About Us
Contact Us
Team Members
Team Alumni
TTM Measures
The Model
Recommended Articles
Learning Tools
Related Links


Measurement of the process of smoking acquisition among underage adolescents:  Validation of the TTM’s Stages of Smoking Initiation
by Delahanty, Janine C., Ph.D., University of Maryland, Baltimore County, 2005

Cigarette smoking is the single most preventable cause of premature morbidity and mortality in the United States.  Adolescent smoking is typically portrayed as if it were an all-or-nothing phenomenon.  Classifications based solely on the number of days smoked do not capture vulnerable youth who may be thinking about smoking.  Similarly, collapsing across levels of smoking does not provide an accurate picture of the process of initiation of cigarette smoking.     
Three separate studies were conducted to assess the validity of a newly developed measure of the Stages of Smoking Initiation.  Study 1 used data collected from 55,749 underage youth to assess the concurrent validity.  Studies 2 (n = 17,709) and 3 (n = 13,638) used data from underage youth derived from the National Survey on Drug Use and Health (NSDUH).  These youth were classified into one of the 5 Stages of Smoking Initiation:  Precontemplation, Contemplation, Preparation, Action and Maintenance.  Study 2 examined attrition that may affect generalizability while Study 3 examined univariate analyses of covariance to examine differences between the Stages and smoking-related correlates.  The results suggest the Stages of Smoking Initiation are a valid measure of the process of smoking initiation.
Youth who had never smoked and did not express a firm commitment not to smoke in the future (i.e., Contemplation) reported significantly higher mean scores on the smoking-related correlates relative to other non-smoking youth who reported a firm commitment to not smoke in the future (i.e., Precontemplation).  Similarly, youth who were currently smoking at different levels (i.e., experimental vs. regular smoking) differed on the majority of the smoking correlates suggesting that collapsing across levels of smoking into a dichotomous measure loses critical information.  Overall, the relations between the Stages and smoking correlates were stables across school status, gender and ethnicity.  Future research with rigorous longitudinal designs is warranted to further establish the validity of the Stages of Smoking Initiation.  A more sensitive measure of the process of smoking initiation may aid in the design and implementation of more effective prevention interventions.  Preventing adolescents from moving forward in the stages of smoking initiation has the potential for slowing or inhibiting the progression of initiation to regular, maintained cigarette smoking.