Evidence-based assessment/Instruments/Yale-Brown Obsessive Compulsive Scale

The Yale–Brown Obsessive Compulsive Scale (Y-BOCS) is a test to rate the severity of obsessive–compulsive disorder (OCD) symptoms.

The scale, which was designed by Wayne K. Goodman and his colleagues, is used extensively in research and clinical practice to both determine severity of OCD and to monitor improvement during treatment. This scale, which measures obsessions separately from compulsions, specifically measures the severity of symptoms of obsessive–compulsive disorder without being biased towards the type of content of obsessions or compulsions present.

Scoring
The scale is a clinician-rated, 10-item scale, each item rated from 0 (no symptoms) to 4 (extreme symptoms), yielding a total possible score range from 0 to 40. The scale includes questions about the amount of time the patient spends on obsessions, how much impairment or distress they experience, and how much resistance and control they have over these thoughts. The same types of questions are asked about compulsions (e.g., time spent, interference, etc.) as well. The results can be interpreted based on the total score: Patients scoring in the mild range or higher are likely experiencing a significant negative impact on their quality of life and should consider professional help in alleviating obsessive–compulsive symptoms.
 * 0–7 is sub-clinical;
 * 8–15 is mild;
 * 16–23 is moderate;
 * 24–31 is severe;
 * 32–40 is extreme.

A self-rated version of the Yale-Brown Obsessive-Compulsive Scale has been developed. The self-report and clinician-administered versions of the Y-BOCS are correlated to each other.

Studies have been conducted by members of the Iranian Journal Of Psychiatry & Clinical Psychology to determine the accuracy of the Yale–Brown Obsessive Compulsive Scale (specifically as it appears in its Persian format). The members applied the scale to a group of individuals and, after ensuring a normal distribution of data, a series of reliability tests were performed. According to the journal, "[the] results supported satisfactory validity and reliability of translated form of Yale-Brown Obsessive-Compulsive Scale for research and clinical diagnostic applications".

Children's Version
The children's version of the Y-BOCS, or the Children's Yale–Brown Obsessive Compulsive Scales (CY-BOCS), is a clinician-report questionnaire designed to assess symptoms of obsessive compulsive disorder from childhood through early adolescence.

The CY-BOCS contains 70 questions and takes about 15–25 minutes. Each question is designed to ask about symptoms of obsessive compulsive behavior, though the exact breakdown of questions is unknown. For each question, children rate the degree to which the question applies on a scale of 0-4. Based on research, this assessment has been found to be statistically valid and reliable.

Question breakdown, scoring, and interpretation
The 0-4 scale is broken down as follows: Interpretation
 * 0: none
 * 1: mild
 * 2: moderate
 * 3: severe
 * 4: extreme

While there is not and exact breakdown of scoring for neither the child report nor the parent report, it can be assumed that the higher the overall score on the test, the more severe the OCD. The following subscores can be used as a tentative reference: Note that these subscales only suggest these levels of severity.
 * 0-7: subclinical severity of symptoms
 * 8-15: mild symptoms
 * 16-23: moderate symptoms
 * 24-31: severe symptoms
 * 32-40: extreme symptoms