The trace plot is seldom used in meta-analysis, yet it is a very informative plot. In this article, we define and illustrate what the trace plot is, and discuss why it is important. The Bayesian version of the plot combines the posterior density of [tau], the between-study standard deviation, and the shrunken estimates of the study effects as a…

The application of network meta-analysis is becoming increasingly widespread, and for a successful implementation, it requires that the direct comparison result and the indirect comparison result should be consistent. Because of this, a proper detection of inconsistency is often a key issue in network meta-analysis as whether the results can be…

Many statistical methods (estimators) are available for estimating the consensus value (or average effect) and heterogeneity variance in interlaboratory studies or meta-analyses. These estimators are all valid because they are developed from or supported by certain statistical principles. However, no estimator can be perfect and must have error or…

Publication bias threatens meta-analysis validity. It is often assessed via the funnel plot; an asymmetric plot implies small-study effects, and publication bias is one cause of the asymmetry. Egger's regression test is a widely used tool to quantitatively assess such asymmetry. It examines the association between the observed effect sizes and…

Meta-analyses of diagnostic test accuracy (DTA) studies have been gaining prominence in research in clinical epidemiology and health technology development. In these DTA meta-analyses, some studies may have markedly different characteristics from the others and potentially be inappropriate to include. The inclusion of these "outlying"…

Meta-analyses in orphan diseases and small populations generally face particular problems, including small numbers of studies, small study sizes and heterogeneity of results. However, the heterogeneity is difficult to estimate if only very few studies are included. Motivated by a systematic review in immunosuppression following liver…

Practical meta-analysis of correlation matrices generally ignores covariances (and hence correlations) between correlation estimates. The authors consider various methods for allowing for covariances, including generalized least squares, maximum marginal likelihood, and Bayesian approaches, illustrated using a 6-dimensional response in a series of…

In light of a recent revelation that Gersten (1985) included erroneous information on one of two programs for English Language Learners (ELLs), the authors re-calculate results of their earlier meta-analysis of program effectiveness studies for ELLs in which Gersten's studies had behaved as outliers (Rolstad, Mahoney & Glass, 2005). The correction…

Two new methods for constructing a credibility interval (CI)--an interval containing a specified proportion of true validity description--are discussed, from a frequentist perspective. Tolerance intervals, unlike the current method of constructing the CI, have performance characteristics across repeated applications and may be useful in validity…

The use of a Bayesian approach in evaluating data from clinical trials with many treatment centers and from many studies is discussed. The main distinction between a metaanalysis and an analysis of a multicenter trial is that different studies may have very different designs, while the centers in a multicenter trial usually follow the same…

A model is proposed to account for publication bias explicitly using a weight function that describes probability of publication for a particular study in terms of a selection parameter. A Bayesian analysis of this model using Gibbs sampling is conducted, and the model is applied to a published meta-analysis. (SLD)

Background/Context: This essay reviews recent demographic literature on school transitions. I describe how a demographic perspective, by which I mean using methods that are standard in the study of population processes, is a useful way to examine differences in access to and completion of post secondary schooling in the United States.…

To facilitate meta-analysis of diverse study findings, a mixed linear model with fixed random effects is presented and illustrated with data from teacher expectancy experiments. The standardized effect size is viewed as random and the variation among effect sizes is modeled as a function of study characteristics. (Author/BS).

In 1994, R. G. Lord and P. E. Levy proposed a variant of control theory that incorporated human information processing principles. The current article evaluates the empirical evidence for their propositions and updates the theory by considering contemporary research on information processing. Considerable support drawing from diverse literatures…

Analyses for results of a series of studies examining intercorrelations among a set of as many as p+1 variables are presented. Several estimators of a pooled or average correlation vector and its variances are derived for cases in which some studies do not report complete correlation matrices. A test of the homogeneity (consistency) of the…