Back in Style: A Sociolinguistic Approach to Authoring and Measuring Persona Fidelity in User Simulation
This study addresses the low fidelity of user simulators and their reliance on costly, subjective LLM-based evaluation by proposing an objective assessment framework grounded in sociolinguistics. Methodologically, personality is reconceptualized as observable linguistic style rather than a label prediction task, enabling deterministic measurement through specific style rates. By integrating stylometric and lexicon-based analysis techniques, the framework introduces model-free validation tools for objective diagnostics. Experimental results demonstrate that this approach significantly enhances both style adherence and discriminability across most models, offering a novel pathway for precisely identifying simulation errors and generating diverse user profiles.