A brief inventory of Interpersonal Problems-Circumplex using nonparametric item response theory: introducing the IIP-C-IRT.

Nonparametric item response theory methods were applied to the responses of 1,000 college students on the 64 items of the Inventory of Interpersonal Problems-Circumplex (IIP-C; Alden, Wiggins, & Pincus, 1990) to develop an abbreviated 32-item version of the instrument. In a separate validation sample of 981 students, the newly selected scale items did not show evidence of differential item functioning across males and females. There was high convergence found between the new scales and IIP-C parent scales, along with commensurate or improved fits to the circular structural model relative to the full scale and its existing brief derivatives-the IIP-32 and the IIP-SC. Results provide evidence that the new brief scales can improve the level of precision and information yielded in brief assessments of interpersonal problems without gender bias.