“…7,11,12,23,24 These studies, largely relying on multi-institution databases, have demonstrated that helicopter transport when compared with ground transport is protective against mortality. 7,8,11,12,32 In the second iteration of our multivariable model, where we included ISS, RTS, and highest AIS, we found the same results. Risk adjustment is necessary to reduce the confounding caused by patients with minor injuries who are likely to be transported only by ground and, thus, would otherwise make it appear that ground transport protects against mortality.…”