The present invention relates to a method of creating a data model for analysis of operations relating to services and to a method for analyzing such a data model. The operations involve parameters, and each operation has at least one input parameter and at least one output parameter. In the a data model there are nodes representing the parameters and directed relations representing the operations, and a directed relation representing an operation connects at least one node representing said at least one input parameter of the operation to at least one node representing said at least one output parameter of the operation. Computer programs and computers for creating or analyzing services using the described data model are also discussed.