Date of Award


Degree Type


Degree Name

Doctor of Philosophy in Psychology


Clinical Psychology



First Advisor

James O. Prochaska


Background: Human Papillomavirus (HPV) is the most common sexually transmitted disease in the world. It is associated with significant morbidity and mortality in both sexes, accounting for approximately 5% of all cancers worldwide. Receiving the HPV vaccine can substantially reduce the risk of HPV infection and subsequent disease. At this time the majority of Americans reach adulthood without being vaccinated. Increasing HPV vaccination among young adults requires empirical assessment and understanding of HPV-related beliefs and behaviors among this population. To achieve this goal, three studies were conducted.

Study 1: This study examined demographic and psychosocial correlates of HPV vaccination among 834 young adults. HPV vaccination rates in this sample were 73.7% for women and 26.1% for men. Gender comparisons indicated women were more likely to have heard of HPV, received the HPV vaccine, and had higher HPV-related knowledge. Health-care providers and mothers were common sources of vaccine recommendation among men and women. Those who identified as white and/or Hispanic and participants with health insurance were most likely to have received the vaccine. Other predictors of vaccination included higher HPV-related knowledge and perceived responsibility for HPV prevention. These findings underscore several important demographic and psychosocial factors associated with HPV vaccination.

Study 2: This study developed and validated measures of the Transtheoretical Model of Change constructs Stage of Change, Decisional Balance, and Self-Efficacy in young adult men (N = 329). The stage distribution was: Precontemplation 54.1%, Contemplation 14.6%, Preparation 5.2%, and Action/Maintenance 26.1%. Principal Components Analysis (PCA) performed on a split half sample revealed a 2-factor solution for the Decisional Balance scale, representing both Pros (α = 0.78) and Cons (α = 0.83). For the Self-Efficacy scale, PCA revealed a single-factor solution (α = 0.83). Confirmatory Factor Analysis (CFA) confirmed that the two-factor uncorrelated model for Decisional Balance χ2 (35) = 82.6, p < .001, CFI = .92, GFI = .92, AASR - .06, and a single factor model for Self-Efficacy χ2 (14) = 43.4, p < .001, CFI = .93, GFI = .92, AASR = .04. Follow-up ANOVAs supported the theoretically predicted relationships between Stage of Change, Pros, and Self-Efficacy. Overall, these results support the validity of these TTM measures for HPV vaccination among young adult men and provide the foundation for an intervention to promote vaccine acquisition.

Study 3: This study examined gender invariance for measures of Decisional Balance and Self-Efficacy for HPV vaccination using data collected from 329 men and 505 women. The original measures were developed in Study 2 and in past research. Structural equation modeling was used to test for factorial invariance. Pattern Identity Invariance was a good fit for the Decisional Balance measure.The highest level of invariance, Strong Factorial, was a very good fit for Self-Efficacy. Evidence of Pattern Identity and Strong Factorial invariance for Decisional Balance and Self-Efficacy, respectively, indicate that measures of the latent constructs Decisional Balance and Self-Efficacy are the same across male and female subgroups. These measures will yield meaningful comparisons of men and women in future research and clinical applications.



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