Detecting Lookahead Bias in LLM Forecasts
Researchers have developed a new statistical method to identify lookahead bias in economic forecasts generated by large language models (LLMs). This method, termed Lookahead Propensity (LAP), quantifies the likelihood that an LLM has incorporated future information into its predictions. The procedure was tested on LLM forecasts for stock returns and capital expenditures, revealing that forecasts with higher LAP scores were more predictive, but this effect diminished when data after the LLM's training cutoff was excluded. The LAP test is presented as a cost-efficient tool for validating LLM-generated forecasts. AI
IMPACT Introduces a method to improve the reliability of LLM-generated economic forecasts, crucial for financial applications.