The Reliability and Validity of a Short Form of the Inventory of Interpersonal Problems

Abstract

The Inventory of Interpersonal Problems (IIP) is a 127-item measure designed to assess problems of an interpersonal nature in a clinical setting. As an outcome measure, however, its clinical use is limited due to its length and current trends in therapy research toward multiple, rather than merely pre- and post-, assessments. A shortened form of the Inventory of Interpersonal Problems (IP-S) is proposed to remedy this limitation and to encourage repeated testing over time. This article examines the psychometric properties of the IIP-S as well as its potential as an outcome instrument. High reliability and validity coefficients were found, and the IIP-S was able to distinguish between asymptomatic, community, and outpatient samples. Application of the IIP-S to dose-response research, clinical significance, and the phase model of psychotherapy out-come are also discussed.