Exponential Growth Bias in an Inflationary World

Abstract

This paper examines the exponential growth bias (EGB), both compound savings questions and in a domain relevant to household finance: inflation-based questions. Here, we test a broad-based sample of 354 adults living in the US initially on estimates for future compound savings and future prices after inflation over time. Here, we find significant EGB in both domains with and without calculators, with significantly higher bias sizes in the inflation questions. After the initial results, each participant completed a short 5 to 10-minute tutorial designed to teach them about EGB. We split the overall participants into two random learning groups: One group was shown how to use interactive charts while the other group learned the formal formula. While we do not find any significant differences of improvements between the two learning groups, we find significantly large decreases in bias sizes in both savings and inflation questions after the tutorial, with and without a calculator, particularly for those who did not know how to make the correct calculation before the tutorial.