Semantic Interoperability is arguably the least developed aspect of Government Interoperability Frameworks. This could be explained by poor understanding of the semantic interoperability problem in government, considering its substance and scope, difficulties encountered in aligning technical solutions with the practice of government organizations, and the paucity of mature semantic technologies and complete semantic interoperability architectures and solutions (beyond metadata specification and semantic annotation of resources). As a result, most governments prefer to concentrate on technical and organizational aspects of their information sharing and interoperability efforts.

Based on generic requirements posed by information sharing initiatives, analysis of semantic interoperability scenarios in Electronic Government, and emerging semantic interoperability practices, this paper articulates a set of semantic interoperability requirements for Electronic Government considering policy, governance, organizational and technology dimensions. Based on such requirements, it develops a pair of reference models to guide the development of semantic interoperability capabilities for individual agencies involved in collaborations, and for the government as a whole. The paper also discusses how a concrete Semantic Interoperability Architecture (SIA) could be developed from the two reference models.