Andrich, David2011-01-292011-01-291978Andrich, David. (1978). Application of a psychometric rating model to ordered categories which are scored with successive integers. Applied Psychological Measurement, 2, 581-594. doi:10.1177/014662167800200413doi:10.1177/014662167800200413https://hdl.handle.net/11299/99456A 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.enArticle