382,008 papers found

In the present article, a commonly used meta-analytic procedure for handling dependent effect sizes from a single sample was examined, and 2 revised procedures that estimate and incorporate the degree of interdependence were proposed. The authors' simulation results reveal that the commonly used procedure that averages…

In this commentary, a meta-analytic review by D. Westen and K. Morrison (2001) is put in a historical context of the controversies over the effects of psychotherapy. It is suggested that recalculations of the effects of psychotherapy have been common in past debates and that Westen and Morrison's estimates understate t…

The authors suggest that D. Westen and K. Morrison's (2001) meta-analysis of treatment is critically limited in the consideration of measurement and mechanisms of therapeutic change. The measures included in the analysis fail to represent a comprehensive coverage of the domains within which change is expected. Moreover…

Missing data occur frequently in meta-analysis. Reviewers inevitably face decisions about how to handle missing data, especially when predictors in a model of effect size are missing from some of the identified studies. Commonly used methods for missing data such as complete case analysis and mean substitution often yi…

Knowledge concerning aetiologic hypotheses can be obtained through systematic reviews of observational studies. In observational studies, heterogeneity between studies is expected, because of differences in study design and analysis. Data from observational studies have to be made comparable before pooling of results f…

The most important target of "evidence-based laboratory medicine(EBLM)", based on the fundamental concept of evidence-based medicine(EBM) is to improve appropriate, effective utilization of laboratory tests through close communication between clinical laboratories and clinicians. It is mandatory for clinicians to know…

Clinical evaluation of modern phytotherapy is mainly carried out today using the method of meta-analysis. These generally reveal a marked contradiction of the results of individual clinical studies. There are various hypotheses to explain this fact: in the first place the products used are often of a different chemical…

The number needed to treat (NNT) is an increasingly popular way of presenting the effects of treatment. However, the NNT varies markedly depending on the baseline risk of patients, the outcome considered, and the clinical setting. Furthermore geographic and secular trends make the NNT unstable between places and over t…

Quality aspects get more important in internal medicine due to novel technical developments and economic constraints. In spite of an extensive research activity in clinical medicine some research aspects of quality control are new. Among these are investigations about symptoms and complaints as well as risk factors. To…

Based on a meta-analysis of published studies, it has been estimated that approximately 10% of coronary artery disease cases are attributable to hyperhomocyst(e)inemia. It has also been calculated that food fortification with folate might reduce the number of cases of coronary artery disease in the United States by 50,…

Modern attempts to link intake of salt with population blood pressure (BP) show striking similarity to early 19th century attitudes which attributed human disease and premature death to inappropriate diet. Under these circumstances there is a danger that conviction of the truth of a hypothesis may lead to selection of…

Meta-analysis is essential for obtaining reproducible summaries of study results and valuable for discovering patterns among study results. A good meta-analysis will highlight and delineate the subjective components of these processes and vigorously search for sources of heterogeneity. Unfortunately, these objective ar…

Cross-design synthesis is a new (and still evolving) strategy for providing quantitative results that capture the strengths and minimize the weaknesses of different kinds of research. The strategy, which is being developed to answer questions about the effects of treatment in medical practice, includes (a) identifying…

This article describes a collection of meta-analysis techniques based on Bayesian statistics for interpreting, adjusting, and combining evidence to estimate parameters and outcomes important to the assessment of health technologies. The result of an analysis by the Confidence Profile Method is a joint posterior probabi…