Bains 2000.

Methods	Country: Canada Setting: four counties in Eastern Ontario; entrants to a 1995 Q&W contest in 2 counties (Frontenac, Lennox and Addington), and a random sample of non‐entrant smokers from all 4 counties (Frontenac, Lennox and Addington, Hastings, Prince Edward). Design: Quasi‐randomized; Intervention group were all entrants to the Q&W contest; controls were selected by random telephone dialling (full details obtained from authors).
Participants	616 participants (231 Intervention, 385 Control). All had to be 18+, daily smokers of at least 10 cpd. Baseline differences: Intervention group higher % female (59.4% vs 54%), younger, more highly educated, more likely to be employed, more likely to be in a professional or semi‐professional job. Significant differences also in average cpd, average years smoking, quit attempts in past year, number of smoking friends, working in a smoke‐free workplace, number of smoking co‐workers, and stage of change.
Interventions	1. Intervention: entry into a locally publicized Q&W contest. ‘Quit Kit' supplied to each entrant (letter of encouragement, cessation info, list of local cessation programmes, tips on maintenance, fridge magnet with health unit info phone number). Winners were entered into a lottery draw with a grand prize of C$1000 and secondary prizes of lesser values. 2. Control: no cessation support, only baseline and 1‐year telephone interview
Outcomes	Contest winners (smoke‐free for month prior to the draw) not biochemically validated; verification was from ‘buddy' testimony. Unvalidated self‐report of 6 months continuous abstinence at 1‐year follow‐up. Stage of change.
Notes	Quit rates were not reported as ITT, but it is possible to discern these from the paper. Originally in Q&W.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Intervention group were all entrants to the Q&W contest; controls were selected by random telephone dialling. Therefore, a sequence was not generated and the intervention group were self‐selected. Members of the intervention group, compared with the random survey group, were younger, more highly educated, more likely to be employed, more likely to be working as a semi‐professional or professional, had fewer friends or co‐workers who smoked and more often worked in a smoke‐free environment. In order to be eligible to win the Q&W contest, respondents had to be smoke‐free in the month before its conclusion. As a result, a very high proportion of the intervention group (87%) were actively trying to quit at the time of the baseline interview. Thus the intervention group were more likely to be in the action or preparation stages of change.
Allocation concealment (selection bias)	High risk	Intervention group were all entrants to the Q&W contest; controls were selected by random telephone dialling. Therefore, the intervention group was self‐selected.
Blinding of outcome assessment (detection bias) All outcomes	High risk	No biochemical validation (a ‘buddy' was used for verification).
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: “Of those recruited at baseline, 86.5% (n = 200) of the intervention group were re‐contacted successfully after one year using a follow‐up telephone call, and 84.4% (n = 325) of the random survey group were re‐contacted.” Therefore, follow‐up rates were high and comparable between trial conditions.