Anne Fleur Kortekaas-Rijlaarsdam

35 MPH AND ACADEMIC PERFORMANCE: META-ANALYSIS 2 Publication Bias Inspection of Egger funnel plots for publication bias indicated no asymmetry for math productivity, reading accuracy and reading attempted. Egger’s test was significant for math accuracy indicating a risk for publication bias. Fail-safe n values indicated that the effects of MPH on math accuracy, math productivity and reading attempted were quite robust, whereas the effect of MPH on reading accuracy was not robust (Table 1). There was no significant relation between sample size and effect size for any of the dependent variables entered in the meta-analysis. Therefore, it is unlikely that publication bias meaningfully influenced results, with the exception of MPH effects on reading accuracy. Risk of bias of individual studies according to the Cochrane index for cross-over trials was generally low, for details see supplementary Table E2.3. Mediation and Moderation None of the potential mediators or moderators significantly interacted with the effects of MPH on math accuracy or productivity (all p s>.09). Supplementary Table E2.4 reports on the number of studies included in the meta-regression, Z-values, 95% CI and p-values. Figure 2.2 Forest plot of the effects of MPH on math accuracy