Absract: Problem statement: One of the challenges of e-gov systems is to provide, during a search process, relevant services that meet user expectations. Indeed, obtaining relevant information responding to user queries is a difficult process. It becomes even complex when the query terms have many meanings and do not fit with the vocabulary used by the services. Approach: We propose an appropriate method to assess the adequacy of rendered services. This new method is based on a mathematical representation. It is based on calculating the relevance weight of each service by using the semantic equivalence. Results: Validation of this method was done in two times. Initially, it was implemented and integrated in a retrieval system. In a second step, it was made available to a number of users to give their judgment. Conclusion: The experiments show a high level of satisfaction of this method by improving the quality of the relevance ranking. The relevant services are presented in the first page and the order of relevance decreases with the pages.