The role of preparedness in ambulance dispatching

Response time in the emergency medical service is an important performance measure and ambulance dispatching is one of the most important factors affecting the response time. The most commonly used dispatching rule is to send the closest available unit to the call site. However, though dispatching the closest unit enables the service to achieve the minimal response time for the current call, the response times for the next incoming calls may increase if the area where the closest ambulance is currently located has a high call rate, that is the area becomes ill-prepared. A dispatching algorithm based on the preparedness concept was recently proposed. Rather than greedily minimizing each current response time, the dispatching algorithm takes account of future calls by a quantitative definition of preparedness. This study investigates the role of preparedness by examining the performance of the preparedness-based dispatching algorithm as well as by evolving the algorithm in several ways in order to magnify the effectiveness of preparedness consideration. As a result of these efforts, it is found that the consideration of preparedness in ambulance dispatching can provide significant benefits in reducing response time but only when appropriately used. Journal of the Operational Research Society (2011) 62, 1888-1897. doi:10.1057/jors.2010.145 Published online 3 November 2010