The "LFK" index has been promoted as an improved method to detect bias in meta-analysis. Putatively, its performance does not depend on the number of studies in the meta-analysis. We conducted a simulation study, comparing the "LFK" index test to three standard tests for funnel plot asymmetry in settings with smaller or larger…

Publication selection bias undermines the systematic accumulation of evidence. To assess the extent of this problem, we survey over 68,000 meta-analyses containing over 700,000 effect size estimates from medicine (67,386/597,699), environmental sciences (199/12,707), psychology (605/23,563), and economics (327/91,421). Our results indicate that…

In this meta-study, we analyzed 2442 effect sizes from 131 meta-analyses in intelligence research, published from 1984 to 2014, to estimate the average effect size, median power, and evidence for bias. We found that the average effect size in intelligence research was a Pearson's correlation of 0.26, and the median sample size was 60. Furthermore,…

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…

Examining gender differences in learning is of critical importance in terms of revealing any potential inequalities. Although gender differences in lifelong learning tendencies are often examined in individual studies in the literature, the relevant findings are found to be inconsistent. In this study, a meta-analysis was carried out to…

Recently, Picho-Kiroga (2021) published a meta-analysis on the effect of stereotype threat on females. Their conclusion was that the average effect size for stereotype threat studies was d = .28, but that effects are overstated because the majority of studies on stereotype threat in females include methodological characteristics that inflate the…

This meta-analytic review study examined the effects of out-of-school learning (OSL) activities on student attitude and motivation by combining the results of experimental studies conducted between 1990 and 2020. Out of the 1272 studies identified through the literature search, the study selected 46 studies that yielded 47 effect sizes. The effect…

The effect size of psychological counseling based on the Cognitive Behavioral Therapy (CBT) approach on depression and anxiety, was conducted using a meta-analysis method. According to the defined criteria, eight primary studies on anxiety and 21 on depression are included in the meta-analysis. The effect sizes based on a random-effects model are…

As past studies showed mixed results, this meta-analysis determined game-based learning's overall effect on students' critical thinking and tested for moderators, using 21 effect sizes from 20 empirical studies of 1,947 participants. The results showed that game-based learning had a significant positive overall effect on students' critical…

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…

As the empirical literature in educational technology continues to grow, meta-analyses are increasingly being used to synthesise research to inform practice. However, not all meta-analyses are equal. To examine their evolution over the past 30 years, this study systematically analysed the quality of 52 meta-analyses (1988-2017) on educational…

The aim of this research is to analyze the effect of the flipped learning model on the academic success of students. In this research featuring a descriptive survey model, a quantitative research method has been used. While criterion sampling method has been used for selecting the sample of this research, meta-analysis has been used to analyze the…

Results of meta-analyses are potentially valuable for informing environmental policy and practice decisions. However, selective sampling of primary studies through searches exclusively using widely used bibliographic platform(s) could bias estimates of effect sizes. Such search strategies are common in environmental evidence reviews, and if risk…

We explored the possibility of publication bias in the sleep and explicit motor sequence learning literature by applying precision effect test (PET) and precision effect test with standard errors (PEESE) weighted regression analyses to the 88 effect sizes from a recent comprehensive literature review (Pan & Rickard, 2015). Basic PET analysis…

Assessing publication bias is a critical procedure in meta-analyses for rating the synthesized overall evidence. Because statistical tests for publication bias are usually not powerful and only give "P" values that inform either the presence or absence of the bias, examining the asymmetry of funnel plots has been popular to investigate…