Initial evaluation of EPSCALE, a rating scale that assesses the process of explanation and planning in the medical interview

OBJECTIVE: to evaluate the content validity, internal consistency and generalisability of EPSCALE, a new rating scale to measure communication skills in explanation and planning. METHODS: content validity: consensus exercise and expert review. Internal consistency and generalisability: 124 clinical students undertaking 4 OSCE stations with simulated patients, with one observer (hospital specialist, GP or communication specialist) per station, during finals examinations. Internal consistency estimated by coefficient alpha, generalisability estimated by generalisability coefficient and variance components using EPSCALE. RESULTS: content validity was supported by consensus exercise and expert review. Internal consistency was high with a coefficient alpha of greater than 0.8 for all four explanation and planning stations in the finals exam. Generalisability coefficient for 4 OSCE stations was 0.50. CONCLUSIONS: this paper provides initial evidence that EPSCALE has content validity and high internal consistency when used to assess explanation and planning skills in the consultation. It defines the generalisability of this new rating scale. Further work is needed to explore the scale's validity by a range of other measures.