Table 2.

Overall effect sizes, homogeneity, and moderator analyses

Measure	k	n	d+	95% Confidence intervals		Homogeneity analysis
				Lower	Upper	Qw	Qb
Overall	17	7,446	0.33	0.23	0.43	41.55***
Outliers							0.23
Excluding Anthonisen et al. (1994)	16	3,521	0.31	0.20	0.42	29.92*
Quality							3.10
Adequate power and sample sizea	9	6,833	0.37	0.27	0.48	26.7***
Inadequate power and sample sizea	8	613	0.22	0.00	0.43	7.28
Intervention designb							0.26
Drug versus placebo	4	1,417	0.31	0.21	0.42	2.61
Intervention versus usual care	12	5,996	0.34	0.20	0.48	33.84***
Setting							13.34***
Home component	11	2,666	0.28	0.19	0.37	24.01**
Exclusively medical setting	6	4,780	0.46	0.37	0.55	2.94
Deliveryc							49.77***
Group components	4	4,749	0.49	0.34	0.64	6.07
One-to-one only	12	2,606	0.26	0.14	0.38	11.86
Medication							26.23***
SSM	7	5,736	0.42	0.37	0.48	12.83*
No SSM	10	1,710	0.32	0.13	0.50	26.48**
Outcome							3.58
PP	6	1,133	0.29	0.00	0.57	9.11
CA	11	6,313	0.42	0.36	0.48	24.02**
BM1 ‘Provide information on the health consequences of smoking and smoking cessation’							1.87
Present	8	6,350	0.36	0.21	0.50	27.01***
Absent	9	1,096	0.27	0.11	0.44	7.29
BM2 ‘Boost motivation and self-efficacy’							7.29**
Present	12	2,940	0.30	0.21	0.39	26.43**
Absent	5	4,506	0.43	0.21	0.65	5.54
BM3 ‘Provide feedback on current behaviour and progress’							1.06
Present	5	4,668	0.35	0.11	0.59	16.26**
Absent	12	2,778	0.30	0.19	0.41	11.91
BM4 ‘Provide rewards contingent on successfully stopping smoking’							0.66
Present	3	853	0.38	0.24	0.52	0.37
Absent	14	6,593	0.32	0.19	0.44	41.03***
BM6 ‘Prompt commitment from the client there and then’							0.14
Present	3	742	0.36	0.22	0.51	1.49
Absent	14	6,704	0.33	0.21	0.45	39.69***
BM7 ‘Provide rewards contingent on effort or progress’							2.03
Present	3	634	0.42	0.05	0.79	7.45*
Absent	14	6,812	0.30	0.20	0.41	31.59**
BM9 ‘Conduct motivational interviewing’							0.04
Present	4	412	0.34	−0.06	0.74	5.59
Absent	13	7,034	0.36	0.29	0.44	33.89***
BM10 ‘Identify reasons for wanting and not wanting to stop smoking’							2.78
Present	4	543	0.21	0.04	0.39	1.52
Absent	13	6,903	0.36	0.23	0.48	34.89***
BS1 ‘Facilitate barrier identification and problem-solving’							3.00
Present	7	2,177	0.28	0.11	0.46	23.45***
Absent	10	5,269	0.37	0.26	0.48	13.92
BS2 ‘Facilitate relapse prevention and coping’							0.17
Present	11	6,556	0.33	0.23	0.43	34.4***
Absent	6	890	0.36	0.14	0.59	6.72
BS3 ‘Facilitate action planning/develop treatment plan’							4.72*
Present	7	5,057	0.44	0.39	0.50	11.71
Absent	10	2,389	0.33	0.17	0.50	24.19**
BS4 ‘Facilitate goal setting’							0.17
Present	10	6,552	0.31	0.18	0.44	36.79***
Absent	7	894	0.34	0.20	0.49	3.59
BS5 ‘Prompt review of goals’							1.08
Present	4	1,028	0.28	0.14	0.43	4.25
Absent	13	6,418	0.35	0.23	0.48	34.17***
BS6 ‘Prompt self-recording’							4.83*
Present	5	4,962	0.40	0.22	0.57	16.10**
Absent	12	2,484	0.29	0.15	0.42	13.86
BS8 ‘Advise on environmental restructuring’							0.14
Present	3	742	0.36	0.22	0.51	1.49
Absent	14	6,704	0.33	0.21	0.45	39.69***
BS13 ‘Advise on methods of weight control’							33.48***
Present	3	4,539	0.53	0.37	0.69	4.35
Absent	14	2,907	0.25	0.15	0.36	13.42
A1 ‘Advise on stop smoking medication’							0.67
Present	10	6,593	0.35	0.23	0.47	29.27***
