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Number needed to understand

By Timothy Cocks Science and the world 09 Jun 2016

The Number Needed to Treat (NNT) is a commonly used measure to communicate the effectiveness of a health care intervention. It really is a beautiful thing – just a single number, no distracting percentage, no associated Greek symbol and a simple “the lower the better” rule.


What does it really mean?

Tran Quang Hung has written a wonderful, plain language post at

“We conducted a randomized trial to test the efficacy of SuperMed. There were 2 groups: a group treated with SuperMed and a group treated with placebo. 100 patients in each.

In the group treated with SuperMed, 75% patients were still alive after a 1-year course. In the group treated with placebo, only 25% patients survived.

So, you can see 25% patients don’t die regardless of the lack of a “real” drug. 25% will die, even if they get an effective drug. SuperMed helps 50% of patients survive. It means that for every two patients, SuperMed prevents one death. The NNT is 2”

“The number needed to treat (NNT) is defined as the expected number of people who need to receive the experimental rather than the comparator intervention for one additional person to either incur or avoid an event in a given time frame.”

There are a number of important nuances with NNTs – go and read the whole post, it’s well worth it.

-Tim Cocks



We’re hitting the road and taking our NOI courses right across this great southern land:

Noosa 17 – 19 June Explain Pain and Graded Motor Imagery (Both courses SOLD OUT)

Wagga Wagga 16-17 July Explain Pain

Perth 15 – 17 October Explain Pain and Graded Motor Imagery


EP3 events have sold out three years running in Australia, and we are super excited to be bringing this unique format to the United States in late 2016 with Lorimer Moseley, Mark Jensen, David Butler, and few NOI surprises.

EP3 EAST Philadelphia, December 2, 3, 4 2016

EP3 WEST Seattle, December 9, 10, 11 2016

To register your interest, contact NOI USA:

p (610) 664-4465



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