OBJECTIVE The goal of this paper was to examine the relationship between methods of acute clinical assessment and measures of secondary cerebral insults in severe traumatic brain injury in children. METHODS Patients who underwent intracranial pressure (ICP), cerebral perfusion pressure (CPP), and brain oxygenation (PbtO(2)) monitoring and who had an initial Glasgow Coma Scale score, Pediatric Trauma Score, Pediatric Index of Mortality 2 score, and CT classification were evaluated. The relationship between these acute clinical scores and secondary cerebral insult measures, including ICP, CPP, PbtO(2), and systemic hypoxia were evaluated using univariate and multivariate analysis. RESULTS The authors found significant associations between individual acute clinical scores and select physiological markers of secondary injury. However, there was a large amount of variability in these results, and none of the scores evaluated predicted each and every insult. Furthermore, a number of physiological measures were not predicted by any of the scores. CONCLUSIONS Although they may guide initial treatment, grading systems used to classify initial injury severity appear to have a limited value in predicting who is at risk for secondary cerebral insults.