1. A computer-implemented method of managing a process, said computer implemented method comprising: identifying activities that comprise the process, wherein the process is a series of activities, wherein an input of at least one subsequent activity is dependent on an output of at least one previous activity; identifying drivers associated with at least one metric, reflecting an efficiency of said process, for each of the activities; identifying, in a computer, bridge variables from said identified drivers, wherein each bridge variable is a driver that is relevant to more than one of said activities; establishing, in a computer, a relationship between various drivers by representing at least one non-bridge variable driver in terms of one or more of said bridge variables; using said relationship, representing activities at least as a function of one or more of said bridge variables, thereby reflecting interdependence between said activities to represent the entire series of activities of said process, in a computer; generating, in a computer, a model of said process at least as a function of said bridge variables by combining representations of activities comprising said process; and outputting, from said model in a computer, a predictive metric reflecting an efficiency of the total process.