HOW DOES THE LINCOLN INDEX WORK?
Suppose the two testers have probabilities P1 and P2 of finding any given bug and
assume the application contains B bugs. Then you would expect them to find
E1 = P1 × B and E2 = P2 × B bugs, respectively.
The chance of a particular bug being found by both testers would be P1 × P2 , so you
would expect them to fi nd S = P1 × P2 × B bugs in common.
Plugging those values into the formula for the Lincoln index gives