To determine the effects of explicit instruction (EI) and potential moderators in second/foreign language (L2) teaching, this study meta-analyzed 28 primary reports (a total of 67 unique samples, N = 3754). The main results show that EI was significantly effective in facilitating L2 development, with effect sizes ranging from moderate to large…

Meta-analysis of diagnostic test accuracy (DTA) is a powerful statistical method for synthesizing and evaluating the diagnostic capacity of medical tests and has been extensively used by clinical physicians and healthcare decision-makers. However, publication bias (PB) threatens the validity of meta-analysis of DTA. Some statistical methods have…

Content-based techniques for credibility assessment (Criteria-Based Content Analysis [CBCA], Reality Monitoring [RM]) have been shown to distinguish between experience-based and fabricated statements in previous meta-analyses. New simulations raised the question whether these results are reliable revealing that using meta-analytic methods on…

Systematic reviews and meta-analyses are essential for drawing conclusions regarding etiologic associations between exposures or interventions and health outcomes. Observational studies comprise a substantive source of the evidence base. One major threat to their validity is residual confounding, which may occur when component studies adjust for…

A best-evidence synthesis and meta-analysis were conducted to evaluate interventions designed to decrease noncompliance in early childhood settings. Studies were examined for quality, intervention components, and outcomes for young children (ages 2-8 years) across settings. Results indicated most designs were high-quality and produced desired…

Meta-analytical methods face particular challenges in research fields such as social and political research, where studies often rest primarily on qualitative and case study research. In such contexts, where research findings are less standardized and amenable to structured synthesis, the case survey method has been proposed as a means of data…

Introduction: The What Works Clearinghouse (WWC) reviews rigorous research on educational interventions with a goal of identifying "what works" and making that information accessible to educators and policymakers. The WWC has historically prioritized internal validity over external validity in rating the quality of research. One critique…

A central principle of programmatic assessment is that the final decision is not a surprise to the learner. To achieve this, assessments must demonstrate predictive and consequential validity, however, to date, research has only focussed on the former. The present study attempts to address this gap by examining the predictive and consequential…

Selective publication and reporting in individual papers compromise the scientific record, but are meta-analyses as compromised as their constituent studies? We systematically sampled 63 meta-analyses (each comprising at least 40 studies) in "PLoS One," top medical journals, top psychology journals, and Metalab, an online, open-data…

Network meta-analysis has played an important role in evidence-based medicine for assessing the comparative effectiveness of multiple available treatments. The prediction interval has been one of the standard outputs in recent network meta-analysis as an effective measure that enables simultaneous assessment of uncertainties in treatment effects…

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…

Rigorous evidence identification is essential for systematic reviews and meta-analyses (evidence syntheses) because the sample selection of relevant studies determines a review's outcome, validity, and explanatory power. Yet, the search systems allowing access to this evidence provide varying levels of precision, recall, and reproducibility and…

Early-childhood researchers and practitioners have become increasingly aware that schools must integrate social and emotional learning outcomes into curricula and instruction to maximize children's learning and well-being. Behavioral regulation, which falls under the broader self-management social and emotional learning competency, has been linked…

Randomized controlled trials are a special case of designs using an unbiased instrument to take care of confounders even if they are unmeasured or unknown. Another example of studies using instrumental variables is the Mendelian experiment and Directed Acyclic Graphs show the power of such designs to enhance the internal validity. It is argued…

This meta-analysis examined the ecological and population validity of intervention research for students with low mathematics achievement (SWLMA). Forty-four studies published between 2005 and 2019 that met the inclusionary criterion were included in this analysis. Our findings suggest, to improve the external validity and generalizability of…