THE RELIABILITY AND VALIDITY OF A SHORT-FORM OF THE INVENTORY OF INTERPERSONAL PROBLEMS

The Inventory of Interpersonal Problems (IIP) is a 127-item measure de signed to assess problems of an interpersonal nature in a clinical set ting. 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 th e Inventory of Interpersonal Problems (IIP-S) is proposed to remedy th is limitation and to encourage repeated testing over time. This articl e examines the psychometric properties of the IIP-S as well as its pot ential as an outcome instrument. High reliability and validity coeffic ients were found, and the IIP-S was able to distinguish between asympt omatic, community, and outpatient samples. Application of the IIP-S to dose-response research, clinical significance, and the phase model of psychotherapy outcome are also discussed.