Does the tool maintain its prediction power in a new sample of patients?
Again, the researchers did not develop a prediction tool to study in a new group of patients. The study would likely be valid in this same tertiary pediatric hospital setting, as the authors performed a comprehensive study, accepting all pediatric patients with severe traumatic brain injury with GCS < 9. A repeat study would then presumably include the same patient population. However, particularly given the small sample size, such a validation study is certainly indicated. The authors mentioned strict management of ICP and CPP as per their institutional protocol. This protocol may contain minor yet potentially significant differences when compared to other pediatric intensive care units' management of elevated ICP. These management differences may have an impact on the outcomes of pediatric STBI and thus reproducibility of this study in other institutions (3,4). In addition even at the authors' hospital, the protocol has changed during the five years of this study, which may have an i
