I have some idea about defect leakage. Can anyone let me know what is the correct definition or term of the defect leakage formula?

  • Defect Leakage (%) = 100% - DRE (%) Nov 12, 2017 at 12:33
  • Related: sqa.stackexchange.com/questions/29395/… but not marking as a duplicate since that one didn't really have a complete answer in terms of the actual formula.
    – c32hedge
    Nov 12, 2017 at 21:50
  • DRE appears to stand for "Defect Removal Efficiency" if anyone else was staring at it wondering.
    – c32hedge
    Nov 12, 2017 at 21:54

2 Answers 2


Defect leakage formula is defined as -

Number of Defects slipped / (Number of Defects raised - Number of Defects withdrawn)

Example: In production the customer raises 21 issues, during your tests 267 Issues were reported but there were 17 invalid defects (e.g. because of wrong tests, mistake by tester, error in test environment...)

Then your Defect Leakage Ratio would be:

[21/(267-17)] x 100 = 8.4%

  • Should defects found in production not be lowered by the number of defects that could not be found in a not production environment?
    – Patrick
    Nov 15, 2017 at 7:57
  • that's why it's 21 and not 267. Nov 15, 2017 at 17:16

Defect leakage is the metric that use to identify the efficiency of QA. As mentioned by demouser123, it's calculated against the number of slipped issue - the number of issue that found by customer by using delivered/released application

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