Keep non-inferiority margin fixed
EVENTS, EVENT
This is the most powerful strategy in situations where the control event risk was correctly predicted at the design stage of the trial (Fig. Results of three examples with various analysis methods, including the “keep NI margin fixed method” and four possible implementations of the SAFE frontier. The examples are (1) 22 events in both arms, (2) 15 events in the control and 22 in the experimental arm and (3) 2 events in the control and 10 in the experimental arm. The total sample size is fixed to 185 per arm in all examples, equal to the planned D3 sample size