CLEF 15th Birthday: What Can We Learn From Ad Hoc Retrieval?Information Access Evaluation. Multilinguality, Multimodality, and Interaction

This paper reports the outcomes of a longitudinal study on the CLEF Ad Hoc track in order to assess its impact on the effectiveness of monolingual, bilingual and multilingual information access and retrieval systems. Monolingual retrieval shows a positive trend, even if the performance increase is not always steady from year to year; bilingual retrieval has demonstrated higher improvements in recent years, probably due to the better linguistic resources now available; and, multilingual retrieval exhibits constant improvement and performances comparable to bilingual (and, sometimes, even monolingual) ones.