Being able to analyze all the successive steps of decision making from the first contact with the patient to the final diagnosis is complex because it refers sometimes to intuitive elements proper to each clinician. However, understanding how they integrate probabilities of diseases into their clinical practice and manage diagnostic uncertainties is crucial. This allows a more rational practice of medicine and identifying factors related to the patient, physician or context that may modify the clinical decision making. Furthermore, the use of tools such as clinical scores has taken an important place with the evidence based medicine. Given the fact that they are partly theoretical, it is necessary to assess whether these recommendations are in line with clinical practice.