Between Compliance and Complexity: Dispatchers’ Use of an Automatic Emergency Vehicle Assignment System

Decision support systems assist people with tasks that require quick and effective decision making. They are particularly important when decisions must be made in high-stakes and highly complex situations that challenge the human decision-maker. This applies to dispatchers who need to assign emergency responses to medical emergencies. Decision support may improve dispatchers’ performance, thereby possibly saving lives. We analyzed how emergency medical services (EMS) dispatchers use an automatic assignment decision support system to allocate ambulances to medical emergencies based on the characteristics of the event. We show that the event’s complexity affected the dispatchers’ use of the system. Namely, the tendency to use the system decreased when events were more complex. Thus, although a major motivation for introducing decision support systems is to help operators handle increasingly complex scenarios, they tend to use decision support when matters are simple and move to manual choices when the situation becomes more difficult. This pattern should inform the planning and deployment of automation, including system design, operator training, and operational procedures. The findings show that system transparency and user trust are critical factors in the effective deployment of decision support automation.