1. A method of analysing a process, the method comprising: generating a process template; determining a probabilistic model of the process using a plurality of prior probability distributions, the probabilistic model specifying the process template, wherein the probabilistic model comprises: a plurality of task nodes, the task nodes being nodes for tasks of the process as specified by the process template; a plurality of observables nodes, the observables nodes being nodes for observables that may be caused by performance of the tasks; and a background activities node; wherein one or more of the observables may further be caused by background activities of the background node, and wherein determining the probabilistic model for the process template further comprises specifying at least two of a prior probability distribution for a starting point of the process, a prior probability distribution for each task node, a prior probability distribution for the background activities node, and a prior conditional probability distribution for each of the observables nodes; measuring values of an observable corresponding to one of the observables nodes; and updating a probabilistic estimate of a process state using the measured values.