Table 1.

The probability of finding a single case of an adverse event with a certain incidence in a certain group size^*

	Incidence (%)
n	0.1	1	10
10	0.010	0.096	0.651
20	0.020	0.182	0.878
30	0.030	0.260	0.958
40	0.039	0.331	0.985

^*For example, a serious event with a population incidence of 1% will have an 18.2% chance of being detected once in a group of 20 subjects.