In the example we have used, the NNT was calculated as a whole value, but this is rarely the case. Suppose that in our previous example the experimental event rate had been 60%. The NNT would then be 3.3. In all cases the NNT is rounded up, so in this case it would be 4.

In a perfect world an intervention would have an NNT of 1, meaning that everyone would experience the benefit of the drug. Unfortunately, an NNT of 1 is very rare, but the smaller the NNT, the better the intervention.

So what do you think is an acceptable maximum NNT? Move the slider below to register your view, then click 'Feedback'.

NNT 10

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