DEEPPERSONA: A Generative Engine for Scaling Deep Synthetic Personas

Synthetic personas support LLM personalization, social simulation, and alignment evaluation, yet existing resources typically represent each individual with only a small number of structured attributes. We introduce DeepPersona, a generative engine that scales persona depth to roughly 200 instantiated taxonomy nodes while preserving narrative coherence. DeepPersona combines (i) a hierarchical taxonomy of 8,496 human-descriptive attributes mined from 62k personalizable QA pairs in real user-chatbot dialogues and (ii) a progressive sampler that conditions each new attribute on the evolving persona and uses a stratified similarity prior to balance coherence and diversity. The same engine can expand shallow inputs, such as PersonaHub entries, into deep profiles. Across three complementary evaluations, DeepPersona improves judge-extracted attribute count by 32% and judge-rated uniqueness by 44% over the strongest prior persona resource; improves LLM personalization quality by up to 11.6% across ten dimensions, with human evaluators preferring DeepPersona responses in 81.2% to 87.0% of pairwise comparisons; and reduces the distributional gap to real World Values Survey responses by 31.7%, while recovering Big Five personality distributions 17% closer to ground truth than the strongest LLM baseline.