Application of a psychometric rating model to ordered categories which are scored with successive integers

Abstract

A latent trait measurement model in which ordered response categories are both parameterized and scored with successive integers is investigated and applied to a summated rating or Likert questionnaire. In addition to each category, each item of the questionnaire and each subject are parameterized in the model; and maximum likelihood estimates for these parameters are derived. Among the features of the model which make it attractive for applications to Likert questionnaires is that the total score is a sufficient statistic for a subject’s attitude measure. Thus, the model provides a formalization of a familiar and practical procedure for measuring attitudes.