Date of Award


Degree Type


Degree Name

Master of Science in Psychology


Clinical Psychology



First Advisor

James O. Prochaska


Most multiple behavior change interventions treat behaviors separately, rather than simultaneously. The present study assessed whether (1) baseline Stage of Change, (2) Effort, and (3) Severity are predictors of singular Action among participants at risk for pairs of behaviors (sun protection &cigarette smoking; high- fat diet &cigarette smoking; high- fat diet & sun protection). Additionally, the study assessed which of the three effects (Stage of Change, Effort, Severity) contributed most to predicting singular Action and examined demographic effects in the context of participants at risk for multiple health behaviors. Pooled data were analyzed (using Logistic Regressions) from three randomized controlled trials (RCTs) for cancer prevention using Transtheoretical Model (TTM) tailored interventions (N = 9,079) that assessed the effectiveness of school, worksite, medical, and home-based prevention programs for multiple cancer risk behavior reduction. The sample was 43.9 years old (SD= 10.7), 90.8% White, and 62.8% female. Analyses included a series of logistic regressions to assess Stage of Change, Effort, and Severity as predictors of health behavior change. Across all 3 behaviors, Stage of change, Effort, and Severity were consistently related to behavior change at 24 months. Interestingly, taking Action on one behavior was related to change on another. For example, among those in the smoking and diet pair, Smoking Habit Strength and Negative Affective Temptations were significant predictors of change on Diet at 24 months. Baseline Sun Pros and Cons were significant predictors of singular Action on Diet. Further, baseline Smoking Severity was related to change on Diet at 24 months. Baseline Sun Severity was related to change on Diet only.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.