Revealing economic facts: LLMs know more than they say
Marcus Buckmann, Quynh Anh Nguyen, Edward Hill
TL;DR
This study shows that hidden states (embeddings) of open-source LLMs contain richer economic information than the models' textual outputs. A simple ridge regression on embeddings (LME) frequently outperforms the LLM's own answers for estimating county- and firm-level statistics, especially for rarer variables, and requires only a small number of labelled examples. The authors also introduce transfer-learning approaches that estimate target variables without labels by leveraging embeddings from other variables or noisy text labels, achieving robust improvements. Additionally, embeddings prove useful for data-processing tasks such as imputation and super-resolution, enhancing practical data pipelines without requiring knowledge of the target statistics during training.
Abstract
We investigate whether the hidden states of large language models (LLMs) can be used to estimate and impute economic and financial statistics. Focusing on county-level (e.g. unemployment) and firm-level (e.g. total assets) variables, we show that a simple linear model trained on the hidden states of open-source LLMs outperforms the models' text outputs. This suggests that hidden states capture richer economic information than the responses of the LLMs reveal directly. A learning curve analysis indicates that only a few dozen labelled examples are sufficient for training. We also propose a transfer learning method that improves estimation accuracy without requiring any labelled data for the target variable. Finally, we demonstrate the practical utility of hidden-state representations in super-resolution and data imputation tasks.
