Table 1.

Methodological quality of included studies with stage based interventions aimed at smoking cessation

Reference	Methodological quality*	1. Randomisation	2. Concealment of allocation	3. Blinding of participants	4. Blinding of outcome assessors	5. Blinding of care providers	6. Baseline comparability	6a. Adjustment for baseline differences	7. Completeness of follow up	8. Inclusion criteria	9. Point estimates and variability	10. Drop outs (intention to treat)	11. Description of statistical methods	12. Sample size calculation	13. Comparability of treatment	14. Stage of change assessed at baseline	15. Stage of change instrument validated	16. Interventions tailored	17. Quality of implementation	18. Details of training reported
Berman et al 1995w1	4/13	Yes	Not stated	Not stated	Not stated	No	Not stated	Not stated	No	Yes	No	No	Yes	Not stated	Yes	Yes	Not stated	Partial	Yes	Not stated
Butler et al 1999w2	9/13	Yes	Yes	Not stated	Yes	No	Yes	Not applicable	No	Yes	Yes	Yes	Yes	Yes	No	Yes	Not stated	Yes	Not stated	Yes
Cornuz et al 2002w3	12/13	Yes	Yes	Yes	Yes	Yes	Yes	Not applicable	No	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Not stated	Yes	Yes	Yes
DiClemente et al 1991w4	5/13	Yes	Not stated	Not stated	Not stated	No	No	No	Yes	Yes	No	No	Yes	No	Yes	Yes	Yes	Yes	No	Yes
Dijkstra et al 1999w5	6/11	Not stated	Not stated	Not applicable	Not stated	Not applicable	No	Yes	Yes	Yes	No	Yes	Yes	Not stated	Yes	Yes	Not stated	Yes	Not stated	Not applicable
Emmons et al 2001w6	9/13	Yes	Yes	No	Not stated	No	Yes	Not applicable	Yes	Yes	No	Yes	Yes	Yes	Yes	Yes	Not stated	Yes	No	Yes
Etter and Perneger 2001w7	9/13	Yes	Not stated	No	Not stated	Not applicable	Yes	Not applicable	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Not applicable
Gritz et al 1993w8	3/13	Not stated	Not stated	Not stated	Not stated	No	Not stated	No	No	Yes	No	Yes	Yes	Not stated	No	Yes	Not stated	Partial	Yes	Yes
Lennox et al 1998w9	8/13	Not stated	Yes	Yes	Not stated	No	No	Yes	No	Yes	Yes	No	Yes	Yes	Yes	Yes	Yes	Health professionals	Yes	Yes
Lennox et al 2001w10	7/13	Yes	Not stated	Not stated	Not stated	Not stated	No	Yes	No	Yes	No	Yes	Yes	Yes	Yes	Yes	Not stated	Yes	Yes	Not applicable
Morgan et al 1996w11	5/13	Not stated	Not stated	Not stated	Not stated	No	No	No	Yes	Yes	No	Yes	Yes	Not stated	Yes	Not stated	Not stated	Yes	Yes	Yes
Pallonen et al 1994w12	2/12	Not stated	Not stated	Not applicable	Not stated	No	Not stated	Not stated	No	Yes	No	No	Yes	No	No	Yes	Not stated	Yes	Yes	Not stated
Pallonen et al 1998w13	6/12	Yes	Not stated	Not stated	Not stated	Not applicable	Yes	Not applicable	No	Yes	Yes	No	Yes	Not stated	Yes	Yes	Not stated	Yes	Yes	Not applicable
Pieterse et al 2001w14	8/13	Yes	No	Yes	Not stated	Not stated	No	Yes	No	Yes	Yes	Yes	Yes	No	Yes	Yes	Not stated	Yes	Yes	Yes
Pletsch 2002w15	6/13	No	Not stated	Not stated	Not stated	Not stated	Yes	Not applicable	Yes	Yes	Yes	No	Yes	No	Yes	Yes	Not stated	Yes	No	No
Prochaska et al 2001w16	5/13	Not stated	Not stated	Not stated	Not stated	Not applicable	Yes	Not applicable	No	Yes	No	Yes	Yes	No	Yes	Yes	Not stated	Yes	No	Not applicable
Prochaska et al 2001w17	5/13	Not stated	Not stated	Not stated	Not stated	Not stated	Yes	Not applicable	No	Yes	No	Yes	Yes	No	Yes	Yes	Not stated	Yes	No	Not applicable
Reeve et al 2000w18	3/13	Not stated	Not stated	Not stated	Not stated	Not stated	Not stated	No	No	Yes	No	No	Yes	No	Yes	Yes	Not stated	Yes	No	No
Resnicow et al 1997w19	7/13	Not stated	Not stated	Not stated	Not stated	No	No	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes	Yes	Not stated	Yes	Yes	Yes
Sinclair et al 1999w20	3/13	Not stated	Not stated	Not stated	Not stated	No	Not stated	Not stated	Yes	Yes	No	Not stated	Not stated	Not stated	Yes	Not stated	Not stated	Yes	Yes	Yes
Stotts et al 2002w21	6/13	Yes	Yes	Not stated	Not stated	Not stated	No	Yes	No	Yes	No	No	Yes	No	Yes	Yes	Not stated	Yes	Yes	Yes
Tappin et al 2000w22 w24	8/13	Yes	Yes	Not stated	Not stated	Not stated	Yes	Not applicable	Yes	Yes	No	Yes	Yes	No	Yes	Yes	Not stated	Yes	Yes	Yes
Wang 1994w23	6/13	Not stated	Not stated	Not stated	Not stated	No	Yes	Not applicable	Yes	Yes	Yes	Not stated	Yes	Not stated	Yes	Yes	Not stated	Health professionals	Not stated	Yes

^*Maximum score for the 13 items is 11 or 12 if blinding of care providers, participants, or both not applicable. Quality assessment was carried out, using an existing quality assessment tool by one reviewer and checked by a second, using following predefined criteria: 1. method of intervention allocation reported; 2. intervention allocation concealed; 3. participants blind to existence of other conditions (scored as “not applicable” if group receiving no intervention at all was included; then blinding considered not possible); 4. outcome assessors blinded to intervention allocation; 5. care providers or educators blind to existence of other conditions (not applicable if intervention did not involve educators); 6. groups similar at baseline (if not similar, 6a. were analyses adjusted for these differences); 7. last follow up includes 80% or more of randomised participants; 8. eligibility criteria specified; 9. point estimates and measure of variability presented for primary outcome measure (behaviour change); 10. intention to treat analysis used or differences between drop outs and patients who completed trial explained; 11. statistical methods described; 12. calculation of statistical power or required sample size reported; 13. groups treated identical other than named interventions (scored as “yes” unless clear that contamination of interventions may have been present); 14. participants' stage of change assessed before intervention; 15. stages of change instrument validated; 16. interventions tailored to individual stage of change (yes, partial (for example, only booster sessions stage matched), intervention aimed at health professionals including some data on participants); 17. quality of implementation recorded; 18. details of training of people giving intervention reported where applicable.