arXiv AI

Probable but Not Valid: A Psychometric Audit of Decision Models as Synthetic Survey Respondents

arXiv Computation and Language
Sep 23

Do Synthetic Personas Predict Real Audience Response? A Sim-to-Real Study Where a No-Persona Baseline Beats Persona-Based Copy Simulation

The study evaluates whether large language models (LLMs) used as synthetic personas can predict real audience responses to marketing copy. Using thousands of headline A/B tests from the Upworthy Research Archive, the authors compare a ten-persona panel grounded in real audience demographics to a no-persona zero‑shot baseline that asks the model for a typical reader’s click likelihood. Results show that the no‑persona baseline outperforms the persona‑based approach, with higher predictive validity and top‑1 accuracy, indicating that forcing the model to role‑play specific personas introduces bias and noise.

By Alexandre Cristov\~ao Maiorano
arXiv Computation and Language
2d ago

Item-Mean Surrogates: Why Richer Personas Fail to Deliver Individual Fidelity in LLMs as Human Surrogates

The study investigates whether large language models (LLMs) can accurately simulate individual human responses by testing the assumption that richer personas improve prediction fidelity. Across four public datasets, researchers found that LLMs largely predict item means but fail to capture individual deviations, particularly the stable, person‑by‑item signal that accounts for most variance. Even with fine‑tuning and varied models, LLMs recover only a small fraction of this nuanced signal, highlighting limitations in using them as precise human surrogates.

By Daehwan Ahn, Chengfeng Mao, Dokyun Lee
arXiv AI
Sep 2

Consistency Without Alignment: Item-Sensitive Language Models Indistinguishable From Random

The paper investigates item-sensitivity—whether a language model’s choice depends on the specific input—in a forced-choice signalling task derived from the board game Deception: Murder in Hong Kong. Across seven models, two families, a post‑training ablation, and three scoring rules, every tested cell shows item‑sensitivity, yet many are statistically indistinguishable from random choice and some perform worse than random. The authors term this phenomenon "consistency without alignment" and argue it undermines evaluations that rely solely on item‑sensitivity, permutation consistency, or self‑consistency without an independent reference.

By Cris Huynh
arXiv Computation and Language
2d ago

Diagnosing Model--Item Interactions in Language Model Benchmarks with LSIRM

The paper introduces the latent space item response model (LSIRM) as a tool for uncovering how language models differ on specific benchmark items. By mapping 1,348 models across 5,761 BBH items and comparing scoring methods across BBH, GPQA, MMLU-Pro, and MuSR, the authors show that items with similar correct answers cluster together, especially when scored by option labels. LSIRM separates a model’s tendency to perform better on certain answer categories from other performance differences, revealing that small changes in scoring can dramatically alter model rankings.

By Jinwen Luo, Han Jiang, Ziang Xiao, Susu Zhang