Description:
There is evidence that the major anxiety and depressive disorders could reflect a single underlying internalization factor. For a group of 1,031 clinic-referred children, the study examined support for this factor, and used the two-parameter logistic model to examine the item response theory properties of the disorders in this factor. For the set of anxiety and depressive disorders, confirmatory factor analysis supported a one-factor model. The two-parameter logistic model analysis indicated that all the internalizing disorders in this factor were strong discriminators of the internalizing dimension. Also, they measured more of the internalizing dimension and with more precision in the upper half of the trait continuum. There was also support for the convergent validity of the internalizing dimension, in that it had large-to-medium effect size correlations with internalizing scores of other measures. The implications of the findings for clinical practice and clinical classification are discussed.
Description:
The graded response model, which is based on item response theory, was used to evaluate the psychometric properties of adult self-ratings (N = 852) of the attention deficit/hyperactivity disorder inattention, hyperactivity, and impulsivity symptoms presented in the Current Symptoms Scale. This scale has four ordered response categories. The results for the discrimination parameters showed that all symptoms were generally good for discriminating their respective latent traits. For virtually all symptoms, their threshold values showed that they were especially good at representing the appropriate traits from around the mean trait level onward. The item information function values for most symptoms indicated reasonable reliability from approximately the mean trait level onward. All these findings are new and extend existing psychometric information for adult self-ratings of the attention deficit/hyperactivity disorder symptoms in the Current Symptoms Scale.