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Defect Removal Efficiency

Definition

The defect removal efficiency (DRE) gives a measure of the development team ability to remove defects prior to release. It is calculated as a ratio of defects resolved to total number of defects found. It is typically measured prior and at the moment of release.

Calculation

To be able to calculate that metric, it is important that in your defect tracking system you track:
  • affected version, version of software in which this defect was found. 
  • release date, date when version was released
DRE = Number of defects resolved by the development team / total number of defects at the moment of measurement. 

Dimensions

It should be possible to monitor Defect Detection Percentage in following dimensions:
  • Affected version
  • Priority

Presentation

DRE is typically measured at the moment of version release, the best visualization is just to show current value of DRE as a number.

Example

For example, suppose that 100 defects were found during QA/testing stage and 84 defects were resolved by the development team at the moment of measurement. The DRE would be calculated as 84 divided by 100 = 84%