Abstract
Despite the frequent use of the Yale–Brown Obsessive–Compulsive Scale–Symptom Checklist (Y‐BOCS‐SC; Goodman et al., 1989a) and the Obsessive–Compulsive Inventory‐Revised (OCI‐R; Foa et al., 2002), there are limited data on the psychometric properties of the two instruments. In the present research, clinician ratings on the Y‐BOCS‐SC for 112 patients with obsessive–compulsive disorder (OCD) were compared to their self‐report ratings on the OCI‐R. In addition, Y‐BOCS‐SC and OCI‐R scores were compared to measures of OCD symptom severity and self‐report measures of anxiety (State–Trait Anxiety Inventory–Trait Subscale [STAI‐T]; Spielberger, Gorusch, & Lushene, 1970) and depression (Beck Depression Inventory‐II [BDI‐II]; Beck, Steer, & Brown, 1996). The six symptom scales of the OCI‐R had good internal consistency reliabilities (αs). For the Y‐BOCS‐SC, three of five scales had good reliabilities (αs >.80), but αs for symmetry/ordering and sexual/religious symptom scales were inadequate. Total scores for the two instruments were strongly correlated with their corresponding “checking” scales, but no individual symptoms scales were identified as indices of overall OCD symptom presence. Scales assessing washing/contamination, symmetry/ordering, and hoarding from the two OCD instruments correlated well, but lower correlations for the other scales suggested differences in symptom coverage by the two instruments. Most symptom scales from the Y‐BOCS‐SC and OCI‐R had low correlations with the BDI‐II and STAI‐T, but the OCI‐R obsessing scale was well correlated (r=.54) with the STAI‐T. These findings reveal some of the strengths and weaknesses of these two OCD instruments, and the results provide guidance for selecting scales that are suitable for measuring OCD symptoms. © 2008 Wiley Periodicals, Inc. J Clin Psychol 64:1–14, 2008.