Table 2.

Overall mean ES summary and test for heterogeneity.

				Homogeneity test			Tau-squared			Test of null (2-tailed)
k	N	Hedges' g	95% CI	Q(g)	p	I 2	Tau2	SE	Tau	Z	p
12	640	0.998	[.549,1.446]	123.147	0.000	91.068	0.526	0.345	0.725	4.367	0.000

K, number of effect sizes; CI, confidence interval.