@inproceedings{NakovDaSanMartinoElsayedetal., author = {Nakov, Preslav and Da San Martino, Giovanni and Elsayed, Tamer and Barr{\´o}n-Cede{\~n}o, Alberto and M{\´i}guez, Rub{\´e}n and Shaar, Shaden and Alam, Firoj and Haouari, Fatima and Hasanain, Maram and Mansour, Watheq and Hamdan, Bayan and Sheikh Ali, Zien and Babulkov, Nikolay and Nikolov, Alex and Koshore Shahi, Gautam and Struß, Julia Maria and Mandl, Thomas and Kutlu, Mucahid and Selim Kartal, Yavuz}, title = {Overview of the CLEF-2021 CheckThat! Lab on Detecting Check-Worthy Claims, Previously Fact-Checked Claims, and Fake News}, series = {Experimental IR Meets Multilinguality, Multimodality, and Interaction}, booktitle = {Experimental IR Meets Multilinguality, Multimodality, and Interaction}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-85251-1}, doi = {10.1007/978-3-030-85251-1_19}, pages = {264 -- 291}, abstract = {We describe the fourth edition of the CheckThat! Lab, part of the 2021 Conference and Labs of the Evaluation Forum (CLEF). The lab evaluates technology supporting tasks related to factuality, and covers Arabic, Bulgarian, English, Spanish, and Turkish. Task 1 asks to predict which posts in a Twitter stream are worth fact-checking, focusing on COVID-19 and politics (in all five languages). Task 2 asks to determine whether a claim in a tweet can be verified using a set of previously fact-checked claims (in Arabic and English). Task 3 asks to predict the veracity of a news article and its topical domain (in English). The evaluation is based on mean average precision or precision at rank k for the ranking tasks, and macro-F1 for the classification tasks. This was the most popular CLEF-2021 lab in terms of team registrations: 132 teams. Nearly one-third of them participated: 15, 5, and 25 teams submitted official runs for tasks 1, 2, and 3, respectively.}, subject = {Desinformation}, language = {en} } @inproceedings{NakovDaSanMartinoElsayedetal., author = {Nakov, Preslav and Da San Martino, Giovanni and Elsayed, Tamer and Barr{\´o}n-Cede{\~n}o, Alberto and M{\´i}guez, R{\´u}ben and Shaar, Shaden and Alam, Firoj and Haouari, Fatima and Hasanain, Maram and Babulkov, Nikolay and Nikolov, Alex and Shahi, Gautam Kishore and Struß, Julia Maria and Mandl, Thomas}, title = {The CLEF-2021 CheckThat! Lab on Detecting Check-Worthy Claims, Previously Fact-Checked Claims, and Fake News}, series = {Advances in Information Retrieval}, booktitle = {Advances in Information Retrieval}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-72240-1}, doi = {10.1007/978-3-030-72240-1_75}, pages = {639 -- 649}, abstract = {We describe the fourth edition of the CheckThat! Lab, part of the 2021 Cross-Language Evaluation Forum (CLEF). The lab evaluates technology supporting various tasks related to factuality, and it is offered in Arabic, Bulgarian, English, and Spanish. Task 1 asks to predict which tweets in a Twitter stream are worth fact-checking (focusing on COVID-19). Task 2 asks to determine whether a claim in a tweet can be verified using a set of previously fact-checked claims. Task 3 asks to predict the veracity of a target news article and its topical domain. The evaluation is carried out using mean average precision or precision at rank k for the ranking tasks, and F1 for the classification tasks.}, subject = {Falschmeldung}, language = {en} }