Edge-Case Coverage Gap Estimator
Production defects in wealth-tech features cluster in code paths that no synthetic household exercised. This calculator turns that intuition into a number: given the corpus you have and the feature you're shipping, expected defect rate per release. And the delta to close it.
What you walk away with
~40s · 5 inputs- An expected production-defect rate for the feature given the current corpus.
- The number of additional archetypes required to drive the rate to target.
- A linked Edge-Case Coverage Score assessment for the systemic view.
Inputs
How many distinct synthetic households exercise this feature's code paths today.
Wash-sale, AMT, RMD-aggregation, IRMAA-cliff, ITIN-filer, etc. Count distinct classes.
Default source: Per Edge-Case Coverage Audit Checklist; typical wealth-tech feature: 4-8
Estimated probability that a given release ships a material edge-case-driven defect. Above 20% is structurally weak; below 5% is audit-grade.
Total archetypes needed to drive expected defect rate to the target. Add this many minus the current count.
Expected defect rate under different edge-case class counts (e.g. as feature scope expands).
- Edge cases halved (smaller scope)0.0 %
- Edge cases as input (default)44.4 %
- Edge cases doubled (larger scope)72.2 %
FAQ
Doesn't this overstate defect rate at high edge-case counts?
It can. The model is linear in (classes × paths) but in practice some intersections are structurally empty (e.g. 'IRMAA' × 'young accumulator' has no realistic case). For features where many intersections are empty, the worksheet's coverage matrix gives a more accurate read.
Is the 1.5-per-intersection ratio universal?
Roughly. Compliance-touching features need more variants per intersection (closer to 2). Pure-internal features tolerate fewer (closer to 1). The default is the wealth-tech-feature median.