The level of commitment in the analysis of clinical errors made in the emergency department (ED) is currently focused on organization and processes rather than on individual action. Four major cases of clinical errors made in the ED of a teaching hospital were investigated. Analysis suggested that the process of clinical decision making and the overreliance on the use of patterns during the cognitive process had a major role in causing the errors, rather than factors related to procedures or organization. It appears hard to design system changes and tactics to significantly reduce the probability of making errors associated with the cognitive process involved in clinical decision making. The authors have initiated a systematic analysis of errors made during the diagnostic workup in their ED, and the rate of clinically significant errors is tracked. A file is being created with the purpose to use it for teaching and orientation of all new staff.