The article by Dissmann and Le Clerc¹ is a welcome addition to the prehospital literature. However, it is important to remind readers that the observation that doctors do not prolong prehospital on-scene times within their system is simply that: an observation.

All observational studies are influenced by bias, confounding and the play of chance, and in this study there were a number of confounding variables that could have significantly influenced scene times. These include severity of injury, degree of entrapment, resources at scene, interventions before arrival of the helicopter, and the training and experience of the helicopter crew. Without robust case mix adjustment, the true effect of the presence of a doctor on the “on-scene time” cannot be properly established. The validity of the conclusion …