. Author manuscript; available in PMC: 2010 Aug 16.

Published in final edited form as: Educ Eval Policy Anal. 2009 Nov 1;31(4):480–499. doi: 10.3102/0162373709352239

Table 4. Results of Study-Level and Effect Size-Level Predictors on Achievement Outcomes.

Predictor	N	Grade/Age Comparison	Orthogonal Contrast Coding	B	s.e.	p	R²
Within-Level
Median Grade Retained	N_study = 22 N_ES = 207	---	---	-0.022	0.01	0.102	-0.007
Median Year Post Retention	N_study = 18 N_ES = 147	Grade comparison	---	-0.111	0.04	0.004	-0.128
Median Year Post Retention	N_study = 7 N_ES = 60	Age comparison	---	-0.040	0.02	0.017	0.461
Between-Level
Design Quality	N_study = 22 N_ES = 207	---	c1 (-2/3 1/3 1/3)	0.341	0.05	0.034	0.395
	N_study = 22 N_ES = 207	---	c2 (0 -1/2 1/2)	-0.218	0.15	0.452	0.395

Note: 1) ES = Effect Size; 2) effect sizes at the within level are nested within studies at the between level; 3) R² is the amount of variance explained by the corresponding predictor at the level in which the predictor was entered (see footnote 3 for more information on the calculation of R²).