How to Compare Bilingual to Monolingual Cross-Language Information Retrieval

Abstract. The study of cross-lingual Information Retrieval Systems (IRSs) and a deep analysis of system performances should provide guide-lines, hints, and directions to drive the design and development of the next generation MultiLingual Information Access (MLIA) systems. In addition, effective tools for interpreting and comparing the experimen-tal results should be made easily available to the research community. To this end, we propose a twofold methodology for the evaluation of Cross Language Information Retrieval (CLIR) systems: statistical anal-yses to provide MLIA researchers with quantitative and more sophisti-cated analysis techniques; and graphical tools to allow for a more quali-tative comparison and an easier presentation of the results. We provide concrete examples about how the proposed methodology can be applied by studying the monolingual and bilingual tasks of the Cross-Language Evaluation Forum (CLEF) 2005 and 2006 campaigns.