Auditing Bias Detection Under Source Shift: A Source-Aware Benchmark and Evaluation Protocol

Ana Pinto, Alvaro Figueira


Abstract
Bias-detection benchmarks routinely report accuracies above 90%, but a high number can reflect where a sentence came from as much as whether it contains a stereotype or an unfair claim about a group. We treat this as an evaluation problem and propose an integrated auditing protocol that makes source confounding measurable: an LLM-assisted label audit with cross-family verification, pair-aware splitting with role tracking, source-aware evaluation with a source-only baseline on the actual test split, counterfactual discrimination, and an artifact analysis of edited text. We apply it to a three-source corpus of 10,304 sentences that we audit and release. The audit reduces the global source-only majority baseline from 95.0% to 55.4%, and the same protocol shows that the real-only test split still carries a 77.6% source-only baseline, so confounding is reduced and measured but far from eliminated. Against that baseline, fine-tuned BERT and GPT-2 gain roughly 18 pp and outperform attention-derived models; four augmentation variants that look ordered in the mean fall within seed variance under paired testing; and a real-vs-edited probe separates Gemini counterfactuals from real text, although the signal disappears once the gold label is held fixed and has no measurable accuracy effect. Applied to CrowS-Pairs, the label audit flags 33.2% of the supposedly neutral members as still containing a group-level stereotype. The main contribution is the protocol, which exposes confounding that standard pipelines would report as results.
Anthology ID:
2026.aacl-short.55
Volume:
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 2: Short Papers)
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venues:
AACL | IJCNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
854–878
Language:
URL:
https://aclanthology.org/2026.aacl-short.55/
DOI:
Bibkey:
Cite (ACL):
Ana Pinto and Alvaro Figueira. 2026. Auditing Bias Detection Under Source Shift: A Source-Aware Benchmark and Evaluation Protocol. In Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 2: Short Papers), pages 854–878, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
Auditing Bias Detection Under Source Shift: A Source-Aware Benchmark and Evaluation Protocol (Pinto & Figueira, AACL-IJCNLP 2026)
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PDF:
https://aclanthology.org/2026.aacl-short.55.pdf