An examination of the validity of EPSCALE using factor analysis.

OBJECTIVE: To examine the validity and utility of the Explanation and Planning Scale (EPSCALE) instrument, a widely used scale for teaching and assessment of explanation and planning skills used by clinicians during the medical interview.

METHODS: Data obtained across 4 OSCE stations during medical student final MB examinations. Exploratory factor analysis, using a single factor and two factor models (based on prior theory) and a six factor empirical model, suggested by parallel analysis.

PARTICIPANTS: 124 medical students sitting final MB examinations at the University of Cambridge.

RESULTS: A single factor model represented a very poor fit. A two factor model with factors labelled 'Explanation' and 'Planning' produced an improved fit, but the best was seen with a six factor model, with factors which broadly corresponded to the domains of the Calgary-Cambridge guide.

CONCLUSIONS: These factor models provide supportive evidence for the construct validity of EPSCALE.

PRACTICE IMPLICATIONS: EPSCALE can justifiably be used in the assessment of shared-decision making skills.