MADRAG: Multi-Agent Debate with Retrieval-Augmented Generation for Training-Free Analytic Essay Scoring

Ali Keramati, Shiyuan Zhou, Sharad Mehrotra, Mark Warschauer


Abstract
Automated Essay Scoring (AES) is shifting from feature-engineering to LLMs, yet current training-free approaches struggle with calibration, often exhibiting a "middle-score bias" that fails to distinguish between exceptional and weak writings. In this work, we introduce MADRAG (Multi-Agent Debate with Retrieval-Augmented Generation), a training-free framework designed to achieve the reliability of supervised models without the need for labeled training data. MADRAG decomposes the scoring process into a multi-agent interaction: an Advocate highlights essay strengths, a Skeptic critiques weaknesses, and a Judge synthesizes these arguments to assign a score. Crucially, we augment the Judge with RAG mechanism that retrieves rubric-aligned exemplar essays spanning the full score range, grounding the debate in concrete evidence. Evaluating our approach on the ASAP dataset for analytic trait scoring, we demonstrate that MADRAG significantly outperforms existing prompt-based LLM baselines and achieves performance competitive with state-of-the-art supervised models.
Anthology ID:
2026.nlp4dh-1.30
Volume:
Proceedings of the 6th International Conference on Natural Language Processing for the Digital Humanities
Month:
July
Year:
2026
Address:
San Diego, USA
Editors:
Sil Hamilton, Emily Öhman, Rebecca M. M. Hicke, Yuri Bizzoni, Axel Bax, Jacob A. Matthews, Mika Hämäläinen
Venues:
NLP4DH | WS
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Publisher:
Association for Computational Linguistics
Note:
Pages:
325–345
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.nlp4dh-1.30/
DOI:
Bibkey:
Cite (ACL):
Ali Keramati, Shiyuan Zhou, Sharad Mehrotra, and Mark Warschauer. 2026. MADRAG: Multi-Agent Debate with Retrieval-Augmented Generation for Training-Free Analytic Essay Scoring. In Proceedings of the 6th International Conference on Natural Language Processing for the Digital Humanities, pages 325–345, San Diego, USA. Association for Computational Linguistics.
Cite (Informal):
MADRAG: Multi-Agent Debate with Retrieval-Augmented Generation for Training-Free Analytic Essay Scoring (Keramati et al., NLP4DH 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.nlp4dh-1.30.pdf