1. A computer program product for generating a process model, the computer program product comprising a computer readable storage medium having computer readable program code embodied therewith, said computer readable program code being executable by a computer to: extract data associated with a process execution trace of a running process and extract any prior knowledge data relating to said running process; calculate at least one transition confidence parameter for said prior knowledge data; identify any existing process models relating to said running process; generate a confidence trace bias for any said existing process model identified; calculate an enhanced bias value by combining said confidence trace bias value and value of said transition confidence parameter; and generate a learned process model by using as input said extracted process execution trace data, said prior knowledge data, said identified existing model and said enhanced bias value.