Cross-language evaluation forum: objectives, results, achievements

The Cross-Language Evaluation Forum (CLEF) is now in its fourth year of activity. We summarize the main lessons learned during this period, outline the state-of-the-art of the research reported in the CLEF experiments and discuss the contribution that this initiative has made to research and development in the multilingual information access domain. We also make proposals for future directions in system evaluation aimed at meeting emerging needs.