Stability, reliability, and norms for the inventory of interpersonal problems.

Abstract Data were collected on interpersonal functioning that could be used to evaluate therapeutic outcome for individual clients. The Inventory of Interpersonal Problems (IIP) was administered three times over five weeks to undergraduates, none of whom were currently in therapy. Based on selection using an accepted measure of psychological distress (Outcome Questionnaire-45.2; Lambert, 1996), 107 participants were identified as having high psychological distress (high problem) and 172 as having low (low problem) or no (asymptomatic) levels of distress. The high sample was found to be roughly equivalent to a client sample on the IIP. The IIP demonstrated acceptable reliability and stability over five weeks across subsamples, providing potential data for estimating pretherapy baselines. Comparing the low-problem and asymptomatic samples with the high-problem sample provided norms, cut scores, and reliable change indices for interpersonal functioning. Several IIP measures, including distress and each of the quadrant scores, demonstrated adequacy in classification of participants into clinical or nonclinical categories.