Steep frontier
non-immediate
EVENT
A similar, but less extreme, frontier allows for a non-immediate change in non-inferiority margin, but a continuous, though very steep, linear decrease in the non-inferiority margin from 10 to 8 percentage points between control event risks of 9 to 8% first, and from 8 to 5 percentage points between control event risks of 5 to 4%. The advantage of this frontier is that it avoids dichotomisation of the non-inferiority margin choice, though such a steep frontier might be considered unrealistic in terms of clinical significance.