Evaluation of the effects of a smoking cessation intervention using the multilevel thresholds of change model.

The multilevel thresholds of change model is used to analyze the effect of a smoking cessation intervention on stage of readiness to quit across a 2-year follow-up period. The intervention, targeted to females with high school or less education, consisted of a televised component and a written manual. Any exposure to the intervention had a significant effect on stages that precede quitting but not on quitting; participation in the intervention had significant effects at all levels of change, including quitting. The written component had a stronger independent effect than the televised component. Intervention effects were strongest within women who were initially precontemplative.