Bijlage 2: Russell Standard

The criteria

• A 'treated smoker' (TS) is a smoker who undergoes at least one treatment session on or prior to the quit date and sets a firm quit date. Smokers who attend an assessment session but fail to attend thereafter would not be counted. Neither are smokers who have already stopped smoking at the time they first come to the attention of the services.

• A smoker is counted as a 'self-reported 4-week quitter' (SR4WQ) if s/he is a 'treated smoker', is assessed (face to face, by postal questionnaire or by telephone) 4 weeks after the designated quit date (minus 3 days or plus 14 days) and declares that s/he has not smoked even a single puff on a cigarette in the past 2 weeks.

• A smoker is counted as a 'CO-verified 4-week quitter' (4WQ) if s/he is a self-reported 4-week quitter and his/her expired-air CO is assessed 4 weeks after the designated quit date (minus 3 days or plus 14 days) and found to be less than 10ppm.

• A treated smoker is counted as 'lost to follow up at 4-weeks' (LFU4W) if, on attempting to determine the 4-week quitter status s/he cannot be contacted.

• A smoker is counted as a '52-week quitter' (52WQ) if s/he is a 'treated smoker', is assessed (face to face, by postal questionnaire or by telephone) 52 weeks after the designated quit date (plus or minus 30 days) and declares that s/he has not smoked more than 5 cigarettes in the past 50 weeks.

• A treated smoker is counted as 'lost to follow up at 52-weeks' (LFU52W) if, on attempting to determine the 52-week quitter status s/he cannot be contacted.

Calculating success rates

• The 4-week success rate (4WSR) is 4WQ/TS.

• The self-reported 4-week success rate (SR4WSR) is SR4WQ/TS.

• The 52-week success rate (52WSR) is 52WQ/TS.