An apparatus and method are disclosed for analysing a process. An exemplary method includes: generating a process template; and determining a probabilistic model specifying the process template. The method can include use of task nodes for tasks of the process; observables nodes for observables that may be caused by performance of the tasks; and a background activities node, wherein observables may further be caused by background activities of the background node. The method can include use of task nodes for tasks of the process; observables nodes for observables that may be caused by performance of the tasks; and a background activities node, observables may further be caused by background activities of the background node. The method can include measuring values of an observable corresponding to one of the observables nodes; and updating a probabilistic estimate of the process state using the measured values.