In our Dec. 6 edition of MarketFoolery, Rich Greifner sheds some light on a common metric that investors use when evaluating retailers: same-store-sales. Rich likes the metric but thinks it can be misleading. 

Instead, he suggests looking at the breakdown of newer locations compared with older ones. That's important, because some high-growth retailers such as Chipotle (NYSE: CMG) or Ulta Salon (Nasdaq: ULTA) may look expensive when evaluating their same-store-sales in aggregate, but when you break it out differently, you can more easily see how they'll continue to put up big growth numbers.