CORE Outcome Measure CORE-OM
CORE Outcome Measure CORE-OM overview
Creator and Context
The Clinical Outcomes in Routine Evaluation Outcome Measure (CORE-OM) is a 34 item self report measure of psychological distress, designed for routine outcome monitoring in psychological therapy services.
It was developed by Evans, Mellor-Clark, Margison, Barkham, Audin, Connell and McGrath, and launched in 1998. Copyright is held by the CORE System Trust. The CORE instruments are released under a Creative Commons licence that permits software use but is non commercial, so vendors are asked to contact the Trust for written confirmation.
Presenting Conditions
The CORE-OM covers four domains:
Wellbeing (4 items)
Problems and symptoms (12 items)
Functioning (12 items)
Risk (6 items, of which four cover risk to self and two risk to others)
The Trust is candid that the domains were never expected to form neatly separate factors, and that only the Risk domain is reliably separable. Most users do not need domain scores.
Administration
Self completed on paper or in software, taking about 5 to 10 minutes. Each item is rated for the last seven days on a 5 point scale scored 0 to 4. Eight positively cued items are reverse scored.
Desired Audience
Adults in psychological therapy services. The wider CORE family includes CORE-10 and CORE-5 for brevity, GP-CORE for primary care, YP-CORE for young people and LD-CORE for people with learning disabilities.
The CORE-OM is the backbone of routine outcome monitoring in UK psychological therapies. Its distinguishing feature is the risk domain: it is one of the few outcome measures that surfaces risk as part of ordinary session by session data collection rather than as a separate assessment.
Considerations
The four domain structure is psychometrically weak. Do not present the domains as validated subscales.
The risk items behave very differently from the rest of the measure and should be read on their own terms, with a response pathway attached.
Pro rating rules differ by scale. The wellbeing and risk domains must not be pro rated at all.
The instrument may not be modified, and independent translations are a copyright violation.
The licence is non commercial. Software vendors should obtain written confirmation from the CORE System Trust.
How to score the CORE Outcome Measure CORE-OM
Conducting the assessment
The person rates 34 items for the last seven days on a 0 to 4 scale. The score is the mean of completed items.
Interpretation
The clinical score is the mean item score multiplied by 10, giving a range of 0 to 40. Two headline scores are used: all items, and non risk items only.
Connell et al. (2007) derived a clinical cut off of 9.9 on the 0 to 40 scale from a general population sample compared against an aggregated clinical sample, and recommended rounding the cut off to 10.
The CORE System Trust notes that cut off scores must be used thoughtfully and adjusted to fit context and purpose.
Clinical Considerations
Use the total and the non risk score together. A high total driven by risk items means something very different from one driven by symptoms.
Track change against the person's own baseline rather than reading a single score in isolation.
Never collect the risk items digitally without a clear escalation protocol behind them.
CORE Outcome Measure CORE-OM use cases
Session by session outcome monitoring in psychological therapies
Measuring global distress at intake, review and discharge
Surfacing risk within routine data collection
Service level outcome and benchmarking reporting
Category
General Well-being
Research Summary
Evans, C., Mellor-Clark, J., Margison, F., Barkham, M., Audin, K., Connell, J., & McGrath, G. (2000). CORE: Clinical Outcomes in Routine Evaluation. Journal of Mental Health, 9(3), 247 to 255.
Evans, C., Connell, J., Barkham, M., Margison, F., McGrath, G., Mellor-Clark, J., & Audin, K. (2002). Towards a standardised brief outcome measure: Psychometric properties and utility of the CORE-OM. British Journal of Psychiatry, 180(1), 51 to 60.
Connell, J., Barkham, M., Stiles, W. B., Twigg, E., Singleton, N., Evans, O., & Miles, J. N. V. (2007). Distribution of CORE-OM scores in a general population, clinical cut off points and comparison with the CIS-R. British Journal of Psychiatry, 190, 69 to 74.
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Note on Assessment licensing
Some assessments are copyright protected and require a licence or the copyright holder's permission for clinical, commercial or digital use. Where that applies, obtaining and maintaining that permission is the responsibility of the practice or organisation using the assessment. Tacklit provides the digital administration, scoring and reporting. We do not grant, transfer or supply rights to the underlying instrument.
