Towards a standardised brief outcome measure: Psychometric properties and utility of the CORE–OM

TLDR

A standardised outcome measure is needed across psychological therapy disciplines to assess efficacy and effectiveness. The study presents psychometric data on reliability, validity, and sensitivity to change for the CORE–OM. The authors developed a 34‑item self‑report CORE–OM covering well‑being, symptoms, function, and risk, and assessed its internal and test–retest reliability, demographic differences, factor structure, correlations with other instruments, and sensitivity to change. The CORE–OM showed good internal and test–retest reliability (0.75–0.95), strong convergent validity with seven instruments, marked differences between clinical and non‑clinical samples, and good sensitivity to change, making it a reliable, valid, and widely acceptable measure.

Abstract

Background An acceptable, standardised outcome measure to assess efficacy and effectiveness is needed across multiple disciplines offering psychological therapies. Aims To present psychometric data on reliability, validity and sensitivity to change for the CORE–OM (Clinical Outcomes in Routine Evaluation – Outcome Measure). Method A 34-item self-report instrument was developed, with domains of subjective well-being, symptoms, function and risk. Analysis includes internal reliability, test–retest reliability, socio-demographic differences, exploratory principal-component analysis, correlations with other instruments, differences between clinical and non-clinical samples and assessment of change within a clinical group. Results Internal and test–retest reliability were good (0.75–0.95), as was convergent validity with seven other instruments, with large differences between clinical and non-clinical samples and good sensitivity to change. Conclusions The CORE–OM is a reliable and valid instrument with good sensitivity to change. It is acceptable in a wide range of practice settings.