One of the most popular SLAs in the software testing discipline is the DRE, why? well, because it measures our own effectiveness as area & process. In my own experience it has been used in large companies to measure the effectiveness of all testing done since unit test, integration test, function test, UAT and production, in that way you can measure what was not found on all these testing phases.
The formula to measure this indicator is:
DRE = (Defects found in my testing phase) / (Defects found in my testing phase + Defects not found in my testing phase)
Enjoy it !
