The price-to-earnings ratio might be the most polarizing statistic in investing. Some investors call it a basic core tenet for judging stocks; others see it as a misguided and useless tool. Strong earnings or a big run-up in share price can skew the P/E ratio toward more expensive stocks, but how does this classic statistic measure up when viewing Big Pharma's priciest picks?

Using data compiled from stock screening site Finviz, let's check out the three most expensive stocks among major pharmaceutical developers. In the following video, Fool contributor Dan Carroll tells you what you need to know about these stocks -- and whether their outlooks are worth the pretty penny you'll pony up to buy them.