Progress in the technology of measurement: Applications of item response models

Despite advances in psychometric theory and analytic techniques, a number o f issues regarding the assessment of depression remain unresolved, includin g the relative effectiveness of response options (option effectiveness), th e ability of existing measures to detect differences in depressive severity (scale discriminability), and the extent to which certain groups of indivi duals use items and options differently (differential item functioning). On e part of the article introduces the fundamentals of nonparametric item res ponse models; the 2nd part of the article illustrates how item response mod els can be applied to address specific psychometric issues. Although the ar ticle focuses on the assessment of depression, the problems addressed in th is article are present in virtually every field of psychological research, and the techniques offered may be applied broadly. Analytic techniques base d on item response models are not only helpful in identifying and ultimatel y resolving many of these issues, they are essential to ensure that traits, abilities, and conditions, such as depression, are assessed fairly and equ itably.