Contextual Diversity Measure (CDM) for Controllable Story Generation in Large Language Models

Richard Susilo, Hanna Suominen, Patrik Haslum


Abstract
Scenario-based text generation has broad applications across education and creative writing, but remains underexplored in controllable text generation. We introduce the Contextual Diversity Measure (CDM), a metric that quantifies semantic diversity for scenario generation under fixed abstract semantic constraints, and validate it through controlled experiments. Statistical analysis across four embedding models demonstrates that CDM successfully distinguishes between high-diversity and low-diversity text pairs, with all tests achieving statistical significance at p < 0.05 on both the manually curated and LLM-generated subsets of the dataset. Effect sizes range from small-to-medium (Cohen’s d: 0.292–0.508) on the former and medium-to-large (Cohen’s d: 0.677–1.195) on the latter. Baseline comparisons indicate that CDM achieves excellent discrimination accuracy (100% and 91.9%, respectively), with discriminative power up to 5.5× greater than the best baseline.
Anthology ID:
2026.acl-srw.98
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Santosh T.Y.S.S., Juan Diego Rodriguez, Ona de Gibert
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1125–1138
Language:
URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-srw.98/
DOI:
Bibkey:
Cite (ACL):
Richard Susilo, Hanna Suominen, and Patrik Haslum. 2026. Contextual Diversity Measure (CDM) for Controllable Story Generation in Large Language Models. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026), pages 1125–1138, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Contextual Diversity Measure (CDM) for Controllable Story Generation in Large Language Models (Susilo et al., ACL 2026)
Copy Citation:
PDF:
https://preview.aclanthology.org/ingest-acl/2026.acl-srw.98.pdf