| Group | Event | ||
| Occurred (Y = 1) | Not occurred (Y = 0) | Total | |
| Treatment (X = 1) | n11,1 + n10,1 | n00,1 + n01,1 | n11,1 + n10,1 + n01,1 + n00,1 |
| Control (X = 0) | n11,0 + n01,0 | n00,0 + n10,0 | n11,0 + n10,0 + n01,0 + n00,0 |
| Total | n11 + n10,1 + n01,0 | n00 + n01,1 + n10,0 | n |