Contributions to the study of the main Item Response Theory unfolding models with applications in psychology

• Grant number: 18/13997-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2018
• End date: August 31, 2019
• Field of knowledge: Physical Sciences and Mathematics - Probability and Statistics - Statistics
• Principal Investigator: Caio Lucidius Naberezny Azevedo
• Grantee: Marília Gabriela Rocha
• Host Institution: Instituto de Matemática, Estatística e Computação Científica (IMECC). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The present project aims to study the main one-dimensional and parametric Item Response Theory (IRT) unfolding models, providing an appropriate methodological review, discussing aspects such as interpretation, applicability and estimation and implementing them in the computational environment R, through frequentist/Bayesian marginal-profiled methods. As far as we are concerned, there are few packages in the R program, that allow the fitting of such models (even in the excellent mirt package, there are no such types of models). It is intended to consider an application in the psychology field, considering the suitability that the unfolding models have concerning the measurement instruments related to attitude, behavioral aspects and stages of development and re-analysis of Kohlberg's theory of moral development. The theme is of great relevance due to the fact that, while the cumulative models have made great advances in several applications and have developed considerably, the unfolding models did not reach so much progress, due also to the few options in terms of computational programs, to estimate their parameters and discussions about the interpretation of its parameters. The R and GGUM computational programs will be used in the Project.