Table 2 

Approximate sample sizes required for noninferiority comparison of proportions 

True proportion in active control 
Noninferiority bound using 10% margin 
Approximate sample size per group assuming 1:1 randomization to new treatment and control required under: 



Equal effects 
5% benefit 
10% benefit 



0.1 
0.09 
19,200 
8,725 
5,050 


0.2 
0.18 
8,500 
3,900 
2,250 


0.3 
0.27 
4,970 
2,260 
1,300 


0.4 
0.36 
3,200 
1,450 
825 


0.5 
0.45 
2,100 
1,000 
550 


0.6 
0.54 
1,440 
640 
360 


0.7 
0.63 
930 
405 
225 


Sample sizes calculated using Pass 2008 methods for noninferiority tests of two independent proportions, using the Z statistic with continuity correction and pooled variance, with a target power of 90% and α level of 0.025. 

Schumi and Wittes Trials 2011 12:106 doi:10.1186/1745621512106 