Understanding Defect Removal Efficiency (DRE)
How we calculate. DRE % = (pre-release defects ÷ total defects) × 100. The form uses the same arithmetic as the worked examples on this page. See our methodology and accuracy policy.
Real-world scenario: A typical Defect Removal Efficiency (DRE) case uses defects found before release 72 and total defects (pre + post release) 80. Enter the same figures below to reproduce the worked path.
What is Defect Removal Efficiency (DRE)?
DRE is a classic software quality metric: how effective was the team at finding and fixing defects before shipping? It complements defect leakage (what escaped).
- High DRE (e.g. 90%+): most defects caught pre-release
- Low DRE: weak early testing or late defect discovery
- Use the same window: one release or one quarter for both counts
The Formula
Worked Example
Common Use Cases
- QA effectiveness reporting: track DRE per release
- Process improvement: invest in phases with the weakest catch rate
- Shift-left programs: measure whether earlier testing raises DRE
Pro Tips
- DRE + leakage ≈ 100% when both use the same total and complementary numerators
- Weight severity in narrative reports even if the % is unweighted
- Do not game counts by hiding production tickets
Limitations: Defect Removal Efficiency (DRE) results are estimates for learning and QA planning—not contractual SLAs. Align definitions with your org’s quality glossary before executive reporting.
FAQ
Is DRE the same as test pass rate?
No. Pass rate is about executed tests that passed. DRE is about defects found before vs after release.
What if post-release defects are still being found?
Freeze a time window (e.g. 30/60/90 days after release) so totals stabilize for fair comparison.
Authoritative References
For software quality metrics definitions, consult established engineering sources:
- ISTQB — software testing glossary and practices
- ISO/IEC 25010 — systems and software quality models
- IEEE — software engineering standards