A zero- and K-inflated mixture model for health questionnaire data

作者：Finkelman Matthew D^*; Green Jennifer Greif; Gruberc Michael J; Zaslavsky Alan M

来源：Statistics in Medicine, 2011, 30(9): 1028-1043.

DOI：10.1002/sim.4217

• item response theory
• mixture model
• WHO composite international diagnostic interview (CIDI)
• oppositional defiant disorder
• conduct disorder

In psychiatric assessment, Item Response Theory (IRT) is a popular tool to formalize the relation between the severity of a disorder and the associated responses to questionnaire items. Practitioners of IRT sometimes make the assumption of normally distributed severities within a population; while convenient, this assumption is often violated when measuring psychiatric disorders. Specifically, there may be a sizable group of respondents whose answers place them at an extreme of the latent trait spectrum. In this article, a zero-and K-inflated mixture model is developed to account for the presence of such respondents. The model is fitted using an expectation-maximization (E-M) algorithm to estimate the percentage of the population at each end of the continuum, concurrently analyzing the remaining 'graded component' via IRT. A method to perform factor analysis for only the graded component is introduced. In assessments of oppositional defiant disorder and conduct disorder, the zero-and K-inflated model exhibited better fit than the standard IRT model.

• 出版日期2011-4-30