Thirty years ago, Ken Fisher burst on the investment scene with his book Super Stocks, in which he showed that investors often focused too much on earnings while ignoring sales and other metrics. Three decades later, Fisher says investors haven’t learned their lesson.

Thirty years ago, Ken Fisher burst on the investment scene with his book Super Stocks, in which he showed that investors often focused too much on earnings while ignoring sales and other metrics. Three decades later, Fisher says investors haven’t learned their lesson.