Table 1.

Categories and proportion of studies for the 48 included articles

Variable	Category	No. of studies (k)	Proportion of studies
Control group types	1. Non-CL	31	.646
	2. CL that did not use computers	11	.229
	3. CSCL that did not use mobile devices	6	.125
Learning outcomesa	1. Learning achievement	39	.661
	2. Learning attitude	13	.220
	3. Peer interaction	7	.119
Learning stage	1. Elementary school	16	.333
	2. Junior high school	3	.063
	3. Senior high school	6	.125
	4. College	17	.354
	5. Teacher	1	.021
	6. Mixed	5	.104
Domain subject	1. Language arts	11	.229
	2. Social studies	6	.125
	3. Science	9	.188
	4. Mathematics	5	.104
	5. Specific abilities	5	.104
	6. Health care programs	4	.083
	7. Finance and economics	1	.021
	8. Education	1	.021
	9. Computer and information technology	3	.063
	10. Engineering projects	3	.063
Group size	0. Not mentioned	9	.188
	1. Dyad	2	.042
	2. Triad	10	.208
	3. Tetrad	6	.125
	4. More than four people	7	.146
	5. Mixed	14	.292
Group composition	0. Not mentioned	27	.563
	1. Homogeneous	4	.083
	2. Heterogeneous	17	.354
Teaching method	1. LT	29	.604
	2. TGT	4	.083
	3. GI	7	.146
	4. Jigsaw	6	.125
	5. STAD	2	.042
Intervention duration	0. Not mentioned	4	.083
	1. ≤4 hours	6	.125
	2. >4 hours and ≤24 hours	0	.000
	3. >1 day and ≤7 days	2	.042
	4. >1 week and ≤4 weeks	16	.333
	5. >4 weeks and ≤6 months	15	.313
	6. >6 months	5	.104
Implementation setting	0. Not mentioned	0	.000
	1. Classroom	35	.729
	2. Museum	1	.021
	3. Outdoors	3	.063
	4. Multiple settings	8	.167
	5. Library	1	.021
Reward method	0. Not mentioned	1	.021
	1. Group rewards for individual learning	4	.083
	2. Group rewards for group outcomes	4	.083
	3. Individual rewards	39	.813

Note. CL = collaborative learning; CSCL = computer-supported collaborative learning; LT = learning together; TGT = team game tournament; GI = group investigation; STAD = student teams achievement division.

^aSome articles included more than one outcome variables.