He examined the performance of the U.S. stock market since the 1920s, and considered the kinds of expectations of future dividends and discount rates that could justify the wide range of variation experienced in the stock market.
Han undersøgte udviklingen i det amerikanske aktiemarked siden 1920'erne og beregnede, hvilke forestillinger om fremtidige dividender og diskonteringsrater, som kunne retfærdiggøre de store kursudsving i aktierne.