Does observation add to the validity of the long case?

A London medical school final MBBS examination for 155 candidates.

To investigate whether observing the student-patient interaction in a history taking (HT) long case adds incremental information to the traditional presentation component.

A prospective study of a HT long case which included both examiner observation of the student-patient interview (Part 1) and traditional presentation to different examiners (Part 2). Checklist and global ratings of both parts were compared. Examiners were paired to estimate inter-rater reliability. The students also took a 20 station Objective Structured Clinical Examination (OSCE).

Correlation of (I) examiner ratings for observation and presentation of the HT long case (II) examiner pair ratings and (III) stepwise regression analysis of scores for the HT long case with OSCE scores.

Seventy-five (48.4%) candidates had two examiner pairs marking their case history. Observation and presentation scores correlated poorly (checklist 0.38 and global 0.33). Checklist and global scores for each part correlated at higher levels (observation 0.64 and presentation 0.61). Inter-rater reliability correlations were higher for observation (checklist 0.72 and global 0.71) than for presentation (checklist 0.38 and global 0.60). When HT long case scores were correlated with OSCE scores, using stepwise regression, global presentation scores showed the highest correlation with the OSCE score (0.36) and the global observation score contributed a further 12% to the correlation (0.50).

Observation of history taking in a long case appears to measure a useful and distinct component of clinical competence over and above the contribution made by the presentation.