Are you currently a smoker?
(For smokers only) In the last year, how many times have you quit smoking for at least 24 hours?
(For smokers only) Are you seriously thinking of quitting smoking?
References
Pallonen, U.E., Velicer, W.F., Prochaska, J.O., Rossi, J.S., Bellis, J.M., Tsoh, J.Y., Migneault, J.P., Smith, N.F., Prokhorov, A.V. (1998). Computer-based smoking cessation interventions in Adolescents: description, feasibility, and six-month follow-up findings. Substance Use & Misuse, 33(4), 935-965.
Stern, R.A., Prochaska, J.O., Velicer, W.F., & Elder, J.P. (1987). Stages of adolescent cigarette smoking acquisition: measurement and sample profiles. Addictive Behaviors, 12, 319-329.