economics Practical Magic

People will happily take way less interest on their money if you can just prove it isn't fake.

March 18, 2026

Original Paper

Payment Fraud and Welfare 

Qi Li

SSRN · 6340238

The Takeaway

By modeling e-commerce fraud, researchers found that the 'recognizability' of a currency is more valuable than its interest rate. People are so sensitive to the risk of being cheated that they will accept a significantly lower return on their assets just to use a system with slightly better fraud detection.

From the abstract

This paper studies the welfare consequences of imperfect payment recognizability in a monetary search model. Sellers observe a noisy signal of payment authenticity and choose acceptance thresholds that balance fraud losses against the rejection of legitimate payments. The information structure maps directly to the ROC--AUC statistic used to evaluate fraud detection systems, linking modern payment technology to monetary theory. Calibrating the model to e-commerce payment fraud statistics, seller