This paper addresses the problem of identifying redundant data in large-scale service-oriented information systems. Specifically, the paper puts forward an automated method to pinpoint potentially redundant data attributes from a given collection of semantically-annotated Web service interfaces. The key idea is to construct a service network to represent all input and output dependencies between data attributes and operations captured in the service interfaces, and to apply centrality measures from network theory in order to quantify the degree to which an attribute belongs to a given subsystem. The proposed method was tested on a federated governmental information system consisting of 58 independently-maintained information systems providing altogether about 1000 service operations described in WSDL. The accuracy of the method is evaluated in terms of precision and recall. Categories and Subject Descriptors D.2.8 [Software Engineering]: Metrics; D.2.12 [Software Engineering]: Intero...