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Main Authors: Gao, Wayne, Han, Sukjin, Liang, Annie
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2601.12343
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author Gao, Wayne
Han, Sukjin
Liang, Annie
author_facet Gao, Wayne
Han, Sukjin
Liang, Annie
contents Large language models (LLMs) are increasingly used to predict human behavior. We propose a measure for evaluating how much knowledge a pretrained LLM brings to such a prediction: its equivalent sample size, defined as the amount of task-specific data needed to match the predictive accuracy of the LLM. We estimate this measure by comparing the prediction error of a fixed LLM in a given domain to that of flexible machine learning models trained on increasing samples of domain-specific data. We further provide a statistical inference procedure by developing a new asymptotic theory for cross-validated prediction error. Finally, we apply this method to the Panel Study of Income Dynamics. We find that LLMs encode considerable predictive information for some economic variables but much less for others, suggesting that their value as substitutes for domain-specific data differs markedly across settings.
format Preprint
id arxiv_https___arxiv_org_abs_2601_12343
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle How Well Do LLMs Predict Human Behavior? A Measure of their Pretrained Knowledge
Gao, Wayne
Han, Sukjin
Liang, Annie
Econometrics
Artificial Intelligence
Machine Learning
Large language models (LLMs) are increasingly used to predict human behavior. We propose a measure for evaluating how much knowledge a pretrained LLM brings to such a prediction: its equivalent sample size, defined as the amount of task-specific data needed to match the predictive accuracy of the LLM. We estimate this measure by comparing the prediction error of a fixed LLM in a given domain to that of flexible machine learning models trained on increasing samples of domain-specific data. We further provide a statistical inference procedure by developing a new asymptotic theory for cross-validated prediction error. Finally, we apply this method to the Panel Study of Income Dynamics. We find that LLMs encode considerable predictive information for some economic variables but much less for others, suggesting that their value as substitutes for domain-specific data differs markedly across settings.
title How Well Do LLMs Predict Human Behavior? A Measure of their Pretrained Knowledge
topic Econometrics
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2601.12343