Heuristic bias in perception of medical students relating to out-of-hospital cardiac arrests

AIM: The aim of this study was to assess the perceptions of medical students with respect to out-of-hospital cardiac arrests focusing on the frequency and survival and to identify potential problems in resuscitation education. METHODS: Fourth-year medical students in a six-year undergraduate educational system were asked to guess the number of out-of-hospital cardiac arrests with cardiac etiology per year in Japan, related data such as the one-month survival rate from out-of-hospital cardiac arrests with cardiac etiology and the number of deaths from traffic accidents for comparison. The guesses of students were compared with actual statistical data. RESULTS: The incidence of out-of-hospital cardiac arrests was clearly underestimated by the students compared to the real statistics. The median guessed number of out-of-hospital cardiac arrests ranged from 6000 to 20,000 while the real statistics ranged from 73.023 to 78.302 by year (P ​< ​0.001 for all years). In contrast, the guessed number of deaths from traffic accidents was markedly overestimated: the median guessed number ranged from 8000 to 20,000 and the real statistics were 3694 to 4438 (P ​< ​0.001 for all years). The one-month survival rate was also underestimated: the guessed number was 50% and the real rate was 11.5 to 13.5% (P ​< ​0.001 for all years). CONCLUSIONS: Out-of-hospital cardiac arrests are underestimated in frequency, and survival after an arrest is overestimated by medical students. To recognize and to understand the heuristic bias in perception of learners is needed for resuscitation education in addition to promote resuscitation skills of learners.