TY - JOUR AU - Freund, Yonathan AU - Philippon, Anne-Laure PY - 2017 DA - 2017/01/13 TI - External validation of a clinical decision rule: we need events in a population in order to rule them out! JO - Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine SP - 3 VL - 25 IS - 1 AB - We respond to the Lorton et al. article on external validation of the PECARN study. With an event rate of only 0.6%, we believe that their study failed to confirm the safety of this rule. Such a low number of events should call for caution when interpreting the results of diagnostic tests. SN - 1757-7241 UR - https://doi.org/10.1186/s13049-016-0346-9 DO - 10.1186/s13049-016-0346-9 ID - Freund2017 ER -