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Yale-Brown Obsessive Compulsive Scale:
Scoring and Interpretation
The Yale-Brown Obsessive Compulsive Scale (Y-BOCS) is a clinician-rated measure of the severity of obsessive-compulsive symptoms, scored from 0 to 40 across ten severity items (Goodman et al., 1989a). It explains Y-BOCS scoring for the ten core ratings and the two 0 to 20 subtotals, why the symptom checklist stays out of the total, the five severity bands, and how percentage reduction maps onto the consensus definition of response, with code for both SPSS and R.
What the Y-BOCS Measures
The Y-BOCS measures the clinician-rated severity of obsessive-compulsive symptoms, not whether someone has obsessive-compulsive disorder. Goodman and colleagues (1989a) designed its ten severity items to quantify time occupied by symptoms, interference, distress, resistance and control, independently of the particular obsession or compulsion reported.
It is a major outcome measure in OCD intervention studies and specialist clinical services in the United States, and it is especially useful when a clinician needs a standardized baseline and repeated follow-up assessment. The separate symptom checklist assists the interview but is not summed into the 0 to 40 severity total (Goodman et al., 1989a; Stanford Medicine, n.d.). Totals are most often distorted by adding checklist content to the severity sum, and interpretations by applying the original bands to a different version.
Structure of the Y-BOCS
- Items: ten core severity ratings, each scored 0 to 4. Items 1 to 5 assess obsessions and items 6 to 10 assess compulsions.
- Subscales: the obsession and compulsion subtotals each range from 0 to 20.
- Total: one summed score from 0 to 40.
- Reverse-scored items: none among the core severity items.
- Unscored content: the symptom checklist and any optional investigational items must not be inserted into the ten-item total.
- Administration: the original is clinician-administered, usually with a past-week reference period (confirm the exact interview version used). A self-report variant or the Y-BOCS-II needs its own verification, and item numbers here assume the standard original ten-item severity order.
The instrument itself is available from the Stanford Medicine OCD Program and Goodman et al. (1989a).
How to Score the Y-BOCS
- Confirm that the clinician recorded exactly ten core severity ratings coded 0, 1, 2, 3 or 4.
- Sum yb1 to yb5 for ybocs_obs (0 to 20) and yb6 to yb10 for ybocs_comp (0 to 20). Add both for ybocs_total (0 to 40).
- The code applies complete-case scoring: a missing item makes the relevant subtotal missing, and any missing core item makes the total missing. The cited development papers set no general prorating rule.
- For treatment response, calculate the percentage reduction relative to a nonzero baseline as 100 × (baseline − follow-up) / baseline, and specify the response criterion you chose.
COMPUTE ybocs_obs=SUM.5(yb1 TO yb5).
COMPUTE ybocs_comp=SUM.5(yb6 TO yb10).
COMPUTE ybocs_total=SUM.10(yb1 TO yb10).
EXECUTE.data$ybocs_obs <- rowSums(data[paste0("yb",1:5)],na.rm=FALSE)
data$ybocs_comp <- rowSums(data[paste0("yb",6:10)],na.rm=FALSE)
data$ybocs_total <- rowSums(data[paste0("yb",1:10)],na.rm=FALSE)Interpreting Y-BOCS Scores
| Score band | Interpretation |
|---|---|
| 0 to 7 | Subclinical symptoms |
| 8 to 15 | Mild severity |
| 16 to 23 | Moderate severity |
| 24 to 31 | Severe symptoms |
| 32 to 40 | Extreme symptoms |
Source: Goodman et al. (1989a); Stanford Medicine OCD Program (n.d.).
Higher scores represent more severe clinician-rated OCD symptoms. An international expert consensus defines treatment response as a reduction of 35% or more from baseline, partial response as a reduction of 25% to 35%, and remission as a total score of 12 or less (Mataix-Cols et al., 2016). Older trials sometimes used a reduction of 25% or more. Percent reduction is a change indicator, not a diagnostic criterion.
The Y-BOCS quantifies severity among patients assessed for OCD and is not a standalone case-finding diagnosis. Interviewer training and rater reliability matter. Do not transfer the original severity bands to the Y-BOCS-II without validation.
