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Calculate · Assess & Decide · Engineering

Defect removal efficiency

Defect Removal Efficiency from pre-delivery vs escaped defect counts, with an optional per-phase breakdown.

You receive: A reviewed DRE calculator + the passing test report, run on your defect counts.

Part of Ship MVP

Example

A sample of what this play produces. Your result is generated for your inputs.

85Dre

By phase

PhaseDre
code review35
gate (tests, lint, build)61.54
preview verify40
Inputs
Internal defects
34
Escaped defects
6
Per phase
yes
Phases
PhaseRemovedEscaped
code review1426
gate (tests, lint, build)1610
preview verify46
Zero division policy
undefined

Arithmetic recomputed against the tasks.py compute_defect_removal_efficiency oracle, 2026-08-08, on an illustrative release cycle for a code-first product like STUD's platform (the defect counts are illustrative, not published figures). Of 40 defects total, 34 were removed before delivery and 6 escaped to production, so overall DRE is 34 / (34 + 6) * 100 = 85.0. Per phase, each row divides that phase's removed count by removed plus the defects that slipped past it: code review caught 14 of the 40 it saw (14 / 40 * 100 = 35.0), the gate caught 16 of the 26 that reached it (16 / 26 * 100 = 61.54, rounded to 2 decimal places), and preview verification caught 4 of the remaining 10 (4 / 10 * 100 = 40.0), leaving the 6 that escaped. With defects present, the zero-defect policy (undefined) never fires.

Opens soon

Cost50 credits
ProtectionSpent when the run starts · returned only if STUD is at fault

STUD opens runs for everyone soon, on every play at once.

Scope of the check

What's verified: STUD verifies the calculator computes Defect Removal Efficiency on held-out cases: internal defects / (internal + escaped) * 100, an optional per-phase breakdown, and your chosen zero-defect policy (undefined reports null, perfect reports 100). STUD does NOT verify the defect counts are real or complete, nor judge whether the resulting efficiency is good enough; it checks the arithmetic on the counts you provide.

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