Table 3.

Effect size analysis for primary learning outcomes.

Outcome variable	k	N	Hedges’ g	95% CI	SE	Z	p	I 2	τ 2	Q
Vocabulary learning overall	44	3,789	0.72***	[0.58, 0.86]	0.071	10.14	<0.001	52.0%	0.089	89.67***
Word recognition	41	3,456	0.68***	[0.53, 0.83]	0.076	8.95	<0.001	48.2%	0.082	79.23***
Vocabulary output	38	3,178	0.76***	[0.59, 0.93]	0.087	8.74	<0.001	56.4%	0.095	84.86***
Lexical depth	23	1,967	0.71***	[0.49, 0.93]	0.112	6.34	<0.001	61.8%	0.117	57.62***
Metacognitive strategy	42	3,547	0.68***	[0.52, 0.84]	0.082	8.29	<0.001	55.7%	0.093	92.54***
Metacognitive knowledge	38	3,201	0.71***	[0.53, 0.89]	0.092	7.72	<0.001	58.3%	0.105	88.76***
Metacognitive monitoring	35	2,876	0.66***	[0.48, 0.84]	0.092	7.17	<0.001	52.9%	0.089	72.24***
Metacognitive regulation	32	2,634	0.65***	[0.45, 0.85]	0.102	6.37	<0.001	59.6%	0.108	76.73***
Learning persistence	31	2,654	0.64***	[0.47, 0.81]	0.087	7.36	<0.001	49.8%	0.078	59.84***

k = number of studies; N = total sample size; SE = standard error; ***p < 0.001.