 Number needed to treat

The Number Needed to Treat (NNT) is a statistical measure used in healthcare to estimate the effectiveness of a treatment. It indicates the number of patients that need to be treated with a particular intervention in order for one patient to benefit from that treatment compared to a control group (usually receiving a placebo or standard care). The NNT is calculated from the absolute risk reduction (ARR), which is the difference in the event rate (e.g.