Number Needed to Treat (NNT), ,

Because decisions regarding therapy are so common in clinical practice, the application of number needed to treat (NNT) is one of the most important evidence-based medicine skills to be acquired. NNT provides a clinically useful “yardstick” of the effort required to have a beneficial outcome or prevent a bad outcome with a therapy. A brief overview of the concept, derivation, and application of NNT is presented.[Cordell WH: Number needed to treat (NNT). Ann Emerg Med April 1999;33:433-436.]