CLEF 2021 is the 12th CLEF conference continuing the popular CLEF campaigns which have run since 2000 contributing to the systematic evaluation of information access systems, primarily through experimentation on shared tasks.

Building on the format first introduced in 2010, CLEF 2021 consists of an independent peer-reviewed conference on a broad range of issues in the fields of multilingual and multimodal information access evaluation, and a set of labs and workshops designed to test different aspects of mono and cross-language Information retrieval systems. Together, the conference and the lab series will maintain and expand upon the CLEF tradition of community-based evaluation and discussion on evaluation issues.

CLEF 2021 will be an online event broadcast from the University "Politehnica" of Bucharest, Romania, 21-24 September 2021.

***The COVID-19 pandemic has imposed unprecedented changes in our personal and professional lives. Although the pandemic force weakened worldwide and the vaccination campaigns are more and more effective, as much as we were keen to welcome you in Bucharest, we made the difficult decision of having CLEF 2021 also as a virtual event. Our safety and health are the most important. The conference will build on the success of the past similar events thus ensuring a smooth transition and interaction.***

***Thanks to our supporters and sponsors, participation to the conference is free of charge. Prospective participants are expected to formally register their participation to be able to receive all the connection instructions. Click here to register your participation to the conference.***