Calculating NNT:
Using the ARR

•Now we know that the treatment reduced the risk of a proportion of patients, which we call Absolute Risk Reduction and that ARR = CER – EER.

•In other words, ARR is the number of successful treatments beyond baseline expectation divided by the number of treated patients.

•Now we’re close. NNT is the number of treated patients per successful treatments beyond baseline expectation. Can you see the relationship yet?