Predicting the utilization of helicopter emergency medical services: an approach based on need.

Accurately predicting the utilization of helicopter emergency medical services is critical to both resource allocation and fiscal integrity, and health planning agencies may insist that the need for such services be demonstrated before the system can become operational. Most utilization predictions have been based solely on the experience of other services despite wide variation in need and use. This kind of prediction has the serious disadvantage of not considering local demographics and individual system variations. A better method uses needs analysis to predict utilization and to calculate demand. This method is based on a systematic identification of conditions that will benefit significantly from helicopter transport to a referral center, the incidence of those conditions, and the population to be served. The need for service is estimated by multiplying the population by the incidence. The fraction of patients with demonstrated need who will actually use the service is estimated on the basis of the interaction between local characteristics and condition variables.