This paper reports on a field study into the nature of decision making in the command and control of emergency ambulances at the London Ambulance Service (LAS). This paper will describe how real-time decisions are made by emergency medical dispatchers and the decision strategies they invoke as they assess the situation, plan and co-ordinate the dispatch of emergency ambulances.
A cognitive task analysis approach known as the Critical Decision Method (Hoffman et al., 1998; Klein et al., 1989) was used in the study. The study showed that decision making in emergency ambulance command and control involves four major processes---assessment of the situation, assessment of resources, planning, and co-ordinating and control. These four processes function within an awareness of goings-on in and around the sectors that the dispatchers operate in. This awareness is referred to as situation awareness and is being reported elsewhere (Wong & Blandford, submitted). The decision making process resembles the decision making described by naturalistic decision making models (see (Zsambok & Klein, 1997) for an extensive discussion on the topic) and is an extension of the Integrated Decision Model (Wong, 1999). The study also suggested that a lot of effort was directed at understanding and assessing the situation and in maintaining a constant awareness of the situation. These observations have significant implications for the design of information systems for command and control purposes. These implications will be discussed separately in another paper.
The paper will first introduce the domain of EMD at the LAS, then explain how the Critical Decision Method was used in the data collection and in the data anlaysis. It will then describe how decisions are made, particularly during major incidents, and then discuss the implications of those findings for the design of command and control systems.
