392,145 papers found

This article is a broad review of the approaches, findings, and applications of meta-analyses on clinical neuropsychological topics. The review is divided into four sections: basic characteristics of meta-analysis; the value of meta-analysis for neuropsychological investigations; illustrative findings from various meta…

Wise and colleagues (Ann. Hum. Genet. (1999) 63: 263-72) introduced a rank-based statistical technique for meta-analysis of genome scans, the Genome Scan Meta-Analysis (GSMA) method. We provide an alternative derivation of the null distribution of the GSMA statistic, with extensions, and we suggest approximations to th…

Whether you are a policy maker of social scientist, you are slowly being drowned in a sea of often inconsistent research data. Proponents of meta-analysis claim that such data can be objectively and usefully summarized for you. The author notes how the assumptions of the meta-analytic model preclude the synthesis of ex…

In meta-analysis, when the difference in results between studies is greater than would be expected by chance, one needs to investigate whether the observed variation in results across studies is associated with clinical and/or methodological differences between studies. This article reviews methods used in meta-analysi…

The paper surveyes the principles and the models of meta-analysis and gives the basic statistical formulae. For evaluation of data of clinical trials two illustrative examples are presented: 1. evaluation of association and homogeneity in fixed and random models of the common standardized treatment effects measured by…

We describe the history and current status of the meta-analytic enterprise. The advantages and historical criticisms of meta-analysis are described, as are the basic steps in a meta-analysis and the role of effect sizes as chief coins of the meta-analytic realm. Advantages of the meta-analytic procedures include seeing…

By using a published meta-analysis as an example, this paper discusses the use of L'Abbe plot for investigating the potential sources of heterogeneity in meta-analysis. As compared with other graphic procedures, the L'Abbe plot is useful to identify not only the studies having different results from other studies, but…

The trustworthiness of meta-analysis, a set of techniques used to quantitatively combine results from different studies, has recently been questioned. Problems with meta-analysis stem from bias in selecting studies to include in a meta-analysis and from combining study results when it is inappropriate to do so. Simple…

Medicine has been dominated by uncontrolled data, often of unproven validity and insufficient to answer clinically important questions pertaining to individual patients. Controlled clinical trials, when designed and conducted rigorously, offer advantages over uncontrolled data, but they cannot be done for everything an…

The efficacy of a drug is a quantitative concept rather than a qualitative one. This quantity is expressed by several efficacy indices. None of them meet all the requirements. However, that of absolute benefit is especially suitable for the patients because it tells them the exact gain they can expect from taking the t…

Although nurses have begun to use meta-analysis, a review of the nursing literature demonstrates that its use has not been maximized. Meta-analysis can be employed to synthesize descriptive as well as experimental research, yet attention in nursing has focused almost exclusively on meta-analysis techniques for, and met…

Meta-analysis replaced statistical significance with effect size in the hope of resolving controversy concerning evaluation of treatment effects. Statistical significance measured reliability of the effect of treatment, not its efficacy. It was strongly influenced by the number of subjects investigated. Effect size as…

Meta-analysis can be used in cost-effectiveness studies when evidence from several studies is combined to identify which therapies are effective; to estimate the degree of effectiveness between alternative choices; and to estimate cost-related outcomes as part of the costing of therapies and their sequelae. When meta-a…

Meta-analysis is the structured and systematic qualitative and quantitative integration of the results of several independent studies (i.e. the epidemiology of results). As in any epidemiological study, a meta-analysis needs to start with clearly stated aims and objectives. Attention needs to be paid to selection bias…

Results of 14 randomized controlled trials of acupuncture for chronic pain were pooled in a meta-analysis and analysed in three subgroups according to site of pain; and in two subgroups each according to type to trial, type of treatment, type of control, 'blindness' of participating agents, trial size, and type of jour…

In meta-analysis format the effectiveness of Beck's cognitive therapy for depression was reviewed. Twenty-eight studies were identified that used a common outcome measure of depression, and comparisons of cognitive therapy with other therapeutic modalities were made. The results document a greater degree of change for…