http://www.wired.com/2014/10/number-needed-to-treat

Every American needs to be educated on the concept of NNT, or Number Needed to Treat. It is a simple value for any given medication that shows how many people who get that treatment will improve. It's really shocking how often the NNT of commonly used drugs is way too high to justify the cost and risks of treatment. Here is a fun thing you can do at home, ladies: if your doctor suggests that you take statins, ask what the NNT for women is... and if they say anything other than "infinite", get a new doctor!