Psychometric Properties
| Property | Published finding | Source |
|---|---|---|
| Internal consistency | Cronbach’s α = .89 in the original evaluation | Goodman et al. (1989a) |
| Interrater reliability | Intraclass correlation .98 for the total score, with high agreement on each item (four raters, 40 patients) | Goodman et al. (1989a) |
| Construct validity | Symptom severity represented independently of obsession or compulsion subtype in the original development | Goodman et al. (1989b) |
| Factor structure | A 544-patient evaluation slightly favored a three-factor solution but recommended continuing the established original two-factor organization | Anholt et al. (2010) |
| Treatment response | A decrease of 35% or more = response; 25% to 35% = partial response; total of 12 or less = remission (consensus definitions) | Mataix-Cols et al. (2016) |
These are source-specific results and cannot be assumed to hold as reliability or accuracy estimates in a new sample.
Using the Y-BOCS in a Study
For longitudinal intervention research, prespecify the Y-BOCS total as a repeated continuous outcome. Linear Mixed Models (Multilevel Modeling) allow unequally spaced visits and adjust for baseline covariates, and clinician or rater effects should be considered if raters vary over time. Because the scale is clinician-rated, agreement between raters can be quantified with Inter-Rater Reliability (Cohen’s Kappa & ICC). Report the mean and standard deviation of total scores, plus absolute and percentage change.
For internal consistency, report the estimate actually observed in the sample, as in Reliability Analysis (Cronbach’s Alpha), rather than quoting a historical number as if it applied to current data. Where response-rate outcomes are used, define the percentage-decrease threshold and state how baseline zeros and missing assessments were handled, drawing on Missing Data Analysis. No universally transferable minimal clinically important difference is established by the original development abstract.
Related field: Clinical Psychology
Reporting the Y-BOCS
Obsessive-compulsive symptom severity was assessed using the clinician-rated Yale-Brown Obsessive Compulsive Scale (Y-BOCS; Goodman et al., 1989a). The ten core items were scored from 0 to 4 and summed to create a total score ranging from 0 to 40, with higher scores indicating more severe symptoms. The obsession and compulsion subtotals were [reported/not reported]. Internal consistency in this sample was [α = XX], and missing values were handled using [method].
References
Anholt, G. E., van Oppen, P., Cath, D. C., Smit, J. H., den Boer, J. A., Verbraak, M. J. P. M., & van Balkom, A. J. L. M. (2010). The Yale-Brown Obsessive-Compulsive Scale: Factor structure of a large sample. Frontiers in Psychiatry, 1, Article 18. https://doi.org/10.3389/fpsyt.2010.00018
Goodman, W. K., Price, L. H., Rasmussen, S. A., Mazure, C., Fleischmann, R. L., Hill, C. L., Heninger, G. R., & Charney, D. S. (1989a). The Yale-Brown Obsessive Compulsive Scale. I. Development, use, and reliability. Archives of General Psychiatry, 46(11), 1006-1011. https://doi.org/10.1001/archpsyc.1989.01810110048007
Goodman, W. K., Price, L. H., Rasmussen, S. A., Mazure, C., Delgado, P., Heninger, G. R., & Charney, D. S. (1989b). The Yale-Brown Obsessive Compulsive Scale. II. Validity. Archives of General Psychiatry, 46(11), 1012-1016. https://doi.org/10.1001/archpsyc.1989.01810110054008
Mataix-Cols, D., Fernández de la Cruz, L., Nordsletten, A. E., Lenhard, F., Isomura, K., & Simpson, H. B. (2016). Towards an international expert consensus for defining treatment response, remission, recovery and relapse in obsessive-compulsive disorder. World Psychiatry, 15(1), 80-81. https://doi.org/10.1002/wps.20299
Stanford Medicine, Obsessive-Compulsive and Related Disorders Program. (n.d.). Diagnosis. https://med.stanford.edu/ocd/about/diagnosis.html
Frequently Asked Questions
Can the Y-BOCS diagnose OCD?
No. Its intended outcome is severity, and an OCD diagnosis requires a separate clinical evaluation.
Is the symptom checklist part of the 0 to 40 score?
No. The ten severity ratings produce the original total, and the checklist supports the interview without entering the sum.
What does a 35% fall in Y-BOCS mean?
It is a commonly used treatment-response definition in controlled studies, conditional on the specified study protocol, and it should be computed against a nonzero baseline.
Can Y-BOCS-II data be analyzed with the same code?
Not without validating that version’s items, response format and scoring documentation.
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