FairJudge: Abstention-Aware Multimodal Judges for Fairness and Alignment Evaluation in Text-to-Image Models

Zahraa Al Sahili, Maimuna Nowaz, Maryam Fetanat, Ioannis Patras, Matthew Purver


Abstract
Evaluating text-to-image (T2I) systems requires judging not only whether an image matches a prompt, but also whether socially salient attributes are represented faithfully and without unsupported inference. Existing automated evaluators typically rely on face-centric recognizers or contrastive image–text similarity, which provide limited diagnostic feedback and often force predictions even when visual evidence is ambiguous or absent. For fairness-sensitive attributes such as religion and disability, where cues may be contextual, indirect, or intentionally unspecified, these evaluators can therefore miss failure modes that careful human reviewers would notice.

We introduce FairJudge, an abstention-aware evaluation protocol that uses instruction-following multimodal LLMs as structured judges for social-attribute prediction, profession grounding, and prompt–image alignment. The protocol constrains outputs to closed label sets, requires visible-evidence rationales, supports an explicit unspecified decision when cues are insufficient, and maps rubric-based alignment judgments to . These constraints turn MLLM judging from open-ended assessment into a parseable, auditable evaluation procedure.

Across four attribute-prediction benchmarks and three profession/alignment benchmarks, FairJudge outperforms or complements CLIP, DeepFace, VIEScore, and VQAScore. Ablations show that closed labels, abstention, and evidence reporting are central to reliability. We further introduce DIVERSIFY and DIVERSIFY-Professions, two context-rich resources for evaluating social representation and profession grounding beyond face-visible or iconic cues. We release code, prompts, datasets, parser logs, and per-image judge outputs to support reproducible auditing.
Anthology ID:
2026.findings-aacl.139
Volume:
Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
2700–2718
Language:
URL:
https://aclanthology.org/2026.findings-aacl.139/
DOI:
Bibkey:
Cite (ACL):
Zahraa Al Sahili, Maimuna Nowaz, Maryam Fetanat, Ioannis Patras, and Matthew Purver. 2026. FairJudge: Abstention-Aware Multimodal Judges for Fairness and Alignment Evaluation in Text-to-Image Models. In Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026, pages 2700–2718, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
FairJudge: Abstention-Aware Multimodal Judges for Fairness and Alignment Evaluation in Text-to-Image Models (Al Sahili et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-aacl.139.pdf