PersonaTwin: A Multi-Tier Prompt Conditioning Framework for Generating and Evaluating Personalized Digital Twins

Sihan Chen, John P. Lalor, Yi Yang, Ahmed Abbasi


Abstract
While large language models (LLMs) afford new possibilities for user modeling and approximation of human behaviors, they often fail to capture the multidimensional nuances of individual users. In this work, we introduce PersonaTwin, a multi-tier prompt conditioning framework that builds adaptive digital twins by integrating demographic, behavioral, and psychometric data. Using a comprehensive data set in the healthcare context of more than 8,500 individuals, we systematically benchmark PersonaTwin against standard LLM outputs, and our rigorous evaluation unites state-of-the-art text similarity metrics with dedicated demographic parity assessments, ensuring that generated responses remain accurate and unbiased. Experimental results show that our framework produces simulation fidelity on par with oracle settings. Moreover, downstream models trained on persona-twins approximate models trained on individuals in terms of prediction and fairness metrics across both GPT-4o-based and Llama-based models. Together, these findings underscore the potential for LLM digital twin-based approaches in producing realistic and emotionally nuanced user simulations, offering a powerful tool for personalized digital user modeling and behavior analysis.
Anthology ID:
2025.gem-1.66
Volume:
Proceedings of the Fourth Workshop on Generation, Evaluation and Metrics (GEM²)
Month:
July
Year:
2025
Address:
Vienna, Austria and virtual meeting
Editors:
Kaustubh Dhole, Miruna Clinciu
Venues:
GEM | WS
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Publisher:
Association for Computational Linguistics
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Pages:
774–788
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URL:
https://preview.aclanthology.org/corrections-2025-08/2025.gem-1.66/
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Cite (ACL):
Sihan Chen, John P. Lalor, Yi Yang, and Ahmed Abbasi. 2025. PersonaTwin: A Multi-Tier Prompt Conditioning Framework for Generating and Evaluating Personalized Digital Twins. In Proceedings of the Fourth Workshop on Generation, Evaluation and Metrics (GEM²), pages 774–788, Vienna, Austria and virtual meeting. Association for Computational Linguistics.
Cite (Informal):
PersonaTwin: A Multi-Tier Prompt Conditioning Framework for Generating and Evaluating Personalized Digital Twins (Chen et al., GEM 2025)
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https://preview.aclanthology.org/corrections-2025-08/2025.gem-1.66.pdf