# L1 Coverage Audit — Adaptive Abuse Detection (C-prime)

Designs judged on RECOMMENDATION text only. Function over vocabulary; same standard for both.
[HARD] components: #4 (error-cost FP/FN explicit), #6 (adaptation/recalibration loop), #7 (anti-gaming/secrecy), #10 (independent review before/after hard action).

## Design X — d35

| # | Component | Status | One-clause reason |
|---|-----------|--------|-------------------|
| 1 | Hidden-attribute hypothesis | COVERED | Frames inference as "is this behavior consistent with abuse?" — a behavior class, not a vague bad-account label. |
| 2 | Signal / evidence channel | COVERED | Many weak behavioral + relational signals, chosen costly-to-fake for abusers / cheap for honest sellers. |
| 3 | Threshold and routing rule | COVERED | Staged routing: clear→pass, ambiguous→soft reversible handling, strong corroborated→hard restrict via review. |
| 4 | Error-cost profile (FP vs FN), explicit [HARD] | COVERED | Names both failures (going blind to adapters vs crushing innocents) as the same failure; falling confirmation = loosen vs rising overturn = tighten. |
| 5 | Base-rate / validation check | COVERED | Continuously checks flags vs two ground truths; retires signals whose predictive value collapsed; audits across segments. |
| 6 | Adaptation & recalibration loop [HARD] | COVERED | Core "close the loop" engine: rotate/refresh signals on confirmation drop, hold out a fresh signal, treat screen as decaying. |
| 7 | Anti-gaming / signal-secrecy [HARD] | COVERED | Moving, partly-private, rotated signal mix; notice "specific enough to respond to (without handing abusers a recipe)" — boundary set deliberately. |
| 8 | Notice and reason-giving | COVERED | Understandable notice stating the basis specifically enough to respond to. |
| 9 | Review / appeal path with remedy | COVERED | Real contest path: submit context/evidence, reviewer with authority to overturn and restore, response deadline. |
| 10 | Impartiality / independent review before/after hard action [HARD] | COVERED | Reviewer separate from flagging engine decides; hard actions route through review; "never let a restriction rest on an unexplained score alone." |
| 11 | Consistency standard | MISSING | No like-cases-alike / documented-distinctions standard articulated. |
| 12 | Proportional / reversible consequence design | COVERED | Soft reversible actions for ambiguous cases; hard restriction only on strong corroborated evidence. |
| 13 | Monitoring of both error directions | COVERED | Tracks confirmation rate (hidden FNs) and overturn rate (FPs) with comparable seriousness, feeding recalibration. |
| 14 | Privacy / data-minimization boundary | COVERED | Pool boundary (scoped to crossed risk surfaces, not blanket surveillance) + evidence standard bound logging; declined as separate regime but function present. |

**X totals: 13/14 covered. HARD: 4/4 covered. HARD missing: none.**

## Design Y — d31

| # | Component | Status | One-clause reason |
|---|-----------|--------|-------------------|
| 1 | Hidden-attribute hypothesis | COVERED | Abuse signatures named (fraud patterns, rapid high-value transactions from new payment methods); behavior-class inference. |
| 2 | Signal / evidence channel | COVERED | Account activity, payment history, user reports, traffic patterns listed as evidence channels. |
| 3 | Threshold and routing rule | COVERED | Four-tier staged routing (watch/investigate/flag-restrict/escalate) keyed to confidence, hard action reserved. |
| 4 | Error-cost profile (FP vs FN), explicit [HARD] | COVERED | Dual-metric: catch rate AND FP rate both tracked, "neither sacrificed for the other" — co-equal posture stated. |
| 5 | Base-rate / validation check | COVERED | Monthly base-rate check vs background abuse frequency; FP/FN held-out validation; scope check. |
| 6 | Adaptation & recalibration loop [HARD] | COVERED | Expects degradation, versioned rules, monthly re-validation + rollback, scheduled adaptation cadence — ongoing relearning. |
| 7 | Anti-gaming / signal-secrecy [HARD] | COVERED | Shows evidence category not exact algorithm "(which could be reverse-engineered)"; boundary between secrecy and contestability set deliberately. |
| 8 | Notice and reason-giving | COVERED | Transparent flagging reasons: user gets a summary of which signals triggered the action. |
| 9 | Review / appeal path with remedy | COVERED | Mandatory human appeal, reversible, wrongly-restricted unrestricted with explanation, logged/audited. |
| 10 | Impartiality / independent review before/after hard action [HARD] | COVERED | Human reviewer "different from the original detection system"; "flag is a proposal for review, not a final judgment." |
| 11 | Consistency standard | MISSING | No like-cases-alike / documented-distinction standard; wrong-flags reviewed for pattern but not a consistency rule across sellers. |
| 12 | Proportional / reversible consequence design | COVERED | Severity scales with confidence tier; appeal decisions reversible; warnings before restriction at low tiers. |
| 13 | Monitoring of both error directions | COVERED | Tracks catch rate, FP rate, appeal-reversal rate AND blinded false-negative miss rate separately. |
| 14 | Privacy / data-minimization boundary | MISSING | No data-minimization / collect-only-justified-signals boundary; surveillance bound not addressed. |

**Y totals: 12/14 covered. HARD: 4/4 covered. HARD missing: none.**
