Table 3.

Pooled effects of self-guided stress management programs for unselected college students on target outcomes compared with control groups.

			Effect size			p	Heterogeneity		NNT
		n	g	95% CI	p		I2	95% CI around I2
Overall effects		29	0.19	0.10–0.29	0.000		48	19–66	9.43
Removing two outliers		27	0.23	0.14–0.31	0.000		30	0–56	7.69
Symptom outcomes
Stress		26	0.25	0.15–0.35	0.000		53	28–70	7.14
Anxiety		19	0.11	0.00–0.21	0.045		46	8–69	16.13
Depression		19	0.14	0.03–0.26	0.016		59	33–75	12.82
Only low risk of bias		12	0.17	0.06–0.28	0.003		41	0–70	10.42
Only low and some concerns		23	0.18	0.08–0.29	0.001		54	26–71	9.80
Subgroup analyses
Theoretical background	CBT	3	0.23	−0.06–0.51	0.60	0.41	0	0–80	7.69
	Mind-body	13	0.21	0.05–0.37	0.06		41	0–69	8.47
	Skills training	6	0.07	−0.12–0.26	0.02		61	6–84	25
	TW	7	0.29	0.11–0.46	0.07		48	0–78	6.17
Comparison group	Attention control	12	0.10	−0.03–0.23	0.08	0.11	39	0–69	17.86
	CAU	3	0.16	−0.59–0.90	0.01		78	27–93	11.11
	Waiting list	14	0.28	0.17–0.38	0.19		24	0–60	6.41
Length	Brief	18	0.20	0.08–0.32	<0.01	0.99	53	20–72	8.93
	Moderate	9	0.18	0.00–0.37	0.10		41	0–73	9.80
	Long	2	0.21	−0.26–0.68	0.08		67	0–93	8.47
ITT	Yes	15	0.15	0.04–0.27	<0.01	0.24	56	21–75	11.90
	No	14	0.27	0.11–0.43	0.08		37	0–67	6.58
Recruitment	Campus	11	0.13	−0.07–0.32	<0.01	0.23	58	18–79	13.51
	Mixed	9	0.28	0.20–0.37	0.64		0	0–054	6.41
	Online	6	0.10	−0.09–0.30	0.27		22	0–66	17.86
	Subject pool	3	0.33	−0.06–0.72	0.02		75	17–92	5.43
Format	Online	21	0.18	0.09–0.28	0.02	0.72	43	4–66	9.80
	Other	8	0.24	−0.06–0.53	0.01		62	17–82	7.46
Reminder	Yes	18	0.17	0.07–0.27	0.03	0.47	43	0–67	10.42
	No	11	0.25	0.05–0.46	<0.01		57	16–78	7.14
Compensation	Yes	19	0.13	0.03–0.23	0.06	0.04	36	0–63	13.51
	No	10	0.34	0.16–0.51	0.08		41	0–72	5.26
Risk of bias	High	6	0.26	0.03–0.49	0.02	0.74	12	0–78	6.85
	Some concerns	11	0.21	0.01–0.42	0.04		65	34–82	8.47
	Low	12	0.17	0.06–0.28	0.00		41	0–70	10.42