Abstract: A method of operating a data processing system to monitor conforming events generated by an event generating system is disclosed. The method includes storing lists of workflow definitions and active workflow instances. Each workflow definition includes a plurality of phase definitions, each phase definition includes a list of event types that start and terminate that phase. Each active workflow instance conforms to one of the workflow definitions and includes a list of active phase instances for that active workflow instance. Conforming events are processed by terminating an active phase instance if the conforming event corresponds to an event that terminates that active phase instance, by starting a new active phase instance if the conforming event corresponds to an event that starts a phase corresponding to one of the workflow instances, and by recording the conforming event and all active phase instances that were started or terminated by the conforming event.