Published October 9, 2026
The Cyclically Adjusted Price-to-Earnings (CAPE) ratio, also known as the Shiller PE, is one of the most widely regarded measures for evaluating long-term stock market valuations. Developed by Yale Professor Robert Shiller, it was first presented in his 1988 research paper, “Stock Prices, Earnings, and Expected Dividends.” Shiller famously leveraged the ratio in his book Irrational Exuberance to accurately predict the popping of the dot-com bubble. (more…)