# INVERSION CLASS COVERAGE

**Scope:** The four-class taxonomy that structures coverage checking and the saturation guard that governs per-class stopping. Coverage is per claim, per class -- NEVER run-aggregated.

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## The four pre-registered classes

**IC-1 -- Boundary-Condition Inversion.** Conditions under which the claim collapses: subgroups, dosages, durations, populations, settings, measurement windows. Authentic skeptic: methodologist or subgroup analyst. Query satisfies IC-1 when it reasons about a specific boundary ("populations over 65 where enrollment criteria excluded frailty screening") rather than a generic negation.

**IC-2 -- Alternative-Explanation Inversion.** Confounders, measurement artifacts, selection effects, common-cause structures, framing effects that produce the same confirmatory evidence without the causal claim holding. Authentic skeptic: causal-inference methodologist or epidemiologist. Query satisfies IC-2 when it names the alternative and searches literature that confirms OR rules it out.

**IC-3 -- Replication-Failure Inversion.** Direct replication failures, adjacent-setting failures, contradictory primary studies, retracted work, registered-report null findings. Authentic skeptic: replication-crisis researcher. Query satisfies IC-3 when it targets replication venues, preprint servers flagged by replication projects, or adjacent-literature contradictions -- not a confirmatory search with "failure" appended.

**IC-4 -- Frame / Construct Inversion.** Alternative operationalizations, framing-effect literature on the claim's terms, definitional disputes. Authentic skeptic: measurement-theory scholar or construct-validity researcher. Query satisfies IC-4 when it surfaces literature under a *different* operationalization, not under a synonym.

Novel inversion modes surfaced mid-run go to the Surprise Register as taxonomy-review candidates, processed under the closest existing class for the current run.

## Coverage check (D2)

Coverage per claim requires each of IC-1..IC-4 to be either:
- exercised by at least one query whose scratch-artifact rationale articulates the class-specific skeptic reasoning, OR
- documented non-applicable, with the non-applicability reason logged to the Search Ledger (e.g., IC-3 non-applicable when no prior replications exist for a genuinely novel claim -- but the absence of priors is itself surfaced).

A claim with fewer than all four classes covered-or-documented is NOT defensibly closed. Run-level "coverage averages" are meaningless and forbidden.

## Saturation guard K

Saturation per class fires when the most recent K queries in the class each return either zero accepted sources OR sources that map to a disconfirmation category already surfaced earlier in this class for this claim.

- K = 3 for IC-1, IC-2, IC-3.
- K = 2 for IC-4 (construct space is narrower).
- Runaway ceiling = 8 per class; exceeding it is a meta-anomaly (inversion space wider than taxonomy admits).

**K is a guard against premature closure. K is NEVER a quota.** The Ledger must never cite "ran K queries" as the stopping cause; it must cite the specific disconfirmation categories observed and the consecutive null-or-known runs. Uniform K counts across claims regardless of complexity is a hidden-quota signal for Phase 9 evaluator audit.

## What this reference does NOT do

It does not specify queries. It specifies the coverage surface and the saturation shape. Query content is reasoned per claim from the skeptic frame in `AUTHENTIC_INVERSION_DOCTRINE.md`.
