Speed Reads

Evidence-based medicine

This stat explains how effective your medicine really is

This stat explains how effective your medicine really is

It's called the "number needed to treat," or NNT. As Aaron Carroll explains below, it's how many people need to take a particular treatment for one of them to receive the advertised benefit. For example, if we imagine a treatment for the common cold with an NNT of 5, that means for every person whose cold was successfully treated, 4 people took the medicine for no benefit.

Sounds simple, right? What's amazing is just how high this number can be. Even very famous and well-accepted treatments often have NNTs in the hundreds or thousands. Watch the video for the full explanation. --Ryan Cooper