Purpose. Although physical examination is a fundamental component of medical decision making, relatively few studies have evaluated how physicians quantify clinical signs and whether different methods of assessment have different effects on clinical practice. Objectives. To evaluate a possible impact of clinical experience when attending physicians, medical residents and medical students quantify qualitative signs of physical examination in a teaching hospital. Setting. Hospital das Clínicas, University of São Paulo, Brazil. Subjects. A total of 244 randomly selected physicians and medical students completed a reliable and consistent eight-item questionnaire. Main outcome measures. To compare how they quantified clinical signs of cyanosis, anaemia, jaundice, oedema and dehydration, why they used the method(s) they described, and whether the method used could affect diagnosis, further testing or patient management. A chi-square test was used to calculate differences between the groups. Results. Whilst the majority of those surveyed tended to use a four-level evaluation for these clinical signs, attending staff physicians were more likely to employ two-level evaluations than were residents or medical students. For all five signs, attending physicians' use of dichotomous evaluations was significantly higher than that of residents or medical students: anaemia (P ¼ 0.004), cyanosis (P < 0.001), oedema (P ¼ 0.005), dehydration (P < 0.001) and jaundice (P ¼ 0.002). Conclusion. Although medical students and residents are routinely taught to use a four-level evaluation for these clinical signs, many of those surveyed tend to abandon this experience for a dichotomous approach. Given that the clinicians in this survey tended not to change their initial approach to a patient based on the intensity of this semi-quantitative method, increased emphasis on teaching dichotomous approach evaluations in medical school should be encouraged.