Shares of Bristol-Myers Squibb (BMY 0.55%) have soared more than 27% since the start of this year, surpassing not only the S&P 500, but also its peers Eli Lilly (LLY -1.94%) and AstraZeneca (AZN 1.03%). What have been the main drivers of this growth, and how is Bristol-Myers valued today compared to other stocks in this competitive industry? In the following segment, taken from The Motley Fool's health care show Market Checkup, health care analysts David Williamson and Max Macaluso discuss an important valuation metric that all investors should pay attention to and why Bristol-Myers trades at a premium to many of its peers.