Many tests have been developed to assess OCD. The most cited test is the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). The YBOCS consists of 10 questions that are administered by a clinician in an interview format. The answers are rated on a five-point scale, and scores can range from 0 to 40, with a possible 20 points coming from both the obsession section and the other 20 possible points coming from the compulsion section. The higher the score, the more severe the OCD. Typically, a score of 16 or higher is considered the cutoff for research studies on OCD, so that would be considered a moderate level of OCD. The Y-BOCS also has a 102-item checklist that when administered can review many different subsets of OCD, including the following examples of obsessions and compulsions: contamination, safety, religion, symmetry, hoarding, cleaning, checking, arranging, counting, and confessing.
Other tests may include the Padua Inventory, the Maudsley Obsessional Compulsive Inventory, and the Obsessive Compulsive Inventory. For a full review of the above tests and others for the assessment of OCD, you can consult the Practitioner’s Guide to Empirically Based Measures of Anxiety (Antony, Orsillo, and Roemer, 2001).