Absent	7	853	0.29	0.09	0.49	6.61
A2 ‘Advise on/facilitate use of social support’							8.00**
Present	7	5,372	0.40	0.23	0.57	13.40*
Absent	10	2,074	0.25	0.11	0.39	7.99
A3 ‘Adopt appropriate local procedures to enable clients to obtain free medication’							0.15
Present	7	5,256	0.37	0.28	0.45	15.73*
Absent	10	2,190	0.35	0.20	0.51	24.21**
A4 ‘Ask about experiences of stop smoking medication that the smoker is using’							3.45
Present	3	4,608	0.40	0.25	0.56	3.82
Absent	14	2,838	0.31	0.18	0.43	28.12**
A5 ‘Give options for additional and later support’							0
Present	8	5,787	0.36	0.28	0.44	21.82**
Absent	9	1,659	0.36	0.19	0.54	18.98*
RD1 ‘Tailor interactions appropriately’							3.43
Present	10	6,498	0.37	0.20	0.54	31.53***
Absent	7	948	0.24	0.11	0.37	3.23
RD2 ‘Emphasize choice’							3.48
Present	6	5,445	0.41	0.33	0.48	10.99
Absent	11	2,001	0.31	0.14	0.47	26.23**
RI1 ‘Assess current and past smoking behaviour’							0.03
Present	11	6,114	0.36	0.27	0.45	29.39**
Absent	6	1,332	0.35	0.12	0.57	7.27
RI2 ‘Assess current readiness and ability to quit’							0.04
Present	8	5,300	0.35	0.25	0.45	16.25*
Absent	9	2,146	0.36	0.21	0.51	21.94**
RI3 ‘Assess past history of quit attempts’							1.39
Present	3	774	0.26	0.05	0.48	3.90
Absent	14	6,672	0.35	0.23	0.46	35.83***
RI5 ‘Assess nicotine dependence’							9.12**
Present	5	1,242	0.19	0.07	0.31	4.17
Absent	12	6,204	0.39	0.27	0.51	23.67*
RI7 ‘Assess attitudes to smoking’							2.50
Present	3	485	0.21	0.03	0.39	1.47
Absent	14	6,961	0.36	0.24	0.47	35.22***
RI10 ‘Assess physiological and mental functioning’							0.71
Present	4	4,274	0.37	−0.04	0.78	11.50**
Absent	13	3,172	0.33	0.26	0.40	23.24*
RC1 ‘Build general rapport’							0.17
Present	4	4,410	0.32	0.14	0.50	9.15*
Absent	13	3,036	0.34	0.21	0.46	26.83**
RC4 ‘Explain expectations regarding treatment programme’							2.07
Present	4	4,641	0.39	0.26	0.53	5.55
Absent	13	2,805	0.32	0.19	0.44	27.34**
RC5 ‘Offer/direct towards appropriate written materials’							0.28
Present	9	5,872	0.41	0.36	0.46	21.77***
Absent	8	1,574	0.38	0.19	0.58	19.58**
RC6 ‘Provide information on withdrawal symptoms’							2.41
Present	6	1,535	0.39	0.24	0.54	12.75*
Absent	11	5,911	0.30	0.16	0.44	28.78**
RC8 ‘Elicit client views’							0.36
Present	5	1,042	0.31	0.19	0.43	3.93
Absent	12	6,404	0.35	0.22	0.49	34.87***
COPD medication advice							0.02
Present	4	247	0.37	−0.03	0.76	5.82
Absent	13	7,199	0.35	0.26	0.43	34.44***
COPD-specific information							1.35
Present	7	1,489	0.35	0.11	0.59	23.61***
Absent	10	5,957	0.42	0.37	0.47	16.15
Link between COPD and smoking							8.42**
Present	4	4,524	0.45	0.39	0.51	6.11
Absent	13	2,922	0.31	0.18	0.45	28.92**
BS ‘Specific focus on behaviour, maximizing self-regulatory capacity/skills’							1.13
Present	13	7,190	0.32	0.23	0.42	38.92***
Absent	4	256	0.46	0.18	0.75	2.50
A ‘Promote adjuvant activities’							0.89
Present	13	7,169	0.33	0.24	0.42	38.72***
Absent	4	277	0.45	0.14	0.76	2.79

Note. SSM = stop smoking medication.

^aDefined as power >0.5 and sample size ≥35 in each cell (Coyne et al., 2010)

^bOne study compared two active conditions

^ck = 15 Wilson et al., excluded as their experimental groups compared individual and group support.

^*Significant at p < .05

^**significant at p < .01

^***significant at p < .001.