Alternative Approaches to Addressing Non-Normal Distributions in the Application of IRT Models to Personality Measures.

ABSTRACT: It is generally assumed that the latent trait is normally distributed in the population when estimating logistic item response theory (IRT) model parameters. This assumption requires that the latent trait be fully continuous and the population homogenous (i.e., not a mixture). When this normality assumption is violated, models are misspecified, and item and person parameter estimates are inaccurate. When normality cannot be assumed, it might be appropriate to consider alternative modeling approaches: (a) a zero-inflated mixture, (b) a log-logistic, (c) a Ramsay curve, or (d) a heteroskedastic-skew model. The first 2 models were developed to address modeling problems associated with so-called quasi-continuous or unipolar constructs, which apply only to a subset of the population, or are mea

SUBMITTER: Reise SP 

PROVIDER: S-EPMC6252010 | biostudies-literature | 2018 Jul-Aug

REPOSITORIES: biostudies-literature