Are open educational resources (OER) and practices (OEP) effective in improving learning achievement? A meta-analysis and research synthesis

Table 2 Effect of OER on students’ learning achievement

Analysis	N	g	95% CI	Z	p	I²	τ²	Effect size interpretation
Overall	25	0.07	[0.06, 0.09]	10.69	0.001*	96.60	0.04	Negligible
Document	1	− 0.02	[− 0.14, 0.10]	− 0.33	0.744	0	0	Negligible
Interactive (text) book	18	0.13	[0.11, 0.15]	16.48	0.001*	95.86	0.04	Negligible
Interactive materials	5	− 0.11	[− 0.14, − 0.08]	− 7.51	0.001*	94.75	0.06	Negligible
Video	1	0.20	[− 0.33, 0.73]	0.74	0.461	0	0	Small

N = number of studies; g = Hedges’ g effect size; CI = confidence interval; Z = Z value for Hedges’ g, p = p values of Hedges’ g, I² and τ² are measures of effect size variability; *p ≤ 0.001