Modeling intention of HPV vaccination by means of a class of mixture models for ordinal data

Aim of the paper is to deal by means of a mixture model for the analysis of rating data several psychological factors which influence the decision process of vaccination achieved by mothers for their 12-year-old daughters. The psychological theoretical framework is the Health Action Process Approach (HAPA) model, which allows to investigate goal intention considering risk perception, outcome expectation, and self-efficacy. Specifically, the study intends to explore how these psychological factors plus knowledge, socio-demographic characteristics (job, religion, political orientation, education), and common practices contribute to develop the process of intention expressed on a Likert scale with m = 5 categories to the human papillomavirus (HPV) vaccine among mothers. By means of a sampling of 507 mothers, we analyze the level of intention performing a useful framework for data based on a discrete probabilistic model which takes into account both the discrete nature of the observed realizations and the composite nature of the score elicitation mechanism. Conclusion and interpretation are discussed.