How does the Fama-French three-factor model explain stock returns differently than a model that only looks at the stock's sensitivity to the broad market?

The standard market model says that a stock's return is mostly determined by how it moves with the overall stock market. If the whole market goes up, your stock goes up; if the market goes down, your stock goes down. This is like saying a boat's speed is only set by the speed of the river it is floating on. The Fama-French three-factor model adds two more pieces to the puzzle to bette....