smart companies aggressively shift their offerings from high physical content to high knowledge content.

In theory, the value of a stock is a prediction of a company’s future earnings and dividends. Although earnings may be hard to predict, you can look at what a company has made in the recent past (Shiller’s formula uses the past ten years of earnings) and compare it with the value of the stock. This calculation—known as the P/E or price-to-earnings