Aim To estimate the cost-effectiveness of diagnostic management strategies for children with minor head injury and identify an optimal strategy.

Methods A probabilistic decision analysis model was developed to estimate the costs and quality-adjusted life years (QALYs) accrued by each of six potential management strategies for minor head injury, including a theoretical ‘zero option’ strategy of discharging all patients home without investigation. The model took a lifetime horizon and the perspective of the National Health Service.

Results The optimal strategy was based on the Children's Head injury Algorithm for the prediction of Important Clinical Events (CHALICE) rule, although the costs and outcomes associated with each strategy were broadly similar.

Conclusions Liberal use of CT scanning based on a high sensitivity decision rule is not only effective but also cost saving, with the CHALICE rule being the optimal strategy, although there is some uncertainty in the results. Incremental changes in the costs and QALYs are very small when all selective CT strategies are compared. The estimated cost of caring for patients with brain injury worsened by delayed treatment is very high compared with the cost of CT scanning. This analysis suggests that all hospitals receiving children with minor head injury should have unrestricted access to CT scanning for use in conjunction with evidence-based guidelines.