Effect sizes across studies show substantial heterogeneity, with wide prediction intervals spanning large negative to large positive true effects¶

Claim · All claims
Evidence · 1 study · quant-synthesis r2 · q3
Currency · newest study 2026 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q3 i? The Q-statistic was significant and I-squared was 83.78% in the model with outliers, indicating most observed variance reflects true heterogeneity. → Ellinor Waaland 2026 q3 i? The 95% prediction interval ranged from -0.96 to 1.90, indicating future true effects could range from large negative to large positive. → Ellinor Waaland 2026

Evidence¶

Ellinor Waaland 2026¶

Ellinor Waaland, Vibeke Rønneberg, Dieuwer ten Braak. (2026). Effects and Characteristics of Mathematics Interventions for Students with Co-Occurring Difficulties in Mathematics and Reading: A Systematic Review with Meta-Analysis. Educational Psychology Review. https://doi.org/10.1007/s10648-026-10184-x

q3 · i? · quant-synthesis · r2

Heterogeneity assessment in the CHE meta-analysis of 60 effect sizes nested in nine studies. The Q-test was significant; the article reports "The I-squared value of 83.78 indicates that 83.78% of the variance in observed effects between effect sizes within studies reflects true heterogeneity" and a prediction interval from -0.96 to 1.90.

"The Q-statistic for the test of heterogeneity in effect sizes across studies was significant (Q (59) = 1015.47, p < 0.001)."

Discussion¶

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