Another statistical item to watch for
Another thing to watch for is that drugs are often marketed touting their 'relative' benefit, not their 'absolute' benefit.
For example, you may hear that a cholesterol lowering drug reduces your risk of a 2nd heart attack by 40% over a 5 year span, which sounds wonderful. However, the absolute numbers don't sound so great. A group may be followed for 5 years and 97% of those on the drug will have gone without a second heart attack. However, 95% of the control group may have went with out a second heart attack as well. That's only a 2% ABSOLUTE change, but a 40% RELATIVE change.
If your doctor were to tell you that you have only a 2% better chance with the drug, but you will also have to pay $200 a month for the Rx, you may become impotent, you may have insomnia, etc, etc, it doesn't sound too great. But we need to be told the absolute benefit, not the relative one.