Sackett D.L., "Clinical disagreement: how often it occurs and why", Can Med Assoc J, 1980 Sep 20, 123:499-504] "when three cardiologists interviewed 57 men with chest pain, 54% of the men were judged by at least one clinician to have a history compatible with angina pectoris. However, in only 30% of the 57 patients did all three clinicians agree about the history, and if one of the cardiologists concluded that a given patient had angina pectoris, the other two agreed with him only 55% of the time.