Standard models for network meta-analysis simultaneously estimate multiple relative treatment effects. In practice, after estimation, these multiple estimates usually pass through a formal or informal selection procedure, eg, when researchers draw conclusions about the effects of the best performing treatment in the network. In this paper, we…

Randomised trials are often funded by commercial companies and methodological studies support a widely held suspicion that commercial funding may influence trial results and conclusions. However, these studies often have a risk of confounding and reporting bias. The risk of confounding is markedly reduced in meta-epidemiological studies that…

Randomized clinical trials underpin evidence-based clinical practice, but flaws in their conduct may lead to biased estimates of intervention effects and hence invalid treatment recommendations. The main approach to the empirical study of bias is to collate a number of meta-analyses and, within each, compare the results of trials with and without…

Background: Stratified medicine seeks to identify patients most likely to respond to treatment. Individual participant data (IPD) network meta-analysis (NMA) models have greater power than individual trials to identify treatment-covariate interactions (TCIs). Treatment-covariate interactions contain "within" and "across" trial…

Background: The efficacy of three dietary treatments for ADHD has been repeatedly tested in randomized controlled trials (RCTs). These interventions are restricted elimination diets (RED), artificial food colour elimination (AFCE) and supplementation with free fatty acids (SFFA). There have been three systematic reviews and associated…

The lack of a unified definition of giftedness leads researchers to use very different operationalizations when selecting a sample of gifted individuals for use in research. We found 104 empirical articles from 38 journals that differentiated between gifted and nongifted students which were analyzed to determine the most common methods of…

This review investigates the state of teacher self- and collective efficacy research conducted from 1998 to 2009. Two hundred and eighteen empirical articles published in 1998-2009 were examined for key characteristics and compared to research published in the previous 12 years (i.e., 1986-1997). Results from the review show increases in overall…

Recent findings from a Mathematica study comparing the performance of teachers prepared via alternative and traditional routes have been interpreted to suggest that policymakers and practitioners should expand the use of fast-entry alternative routes and seek teachers trained through such programs, as they presumably perform as well in the…

In meta-analysis, the usual way of assessing whether a set of single studies is homogeneous is by means of the Q test. However, the Q test only informs meta-analysts about the presence versus the absence of heterogeneity, but it does not report on the extent of such heterogeneity. Recently, the I[squared] index has been proposed to quantify the…

Three major methods of survey research, face-to-face interviews, telephone interviews, and mail questionnaires, are compared with respect to the quality of the data. The literature on experimental comparisons of these methods is reviewed, and the effects of the mode of data collection on aspects of data quality are examined. The effects of the…

The recent releases of two major international comparative studies that addressed mathematics--the Trends in International Mathematics and Science Study 2003 (TIMSS 2003) and the Program for International Student Assessment 2003 (PISA 2003)--provide opportunities and challenges for mathematics education researchers interested in using the…

This report collects the results of all available studies using valid empirical methods to compare segregation in public and private schools, both in general and in the context of school voucher programs. Examining the widespread claims that private schools have high segregation levels and vouchers will lead to greater segregation, this report…

Current thought about the effects of single-parenting on children's sex-role development has supported (1) the traditional view that being raised in a single-parent home is deleterious to the well-being of children; (2) the conditional view noting that differences exist between children in father-absent and father-present homes (but only in…

Addresses the implicit assumption that instructional media represent meaningful experimental variables independent of instructional content or strategy. Results of computer-based instruction (CBI) studies (both well-designed and flawed) and meta-analyses are reviewed to support the authors' position that this assumption is invalid, and new…

Computer-based instruction (CBI) studies analyzed by Kulik et al. were examined to explore the validity of competing claims about the computer's contribution to measured achievement gains. Results suggest achievement gains found in CBI studies are overestimated and are due to uncontrolled but robust instructional methods embedded in CBI…