For PND and SMTE analyses the overall mean effect sizes fell into the "questionably effective" to "fairly effective" classification.
The overall mean effect sizes for five outcomes are presented in Table 2.
Mean effect sizes for mathematics and reading data were identical (both equal to 0.38).
Weighted mean effect sizes based on single site studies were generally larger than effect sizes computed based on analysis of the overall multi-site sample.
Independent raters coded participant characteristics, design and methodological features, intervention content, and calculated weighted mean effect sizes using fixed and random-effects models.
Small mean effect sizes that are not always robust to controls: providing information to parents and improving school management and supervision.
We found significant overall mean effect sizes for mathematics d ¯ math * = 0.38, reading d ¯ reading * = 0.38, and science d ¯ science * = 0.43, all of which are moderate in magnitude.
Statistically significant weighted mean effect sizes favored native test takers in mathematics d ¯ math * = 0.38, reading d ¯ reading * = 0.38, and science d ¯ science * = 0.43.
However, for seven studies with a PE-design it was possible to calculate an overall ES: the weighted mean effect sizes ranged from.45 (internalized problem behavior) to.60 (externalizing problem behavior; behavior problems in general).
In healthy participants, the mean effect size for aerobic exercise was moderate (dthr = .41, dint = .59), while the mean effect sizes for isometric exercise (dthr = 1.02, dint = .72) and dynamic resistance exercise (dthr = .83, dint = .75) were large.
Weighted mean effect sizes (and number of subjects needed for 80% power at α=0.05) were computed based on the individual single site studies as well as on the overall multi-site study.
