Many EMS systems are designed around a model called System Status Management (SSM). It was introduced in the 1980s by Jack Stout as part of the Public Utility Model for EMS systems. SSM has become the most widely accepted management methodology for managing EMS resources. The fundamental concept has two major pieces that shape the lives of the Medics it manages, Dynamic Deployment and Peak Demand Staffing.
Dynamic Deployment becomes utilized once you are already on the shift. Depending on probability trended over time, your unit will be assigned a posting or a place at rest. This location is considered to be in an area where there will be a demand in the immediate to near future. As units are assigned calls and the day progresses, these postings will change with the probability of a need increasing or decreasing for a potential assignment nearby. A truly dynamic system will see the fluid movement of units from posting to posting to ensure the entire area is covered with maximum statistical efficiency.
Peak Demand Staffing requires schedules that put the appropriate number of resources into the system to meet the anticipated demand for those resources. Shifts (referred to as tours by some agencies) in EMS can vary widely depending on where you are in the country, the demands on the system, and the type of agency that you belong to. Your shift can be as short as 4 hours and as long as 24 hours. I haven’t heard of an agency with a 36-hour or 48-hour shift but I wouldn’t be surprised that it exists somewhere.
Demands on the system often dictate the schedule type and shift times for an agency. Agencies in urban centers often see peak call volumes during the “9 to 5” timeframe, when the urban centers are open for business and people are at work. Agencies serving suburban areas may see peak call volumes both before AND after the “9 to 5” timeframe, catching the members of the community before they travel to their workplace in an urban center and after they return home from a typical “9 to 5” job.
 Public Utility Model