Stepped frontier
EVENT
This frontier is defined by a step function that assigns a non-inferiority margin of 8 percentage points when the control event risk is between 5 and 9% and 5 percentage points for control event risks at or below 5%. Its advantage is the straightforward definition and interpretation, while the disadvantage is the dichotomisation of the choice of non-inferiority margin for event risks larger or smaller than 5% or 9%.