Distribution of CORE-OM scores in a general population, clinical cut-off points and comparison with the CIS-R.

Background: Although measures of psychopathology are designed for use in clinical populations, their meaning derives from comparison with normal populations.

Aims: To compare the distribution of scores on the Clinical Outcomes in Routine Evaluation-Outcome Measure (CORE-OM) from a general population sample with the distribution in an aggregated clinical sample to derive recommended cut-off points for determining clinical significance.

Method: The CORE-OM general population sample was based on a weighted subsample of participants in the psychiatric morbidity follow-up survey who completed valid CORE-OM forms following their interview (effective n=535).

Results: Comparison of the CORE-OM general population sample with a clinical sample aggregated from previous studies (n=10761) yielded a cut-off score of 9.9 on the 0-40 scale of the CORE-OM. The CORE-OM was highly correlated (r=0.77) with the Clinical Interview Schedule-Revised, supporting convergent validity.

Conclusions: We recommend rounding the CORE-OM cut-off score to 10. However, cut-off scores must be used thoughtfully and adjusted to fit context and purpose.