History-taking is one of the most important clinical skills for the medical student to learn and remains the core component of a doctor's diagnostic 'toolkit'. Yet, it is one of the most difficult clinical skills to assess. Clinical assessment at a trainee intern level has typically focussed on examination skills, and case presentation, which are more easily measured. History-taking is assumed to be of an adequate standard on the basis of the case presentation rather than by direct observation. In this paper we discuss the importance of assessing the patient-doctor encounter directly through observation, in the context of the trainee intern long case examination. Despite changing assessment trends in medical education, these authors argue for the retention of the long case as an assessment tool for final year medical students on the basis of its high face validity and close resemblance to "real life" patient encounters. However, we believe addition of an observing examiner during the history-taking and physical examination augments the inherent value of the longcase and is recommended in order to increase the reliability of the assessment. Observation allows for direct assessment of the student-patient interaction and the hypothetico-deductive approach taken by the student to diagnosis. It provides opportunity to reconcile the multiple interactions occurring between the context and the construct (skills and knowledge) measured in an assessment. Importantly, at a trainee intern level it provides students with a final opportunity to receive feedback on their history taking and diagnostic skills, an integral part of all medical practice, prior to their graduation as junior doctors.