The signal-bearing medium of claim 23 whereby multiple service delivery models are available for retrieval, wherein the particular service delivery model chosen for retrieval is chosen using a state-space method, wherein a collection of values that each service variable will assume during a service delivery event define a state, and wherein each service delivery model is associated with a space of possible values each service variable may assume, the operations further comprising:

choosing a service delivery model for retrieval that is associated with a space of service variable values which encompasses the state defined by the collection of values that each service variable will assume during the service delivery event.