Defect removal efficiency

What it means

Defect removal efficiency, or DRE, estimates how effectively a process catches defects before users encounter them. A common form divides pre-release defects by total defects found in the same scope, including post-release discoveries. The metric only helps when scope, severity, and discovery windows are consistent.

Example

For a release, 80 defects are found before production and 20 after release. Under that definition, DRE is 80 percent. The team investigates the 20 escaped defects and the cost of the late discovery.

Limitations

DRE can look better when teams change reporting or delay production discovery. It does not measure defect impact, prevention, or customer harm. Avoid using it as a standalone quality score.

How to use the signal

Review escaped defects by impact and cause, because early discovery alone does not show whether the process prevented customer harm.

Weave can connect escaped-defect periods with changed files, review activity, and deployment rework. The defect system owns the calculation; Weave helps teams examine the engineering work around the result.