392,240 papers found

Safety meta-analyses could play an important role in capturing fragmented safety data from underpowered clinical studies. Their utility, however, is hampered by the same constraints surrounding clinical studies, including limited external validity, inconsistent classification and the underreporting of safety data. When…

Using meta-analysis in health care research is a common practice. Here we are interested in methods used for analysis of time-to-event data. Particularly, we are interested in their performance when there is a low event rate. We consider three methods based on the Cox proportional hazards model, including a Bayesian ap…

Cronbach's coefficient alpha is the most widely used estimator of the reliability of tests and scales. However, it has been criticized as being a lower bound and hence underestimating true reliability. A popular alternative to coefficient alpha is composite reliability, which is usually calculated in conjunction with s…

Standard meta-analyses are an effective tool in evidence-based medicine, but one of their main drawbacks is that they can compare only two alternative treatments at a time. Moreover, if no trials exist which directly compare two interventions, it is not possible to estimate their relative efficacy. Multiple treatments…

In anterior resection of rectum, the section level of inferior mesenteric artery is still subject of controversy between the advocates of high and low tie. The low tie is the division and ligation to the branching of the left colic artery and the high tie is the division and ligation at its origin at the aorta. We inte…

The M3 workshop has, as its primary focus, the rapidly growing area of metagenomics, including the metadata standards and the meta-analysis approaches needed to organize, process and interpret metagenomics data. The PSB Workshop builds on the first M3 meeting, a Special Interest Group (SIG) meeting at ISMB 2009, organi…

Individuals with diabetes have an increased risk of cardiovascular disease. Epidemiological studies demonstrate that plasma glucose (PG) concentrations in the upper normal range are an independent risk factor for cardiovascular disease, as discussed in a meta-analysis. Studies carried out mainly in the general populati…

(1) A prospective study in Germany showed that 12% of hospitalised children experienced adverse drug reactions. These reactions were the reason for hospitalisation in 1.8% of cases. (2) A meta-analysis of 17 prospective studies of adverse drug reactions in children, published in 2001, and two French prospective studies…

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…

Effect size is used in single studies to complement inferential statistical analysis. It also is used to compare and synthesize data across studies in meta-analysis. Effect size provides information about clinical importance of differences found in research observations. For researchers, effect size is useful in establ…

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…