The NNT (NNT stands for Number Needed To Treat) is an outstanding website for medical decision making that both doctors and patients will find useful. The link is to the home page and the page brilliantly explains how to use the site for medical decision making. [Dr. Weingart of the EM Crit website recommended this site in one of his podcasts]
There are additional sites mentioned by The NNT for medical decision making that I have included in the Resources section at the end.
Resources
MD Calc: The Medical Calculator
JAMA Evidence–The Rational Clinical Examination Series
