Submitted on:14.08.2017 1 Satellite Meeting - Reference and Information Services & Information Technology Sections: Innovation and the User Experience: Evaluating and Implementing Discovery Systems Resource Discovery Services versus OPACs in Information Searching Blanca Rodríguez-Bravo Library and Information Science, University of León, León, Spain. blanca.rodriguez@unileon.es José-Antonio Frías Library and Information Science, University of Salamanca, Spain. frias@usal.es Copyright © 2017byBlanca Rodríguez-Bravo and José-Antonio Frías.This work is made available under the terms of the Creative Commons Attribution 4.0 International License:http://creativecommons.org/licenses/by/4.0 Abstract: In order to learn more about the strengths and weaknesses of Resource Discovery Services (RDS) and Online Public Access Catalogues (OPAC), we selected three universities from Spain which met the following requirements: 1) they taught Library and Information Science Studies, since our expertise in this scientific field would enable us to determine the relevance of the results retrieved, and 2) they had implemented different tools. We conducted several subject and author searches in RDS and OPAC, with the overall objective of exploring the efficiency of the search process and the relevance of the results retrieved when using each tool. The specific objectives were: to determine the comprehensiveness of the relevant results retrieved in a parallel search of OPAC and Resource Discovery Services; to analyze these results; to identify the filter functions for selection in RDS and OPAC; to determine the ease with which the results could be refined and/or the search could be widened by making use of facets, indexes, or advanced search features; and to assess the implementation and usefulness of recommendations of related documents and user opinions/reviews in the form of tags, comments and ratings. Keywords: Evaluation; Information searching, OPACs, Resource Discovery Services, Spanish Universities