I call this indicator the "Alpha Score."

I'll tell you more about this indicator in a second, but just know that a stock's Alpha Score can range from 0 to 200. The higher the number, the more potential the stock has.

For example, you've probably never heard of Westmoreland Coal (Nasdaq: WLB). It operates six surface coal mines and two power generating units in the western United States. The company looked promising when we recommended it on Dec. 18, 2013. Westmoreland had sold 95% of its future production under long-term contracts, and the market for coal looked stable.

But that's not what attracted us to the stock. What most investors didn't know about Westmoreland is that it had an Alpha Score of 158. Less than 1% of stocks have a score that high at any given time.