Table 4. Outcomes of the meta-analysis collapsed across feature match condition on transfer and the feature moderator analysis.

		All features											Feature moderator analysis
		Intervention effects								Heterogeneity
Feature category	Transfer feature	k	N	n	d	SE	95% CI	z	p	Q	I2	p	R2	p
Stimulus type
	Digits	13	22	985	0.619	0.139	0.347–0.892	4.459	< .001	67.416	76.267	< .001	0.490	0.003
	Letters	7	19	478	0.306	0.099	0.113–0.500	3.111	0.002	7.774	9.953	0.353	0.000	0.163
	Words/nonwords	11	22	597	0.361	0.134	0.098–0.623	2.660	0.007	24.006	58.344	0.008	0.090	0.362
	Objects	4	24	221	0.468	0.137	0.200–0.737	3.420	0.001	1.015	0.000	0.908	0.000	0.543
	Spatial location	161	36	810	0.516	0.125	0.271–0.761	4.122	< .001	61.205	70.591	< .001	0.020	0.462
Stimulus domain
	Verbal	23	62	1185	0.370	0.070	0.232–0.508	5.253	< .001	36.101	33.521	0.054	0.690	0.004
	Visuo-spatial	16	51	912	0.531	0.111	0.314–0.748	4.798	< .001	44.425	61.733	< .001	0.090	0.401
Stimulus modality
	Auditory	13	27	759	0.416	0.094	0.231–0.601	4.408	< .001	20.478	36.517	0.084	0.400	0.134
	Visual
Response modality
	Spoken	14	31	738	0.422	0.094	0.238–0.607	4.486	< .001	19.732	34.118	0.102	0.080	0.482
Serial recall
	Verbal	14	20	814	0.371	0.093	0.189–0.554	3.985	< .001	22.742	38.439	< .001	0.830	0.044
	Visuo-spatial	14	20	826	0.732	0.18	0.380–1.084	4.076	< .001	82.633	81.847	< .001	0.530	< .001
	All	16	40	910	0.445	0.081	0.286–0.604	5.471	< .001	95.801	63.466	< .001	0.560	< .001
Complex span
	Verbal	12	19	407	0.263	0.117	.034–0.492	2.253	0.024	29.541	55.994	0.005	0.870	0.002
	Visuo-spatial	9	20	447	0.390	0.132	0.130–0.650	2.942	0.003	17.892	49.698	0.036	1.000	< .001
	All	15	43	859	0.320	0.083	0.157–0.483	3.854	< .001	60.968	55.715	< .001	0.290	0.021
Backward span
	Verbal	10	10	559	0.579	0.146	0.294–0.865	3.973	< .001	24.252	62.889	0.004	0.800	0.025
	All	11	13	620	0.724	0.146	0.438–1.010	4.961	< .001	44.09	72.783	< .001	0.41	0.026

k = number of studies; N = number of effect sizes; n = number of participants.