Simple Interactive Statistical Analysis
On the Number Needed to Treat.
In this paper the use of the NNT is compared with other measures of association. The NNT has the advantage of being easy to interpret particularly in relation to cost benefit analysis. However, the measure has a number of very undesirable properties such as that the range is interrupted, there are no valid values between -1 and 1, and that the confidence interval has to be able to incorporate infinity. These problems are particularly important if one wants to use the NNT for statistical significance testing.
This paper has moved to this location.