(apologies for cross-posting)

Dear colleague,

We invite you to participate in the 2025 edition of the CheckThat! Lab at CLEF 2025. This year, we feature four tasks ---one follow-up and three new--- that correspond to important components within and around the full fact-checking pipeline in multiple languages:

Task 1 Subjectivity in news articles. to spot text that should be processed with specific strategies; benefiting the fact-checking pipeline. Available in Arabic, English, Bulgarian, German, Italian, and Multilingual.

Task 2 Claim Normalization. to simplify the primary claim made in the social media post into a concise form. This task is offered in 20 languages: English, Arabic, Bengali, Czech, German, Greek, French, Hindi, Korean, Marathi, Indonesian, Dutch, Punjabi, Polish, Portuguese, Romanian, Spanish, Tamil, Telugu, Thai.

Task 3 Fact-Checking Numerical Claims. to verify claims with numerical quantities and temporal expressions. Available in Arabic, English and Spanish.

Task 4 Scientific Web Discourse Processing (SciWeb). to (a) classify different forms of science-related online discourse and (b) retrieve the scientific paper that serves as the source for the claim from a given pool of candidate scientific papers. Available in English.

Register and participate: https://clef2025-labs-registration.dei.unipd.it/registrationForm.php

Further information: https://checkthat.gitlab.io/

Datasets: https://gitlab.com/checkthat_lab/clef2025-checkthat-lab

Important Dates

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- November 2024: Lab registration opens

- December 2024: Release of the training materials

- 25 April 2025: Lab registration closes

- 30 April 2025: Beginning of the evaluation cycle (test sets release)

- 10 May 2025 (23:59 AOE): End of the evaluation cycle (run submission)

- 30 May 2025: Deadline for the submission of working notes [CEUR-WS]

- 30 May – 27 June 2025: Review process of participant papers

- 9 June 2025: Submission of Condensed Lab Overviews [LNCS]

- 16 June 2025: Notification of Acceptance for Condensed Lab Overviews [LNCS]

- 23 June 2025: Camera Ready Copy of Condensed Lab Overviews [LNCS] due

- 27 June 2025: Notification of Acceptance for Participant Papers [CEUR-WS]

- 7 July 2025: Camera Ready Copy of Participant Papers and Extended Lab Overviews [CEUR-WS] due

- 21-25 July 2025: CEUR-WS Working Notes Preview for Checking by Authors and Lab Organizers

- 9-12 September 2025: CLEF 2025 Conference in Madrid, Spain

Best regards,

The CLEF-2025 CheckThat! Lab Shared Task Organizers