines the usefulness of meta-analysis, and articulates many of the criticisms that have been made of its workings. An attempt is made to outline the precautions that have to be taken before a scientifically useful and meaningful meta-analysis can be carried out. The problems encountered include heteroge…

The main points of in the letter by Kopylev and Dzierlenga can be summarized as: (1) if the difference of two parameter estimates is not statistically significant, then using either one can be considered a reasonable representation of a parameter for use in a meta-analysis, and (2) that we calculated the estimand in ou…

The results of a meta-analysis are more than just the reported odds ratio, 95% confidence interval (CI), and p value. Of equal importance is the fine print of the study which should include assessment of the risk of bias, certainty in evidence, and heterogeneity in the individual point estimates and CIs. These areas al…

The article provides an introduction to interpreting meta-analysis in the context of synthesizing results of studies that examine the role of culture on drug use behaviors. Topics reviewed include using effect size to indicate the strength of a relationship in a primary study, combining effects in weighted models to yi…

Meta-analysis is becoming increasingly used in contemporary nursing to synthesize the evidence from the biomedical literature. However, interpreting the meta-analysis graph continues to remain a problem for many clinicians. The purpose of this article is to provide clinicians with a basic understanding of the meta-anal…

Beginning with Florence Nightingale, nurses have attempted to base their practice on the best evidence. Research findings often form part of the evidence for practice. The proliferation of studies and the frequent contradictory findings between studies make it difficult to determine the scientific basis for practice. I…