Item-Mean Surrogates: Why Richer Persona Data Fail to Improve LLMs as Human Surrogates
LLMs are increasingly used as human surrogates, often on the premise that richer persona data could make them substitutes or exploratory tools for specific individuals. We test this premise across four datasets covering more than 400,000 participants and more than 6,000 survey items and experimental outcomes. LLMs perf...