1. A method of generating a statistical definition defining statistics to be calculated about the behavior of an automated system, said method comprising the steps of: (i) accessing a state/event model of the automated system, the state/event model comprising a plurality of states; (ii) displaying a graphical representation of the state/event model at a user interface, the graphical representation comprising graphical elements representing the plurality of states of the state/event model; (iii) receiving user inputs comprising information to select states from the state/event model to generate a new statistical definition; (iv) displaying at the user interface said newly generated statistical definition using the graphical representation of the state/event model and an additional graphical element, said additional graphical element being arranged such that only a single graphical element is required to represent a selected one of: (a) a virtual transition between two or more states of the state/event model; and (b) a transition between two or more states of the state/event model which are of different objects, wherein said additional graphical element is added to the graphical representation in addition to the graphical elements representing the plurality of states of the state/event model.