In sparse data meta-analyses (with few trials or zero events), conventional methods may distort results. Although better-performing one-stage methods have become available in recent years, their implementation remains limited in practice. This study examines the impact of using conventional methods compared to one-stage models by re-analysing…

Introduction: Concerns about the risk of bias (RoB) of Meta-analysis (MAs) have grown in parallel with the exponential increase in the number of publications in science. However, this has not been properly assessed in Education. The aims were to evaluate the RoB of MAs in Education and to identify potential predictors of a lower RoB. Methods:…

As traditionally conceived, publication bias arises from selection operating on a collection of individually unbiased estimates. A canonical form of such selection across studies (SAS) is the preferential publication of affirmative studies (i.e., those with significant, positive estimates) versus nonaffirmative studies (i.e., those with…

In the 2018 meta-analysis of "Educational Psychology Review" entitled "Null effects of perceptual disfluency on learning outcomes in a text-based educational context" by Xie, Zhou, and Liu, we identify some errors and inconsistencies in both the methodological approach and the reported results regarding coding and effect sizes.…

Overlap in meta-reviews results from the use of multiple identical primary studies in similar reviews. It is an important area for research synthesists because overlap indicates the degree to which reviews address the same or different literatures of primary research. Current guidelines to address overlap suggest that assessing and documenting the…

Meta-analysis is a statistical method that combines quantitative findings from previous studies. It has been increasingly used to obtain more credible results in a wide range of scientific fields. Combining the results of relevant studies allows researchers to leverage study similarities while modeling potential sources of between-study…

Research synthesis is the practice of systematically distilling and integrating data from many studies in order to draw more reliable conclusions about a given research issue. When the first edition of "The Handbook of Research Synthesis and Meta-Analysis" was published in 1994, it quickly became the definitive reference for conducting…

Case-mix heterogeneity across studies complicates meta-analyses. As a result of this, treatments that are equally effective on patient subgroups may appear to have different effectiveness on patient populations with different case mix. It is therefore important that meta-analyses be explicit for what patient population they describe the treatment…

Having surveyed the history and methods of meta-regression in a previous paper, in this paper, we review which and how meta-regression methods are applied in recent research syntheses. To do so, we reviewed studies published in 2016 across four leading research synthesis journals: "Psychological Bulletin," the "Journal of Applied…

This study examines meta-analysis studies published in the field of educational sciences from 2010-2019, in journals indexed within the scope of the TÜBITAK ULAKBIM TR Directory. Of the 163 studies scanned, 26 meta-analysis studies that meet the inclusion criteria constitute the sample of this content analysis study. Within this research, a…

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…

This response aims to critically evaluate the methodology and aims of the meta-analytic review written by Maggin and Johnson (2014). The present authors systematically provide responses for each of the original criticisms and highlight concerns regarding Maggin and Johnson's methodology, while objectively describing the current state of evidence…

Based on findings from a large meta-data-based literature survey, this article is intended to provide a comprehensive synthesis of key features of China's music education system as seen through the lens of n = 116 major research studies, drawn from a total of N = 3,257 high-impact Chinese journal articles published during 2007 to 2019. The…

Purpose: The growing public interest in vocational education and training (VET), most recently since the economic crisis of 2007/2008, has led to an exponential increase in articles with a vocational focus, underscoring the need for review studies for the purposes of systematic knowledge aggregation, clarification and interpretation. We assume…

The focus of this article is on the use of theories and on what we imply when we in research claim to use a theory. In this article, diverse uses of one theory will be illustrated with reference to 10 different studies. The aim is not to evaluate or judge how the theory is used in these studies, but to discuss how the diverse uses of one and the…