meta-analysis

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meta-analysis

a method by which the results of a number of quantitative studies can be analysed together to produce an overall impression from a field of research. This method lays emphasis on EFFECT SIZE as well as providing a SIGNIFICANCE TEST for the results. It has advantages over a conventional review in that it forces the analyst to evaluate the method and the results of a study more critically and that it provides an objective method for synthesizing the results from such studies. There are two basic approaches to meta-analysis. The first and most common approach involves combining the results from the studies in order to produce a single effect size, inferential statistic and probability. The second approach involves comparing studies which differ over some aspect of their method to see if the results of studies which utilized one design or measure differ from the results of studies employing a different design or method. By combining the results of a number of studies, meta-analysis can circumvent the problems of low STATISTICAL POWER which may characterize the individual studies. (See Cooper; 1998; Cooper and Hedges, 1994; Rosenthal, 1991)
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BioGaia AB (STO:BIOGB), a Swedish healthcare company that develops, markets and sells probiotic products with documented health benefits, announced on Wednesday that two recent new meta-analyses have been published investigating the effects of L.
Conventional pairwise meta-analyses for all outcomes and comparisons were performed using a random-effects model by STATA (version 12.
Gage, Cook, and Reichow investigated the influence of publication bias on meta-analyses conducted in special education.
This article begins by reviewing the logic for greater uptake of systematic literature reviews and meta-analyses in policy analysis.
However, the potential strengths of meta-analyses significantly rely on their reporting quality.
Methods: Electronic database PubMed (between 1966 and June 2015) was searched for systematic reviews and meta-analyses using following search terms: ("garlic" OR "allium sativum" OR "allicin" OR "organosulfur") AND ("cardiovascular" OR "coronary" OR "cholesterol" OR "triglyceride" OR "atherosclerosis" OR "blood pressure" OR "hypertension" OR "blood glucose") AND ("systematic review" OR "meta- analysis"), with no restriction to calendar data and language.
As with all publications, the usefulness of meta-analyses depends largely on the manner in which they are conducted.
As meta-analyses allow for the pooling of data when studies are sufficiently similar in design and endpoint, they enable interpretation and observation of effect across a greater population.
Although it is true that meta-analyses allow researchers to improve statistical power by increasing the probability of finding the effect of an intervention by combining the individual results of several studies--especially when the studies lack an appropriate sample size, it is also true that meta-analyses offer us the opportunity to clarify why results may differ in the direction of effect depending on the characteristics of the studies.
To conduct this assessment, random-effects meta-analyses were used to generate weighted group mean differences and 95% confidence intervals (CIs) between the EPA+DHA group and the placebo group.
The six meta-analyses incorporated a total of 26 randomized trials of beta-blockers versus placebo.
The results of these analyses, in addition, demonstrate the extent to which researchers may be confident in previously conducted meta-analyses that did not have the tools to adjust the effects and variance in such designs.