Test Effectiveness, Test Efficiency, Defect Removal Efficiency (DRE) - Jargons :)

I was talking to a colleague today around difference among these test metrics and I am sharing it with you all if it helps :)

 

Test Case Effectiveness = Total defects found by test cases / Total defects**

e.g. if 80 defects were found by test cases and 10 were through ad hoc testing and 10 were leaked to UAT / Prod then TC effectiveness is 80 %

 

** This includes all defects found post build  phase (after test cases are designed) so if buddy testing was done then sure it should be added to total defects as we will use our test cases to do buddy testing.  Total defects will also include the defects found in UAT and post production as they are leakages.

 

Test Efficiency = No. of valid defects  / Total Defects found by test team (including invalid defects)

 

e.g. if 90 defects out of 100 were accepted then Test efficiency is 90 %

 

This gives us the rework and wastage due to invalid bugs that we rejected

 

Defect Removal Efficiency (DRE)  = Total defect found before delivery (through review, inspection, testing etc) / Total defect during project lifetime

 

Here we are saying doesn’t matter if we found them by test case or reviews, if we found them before UAT then its good and the defects that are found in UAT and Prod will be added to denominator and will show our DRE.