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, wherein the source systems are sub-systems of the communications network and provide subscribers of the communications network their subscribed services, said source systems comprising one or more of a billing system, a network management system of a telecommunications network, and a customer relationship management system; defining rules of processing the data received from each of the source systems; generating, in a distributed manner, independently and without customer involvement, on the basis of the rules, at least one customer experience event of the communications network; determining, before the received data shows that the customer experience has been affected, the generated customer experience event to exceed a threshold that indicates a future 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.