Stock Returns: Between Shiller and DeLong

Robert Shiller had a piece in the Sunday NYT noting that the S&P 500 was unusually high relative to his measure of trailing earnings. He calculated a ratio above 25, far above the historic average of 15. Shiller said that in the past, each time this ratio crossed 25 the market took a plunge shortly thereafter. He concludes his piece by seeing it as a mystery that the market remains as high as it does.

Brad DeLong picks up on Shiller's analysis and points out that in most cases in the past...