1. A method comprising: receiving data from a plurality of source systems in a communications network, said source systems encoding data according to different data models; defining rules of processing the data received from each of the source systems; generating, on the basis of the rules, at least one customer experience event of the communications network; determining the generated customer experience event to exceed a threshold that indicates a degraded service for a subscriber; determining a network element originating the generated customer experience event; and controlling the determined network element or a controller of the determined network element.