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…

Meta-analyses of educational research findings frequently involve statistically dependent effect size estimates. Meta-analysts have often addressed dependence issues using ad hoc approaches that involve modifying the data to conform to the assumptions of models for independent effect size estimates, such as by aggregating estimates to obtain one…

Digital game-based learning (DGBL) interventions can be superior to traditional instruction methods for learning, but previous meta-analyses covered a huge period and included a variety of different target groups, limiting the results' transfer on specific target groups. Therefore, the aim of this meta-analysis is a theory-based examination of…

With increasing canonicity, particularly within higher education assessment, the demonstrable achievement of goals, or the delivery of a program, or as one scholar wryly deemed it, the "manipulation of the independent variable" (Moncher and Prinz 1991, p. 247), are commonly referred to as implementation fidelity or fidelity of…

The partial correlation coefficient (PCC) is used to quantify the linear relationship between two variables while taking into account/controlling for other variables. Researchers frequently synthesize PCCs in a meta-analysis, but two of the assumptions of the common equal-effect and random-effects meta-analysis model are by definition violated.…

Network meta-analysis (NMA) incorporates all available evidence into a general statistical framework for comparing multiple treatments. Standard NMAs make three major assumptions, namely homogeneity, similarity, and consistency, and violating these assumptions threatens an NMA's validity. In this article, we suggest a graphical approach to…

Individual participant data (IPD) meta-analysis projects obtain, harmonise, and synthesise original data from multiple studies. Many IPD meta-analyses of randomised trials are initiated to identify treatment effect modifiers at the individual level, thus requiring statistical modelling of interactions between treatment effect and participant-level…

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…

Tingir et al. (2017) concluded from their meta-analysis that the subject areas taught through mobile devices had significantly higher achievement scores (d = 0.48) than the ones taught with traditional teaching methods. Given the relatively high positive effect of mobile devices on student achievement, we carefully analysed the selected research…

Whether or not to teach grammar explicitly is an issue that has long been debated in the field of SLA. There seems to be a growing consensus among many researchers now in support of embedding some element of explicit instruction within a communicative curriculum. The main arguments in support of explicit instruction are threefold: two widely cited…

This paper presents a critical analysis, from the point of view of a statistician, of the methodology used by Hattie in "Visible Learning," and explains why it must absolutely be called pseudoscience. We first discuss what appears to be the intentions of Hattie's approach. Then we describe the major mistakes in "Visible…

Extensive reading is an approach to language learning that encourages learners to read a large quantity of easy reading material. A substantial body of research confirms the effectiveness of this approach for developing proficiency in both first (L1) and second (L2) languages. This paper explains what extensive reading is, why it is important, and…

Intelligent Tutoring systems (ITSs) and Intelligent Learning Environments (ILEs) have been developed and evaluated over the last 40 years. Recent meta-analyses show that they perform well enough to act as effective classroom assistants under the guidance of a human teacher. Despite this success, they have been criticised as embodying a retrograde…

Previous meta-analyses on peer tutoring have mainly included studies using treatment-control/comparison design and excluded studies that adopted pre-test-post-test design. However, some recent meta-analyses on other interventions adopting pre-test-post-test design revealed that certain crucial intervention moderators should be considered when…

A decade after the publication of Visible Learning: A Synthesis of Over 800 Meta-Analyses Relating to Achievement, the influence of John Hattie's statistical work continues to grow. This paper critically examines one aspect of Hattie's 'synthesis' of education meta-analyses, his summation of research data for whole language literacy teaching. Of…