Generating Constructive Feedback on Stories via Reinforcement Learning

Maja Stahl, Timon Ziegenbein, Henning Wachsmuth


Abstract
Constructive feedback is crucial for creative writers to refine their storytelling abilities. Since receiving feedback from human experts is often costly and time-intensive, large language models (LLMs) offer a scalable and efficient alternative as automatic writing assistants. Despite their potential, research indicates that LLM-generated feedback is often generic, lacks actionability, and fails to identify which writing issue is most critical. To address these limitations, we present a reinforcement learning approach that steers LLMs to generate constructive feedback without the need for ground-truth feedback. We train our model using group relative policy optimization (GRPO) with a novel multi-component reward function aiming at constructiveness: it prioritizes feedback that is uniquely tailored to the story, helps to improve story quality, and addresses the most critical writing issue. In automatic and human evaluation across three story corpora, our approach outperforms state-of-the-art LLMs (including Gemini) and competitive baselines. We find that providing actionable suggestions is the main driver of feedback constructiveness.
Anthology ID:
2026.findings-emnlp.187
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
3976–3994
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.187/
DOI:
Bibkey:
Cite (ACL):
Maja Stahl, Timon Ziegenbein, and Henning Wachsmuth. 2026. Generating Constructive Feedback on Stories via Reinforcement Learning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 3976–3994, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Generating Constructive Feedback on Stories via Reinforcement Learning (Stahl et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.187.pdf