Table 4

Moderator effects: subgroup analysis (post-test)
Outcome measure Criteria Subgroup (study) n Cohen’s d (95% CI) Test for subgroup differences
Subjective well-being Self-selection Self-selected 15 0.29 (0.18 – 0.39)*** Q=0.64, df=1 (p=.43)
Not self-selected 13 0.38 (0.17 – 0.60)**
Duration <=4 weeks 17 0.35 (0.18 – 0.52)*** Q=1.84, df=2 (p=.91)
<=8 weeks 6 0.24 (0.10 - 0.39)** Slope=0.01, Z=0.14 (p=.89)
>8 weeks 5 0.43 (0.17 – 0.68)**
Type Self help 20 0.33 (0.20 – 0.46)*** Q=0.20, df=2 (p=.91)
Group 5 0.38 (0.03 – 0.73)*
Individual 3 0.41 (0.01 – 0.81)*
Recruitment Community 6 0.29 (0.11 – 0.48)** Q=5.36, df=4 (p=.25)
Internet 2 0.06 (−0.24 – 0.35)ns
Referral/hospital 2 0.51 (0.08 – 0.95)*
University 16 0.36 (0.19 – 0.53)***
Organization 2 0.62 (0.11-1.12)*
Psychosocial problems Specific psychosocial problems 4 0.31 (0.09 – 0.52)** Q=0.10, df=1 (p=.76)
None 24 0.35 (0.22 – 0.48)***
Quality rating Low (1–2) 16 0.29 (0.17 – 0.40)*** Q=2.41, df=2 (p=.30)
Medium (3–4) 11 0.40 (0.19 – 0.61)*** Slope=−0.00, Z=0.08 (p=.94)
High (5–6) 1 0.05 (−0.34 – 0.44)ns
Psychological well-being Self-selection Self-selected 15 0.18 (0.05 – 0.30)** Q=0.32, df=1 (P=.57)
Not self-selected 5 0.25 (0.04- 0.46) *
Duration <=4 weeks 11 0.16 (0.07 – 0.25)*** Q=1.91, df=2 (p=.39)
<=8 weeks 2 0.35 (−0.20 – 0.89)ns Slope=0.05, Z=0.95 (p=.34)
>8 weeks 7 0.41 (0.03 – 0.79)*
Type Self help 10 0.14 (0.05 – 0.23)** Q=3.76, df=2 (p=.15)
Group 6 0.26 (0.08 – 0.44)**
Individual 4 0.81 (−0.01 – 1.63)ns
Recruitment Community 4 0.20 (−0.03 – 0.44)ns Q=7.04, df=4 (p=.13)
Internet 5 0.09 (−0.03 – 0.21)ns
Referral/hospital 4 0.91 (0.24 – 1.57)**
University 5 0.22 (0.08 – 0.35)**
Organization 2 0.18 (−0.43 – 0.78)ns
Psychosocial problems Specific psychosocial problems 5 0.59 (0.00 – 1.18)* Q=1.93, df=1 (p=.17)
None 15 0.17 (0.08 – 0.25)***
Quality rating Low (1–2) 10 0.32 (0.07 – 0.58)* Q=1.86, df=2 (p=.40)
Medium (3–4) 9 0.15 (0.06 – 0.24)** Slope=−0.01, Z=−0.45 (p=.66)
High (5–6) 1 0.29 (−0.11 – 0.68)ns
Depression Self-selection Self-selected 12 0.20 (0.05– 0.36)* Q=1.73, df=1 (p=.19)
Not self-selected 2 0.41 (0.15 – 0.66)**
Duration <=4 weeks 7 0.15 (0.02 - 0.28)* Q=4.86, df=2 (p=.09)
<=8 weeks 2 0.47 (−0.02 - 0.97)ns Slope=0.20, Z=2.32 (p=.02)
>8 weeks 5 0.68 (0.15 – 1.21)*
Type Self help 8 0.15 (0.03 – 0.27)* Q=6.99, df=2 (p=.03)
Group 2 0.47 (−0.02 – 0.97)ns
Individual 4 0.88 (0.29 – 1.47)**
Recruitment Community 1 0.48 (−0.23 – 1.18)ns Q=15.76, df=4 (p<.01)
Internet 5 0.11 (−0.02 – 0.23)ns
Referral/hospital 3 1.14 (0.55 – 1.73)***
University 3 0.41 (0.17 – 0.65)**
Organization 2 0.22 (−0.18 – 0.63)ns
Psychosocial problems Specific psychosocial problems 5 0.78 (0.35 – 1.21)*** Q=7.65, df=1 (p=.01)
None 9 0.16 (0.05 – 0.27)**
Quality rating Low (1–2) 7 0.47 (0.26 – 0.67)*** Q=10.14, df=2 (p=.01)
Medium (3–4) 6 0.15 (0.00 – 0.30)* Slope=−0.10, Z=−2.26 (p=.02)
High (5–6) 1 −0.17 (−0.56 – 0.22)ns

* p<0.05; ** p<0.01; *** p<0.001; ns non-significant.

n = Number of studies.

Bolier et al.

Bolier et al. BMC Public Health 2013 13:119   doi:10.1186/1471-2458-13-119

Open Data