Meta-studies are often conducted on empirical findings obtained from overlapping samples. Sample overlap is common in research fields that strongly rely on aggregated observational data (eg, economics and finance), where the same set of data may be used in several studies. More generally, sample overlap tends to occur whenever multiple estimates…

When reporting the results of clinical studies, some researchers may choose the five-number summary (including the sample median, the first and third quartiles, and the minimum and maximum values) rather than the sample mean and standard deviation (SD), particularly for skewed data. For these studies, when included in a meta-analysis, it is often…

Meta-analytic methods are powerful resources to summarize the existing evidence concerning a given research question and are widely used in many academic fields. Meta-analyzes can also be used to study sources of heterogeneity and bias among results, which should be considered to avoid inaccuracies. Many of these sources can be related to study…

We present the R package and web app "statcheck" to automatically detect statistical reporting inconsistencies in primary studies and meta-analyses. Previous research has shown a high prevalence of reported p-values that are inconsistent--meaning a re-calculated p-value, based on the reported test statistic and degrees of freedom, does…

Accurate and consistent reviews of documents describing research studies are essential to valid and generalizable inferences in a meta-analysis. Traditionally a small number of reviewers screen studies using the title, abstract, and possibly the full text to determine a study's eligibility for a meta-analysis. This study explores whether reviewing…

Researchers often seek to synthesize results of multiple studies on the same topic to draw statistical or substantive conclusions and to estimate effect sizes that will inform power analyses for future research. The most popular synthesis approach is meta-analysis. There have been few discussions and applications of other synthesis approaches.…

The present meta-analysis investigated the effects of recasts along with a number of moderating variables on L2 development by meta-analysing the results of 24 primary studies. The findings revealed an overall medium effect size for the effectiveness of recasts (g = 0.70, 95% CI = 0.48-0.93). Furthermore, the findings indicated that recasts are…

This meta-analysis includes experimental and quasi-experimental studies of reading interventions for English learners (ELs) coupled with four specific instructional strategies. The purposes of this meta-analysis were two-fold: (1) to identify the effects of the four instructional strategies (i.e. scaffolding, graphic organizers, interactive read…

Given the widespread use of school-based problem-solving teams (SB PSTs), empirical evidence establishing their effectiveness is essential. Guided by the "Input-Mediator-Output-Input" (IMOI) Framework, this meta-analysis examined SB PST effectiveness generally and differentiated measured effects by targeted outcomes and specific SB PST…

This systematic meta-analytic review investigated the relations between achievement goals and internalizing symptoms and disorders, namely, anxiety and depression. The number of samples for each focal relationship ranged from 3 to 36. The results indicated significant effect sizes for the relations between mastery-approach goals and anxiety (r = -…

This study explores the correlation between technology utilization and language acquisition while analyzing the impact of moderating variables on this relation. Our meta-analysis approach analyzes data from 43 extracts out of 19 primary studies published between 2012 and 2021. Our data analysis employs a random-effect model utilizing a…

Purpose: Research on how much early phonemic awareness (PA) instruction is optimal has produced inconclusive answers. We conducted a nonlinear meta-analysis to estimate the optimal cumulative dosage of early PA instruction on PA outcomes with an associated maximum effect size in preschool through first-grade students. Method: Sixteen experimental…

Purpose: The present meta-analysis investigated the efficacy of anomia treatment in bilingual and multilingual persons with aphasia (BPWAs) by assessing the magnitudes of six anomia treatment outcomes. Three of the treatment outcomes pertained to the "trained language": improvement of trained words (treatment effect [TE]),…

This article comprehensively reviews motor impairments in children with autism spectrum disorder (ASD) to: (1) determine the prevalence of motor problems in children with ASD; (2) understand the nature of motor difficulties in ASD and whether they are consistent with developmental coordination disorder (DCD); and (3) determine if the term DCD was…

This meta-analysis reviews the literature on communication modes, communicative functions, and AAC type examined during interventions with school-age participants with ASD and/or ID who experience CCN. Considering potential differences related to outcomes taught could help identify the most effective means of individualizing AAC interventions. We…