Defect rejection and leakage ratio

There are number of test metrics that could be used to assess the quality of test execution for a project i.e. effectiveness of the testing team.

The two most important ones could be:

1. Defect leakage ratio – this refers to the number of defects that have been undetected during the project (SDLC) and ended up in production. These could be due to number of issues such as poor environment, functional testing coverage, missing or incorrect requirements.

The ratio can be determined with the following formula:
PD / (TD – RD) * 100
PD = Total number of defects found in production
TD = Total number of defects found during testing
RD = Total number of rejected/invalid/cancelled defects

• Defect rejection ratio

Defect rejection ratio refers to the number of defects that were raised that have been rejected divided by the total number of defects raised.
There are 3 main categories/types of rejected bugs: irreproducible, incorrect and duplicate bugs.

Ratio is formulated as follows:
(Defects Rejected as invalid by Development team / Total number of defects logged) * 100