392,186 papers found

Systematic reviews and meta-analyses are being increasingly used to summarize medical literature and identify areas in which research is needed. Systematic reviews limit bias with the use of a reproducible scientific process to search the literature and evaluate the quality of the individual studies. If possible the re…

In our article (Storm, Tressoldi, & Di Risio, 2010), we claimed that the ganzfeld experimental design has proved to be consistent and reliable. However, Hyman (2010) argues that the overall evidence for psi is, in fact, contradictory and elusive. We present a case for psi research that undermines Hyman's argument. Firs…

A meta-analysis is a research procedure aiming, within the context of evidence based medicine, to combine the results of several studies in a systematic and quantifiable way. The technique is particularly useful where the individual studies give contradictory or inconclusive results. Interest in meta-analyses has incre…

This article discusses the meta-analysis of raw mean differences. It presents a rationale for cumulating psychological effects in a raw metric and compares raw mean differences to standardized mean differences. Some limitations of standardization are noted, and statistical techniques for raw meta-analysis are described…

Two studies compared the Schmidt-Hunter method of meta-analysis (J. E. Hunter & F. L. Schmidt, 1990) with the method described by L. V. Hedges and J. L. Vevea (1998). Study 1 evaluated estimates of rho, sigmarho, and resulting credibility intervals for both models through Monte Carlo methods. Results showed slight diff…

A 1998 meta-analysis by B. Rind, P. Tromovitch, and R. Bauserman in Psychological Bulletin indicated that the relations between child sexual abuse and later psychopathology were weak in magnitude. Shortly thereafter, this article was condemned by media personality Dr. Laura Schlessinger and numerous conservative organi…

At a time when scientists support Evidence-Based Medicine, the Parliament of Belgium has recently decided to recognize four alternative medicines, among which homeopathy. Whereas this discipline does not rely on any scientific basis, it appears to be popular, especially in general practice. The homeopaths have recently…

Genome searches have been performed for many complex traits, and in some cases several searches have been performed in a single disease. Replication of significant results is rare, and a systematic method of reviewing results from a number of searches is needed. A method for meta-analysis is presented which provides a…

Meta-analysis is increasingly appearing in the epidemiologic literature. Although originally performed in the context of experimental or randomized controlled study designs and with regard to problems that are amenable to these designs, the method has also been applied to studies in observational epidemiologic settings…

Meta-analyses as currently practiced are usually retrospective. They can be made more rigorous by developing a protocol that incorporates prospectively the elements that are usually necessary in a well-designed trial. Meta-analysis and large trials are complementary. Meta-analysis of small trials is useful in generatin…

In spite of an abundance of data, the empirical evidence as yet does not make clear whether meta-analysis will bring about progress in psychological science. Therefore, it is still useful and desirable to engage in rational analysis of the methodology. Such analysis is done in the present essay by posing five questions…

It is likely that more studies that use meta-analysis will be published in the endocrinologic literature. Major strengths of meta-analysis are the systematic ascertainment of research on a given topic and the explicit delineation of reasons for accepting or rejecting studies as a basis for drawing conclusions. The tend…

The effect models are defined as the simple or complex relation that the risk in the treatment group follows when the risk in the control group varies. The standard statistical methods of meta-analysis are based on simple effect models. The use of these methods could induce inaccurate or erroneous results in more compl…

Meta-analysis is an epidemiological and statistical tool used to combine the results of independent studies and synthesize their conclusions for the purpose of evaluating therapeutic effectiveness, determining procedural efficacy, or providing a basis for development of treatment protocols. Meta-analysis also may be de…

In this paper we shall present the general principles of meta-analysis and will then discuss the various factors needed to evaluate a meta-analysis: description of the problem; definition of the outcome(s) (primary and secondary); methods for identifying and selecting trials for inclusion; statistical methods used; and…

Meta-analysis is the process of formally combining the quantitative results of separate studies in order to increase the statistical precession of estimated effects. It has become fashionable when individual studies fail to yield conclusive results. A recent update of a meta-analysis (overview) for treatments of patien…

Lymphangioleiomyomatosis is a rare disease which afflicts young women of childbearing age. It is sufficiently uncommon that randomization or any other systematic evaluation of regimens of treatment has been difficult. Review of scattered case reports implies that a number of hormonal manipulations may be equally effect…

Consumer satisfaction with medical care was examined in a meta-analysis of 221 studies. For each study, (1) a coding form was filled out that described sample characteristics, design, and instrument methodology, and (2) the study sample's overall satisfaction level was transformed to a 0.00-1.00 scale. This article sum…

Bang and Zhao address an important methodological gap by proposing meta-analytic methods for cost-effectiveness analysis (CEA) based on separate pooling of incremental costs (ΔC) and incremental effectiveness (ΔE), with summaries displayed on the cost-effectiveness plane. We share the aim of expanding the t…

There is a deficit between existing levels of paediatric clinical research in low- and middle-income countries (LMICs) and what is warranted based on the disease burden in children in these countries. Lack of market protections, low ability to pay and cost-based pricing are key commercial barriers to industry-funded pa…