ADR 019 Derived Binary View from Quantitative Metrics

ADR-019: Derived Binary View from Quantitative Metrics

Status: Accepted Date: 2026-05-16 Deciders: Michael Zargham Related: ADR-004 Quantitative Certification Outcome; ADR-007 Scope as First-Class RDF Resource; Quantitative Outcomes; Certification Predicate; Design Spec

Context

The Zargham 2026 paper, in its TDD framing, characterizes the RTM certification predicate as binary — the RTM is complete or it is not. v0.1's primary certification outcome is quantitative (see ADR-004 Quantitative Certification Outcome) because institutional adoption requires the gradient. Yet some downstream consumers — CI pipelines, dashboards, contractual sign-offs — want a single pass/fail signal. The question is whether v0.1 produces the binary view as a separate first-class outcome or derives it from the quantitative metrics against a configurable threshold. See Design Spec §4.5 and Certification Predicate.

Decision

flexo-rtm v0.1's binary certification view is derived from the quantitative metrics against a configurable threshold (per scope, per claim type, per aspect). A cert run produces the quantitative coverage matrix; the binary view applies the configured thresholds and emits pass/fail. The thresholds are part of the cert run configuration (scope + profile + thresholds — see ADR-007 Scope as First-Class RDF Resource and ADR-016 Composable SHACL Profiles); a cert artifact records both the quantitative metrics and the threshold-evaluated binary outcome.

Consequences

Positive

• Reconciles paper's TDD framing with industrial reality: institutions get the binary outcome the paper describes, but produced by an explicit, configurable threshold rather than implicit definition
• Threshold transparency: every cert artifact records the thresholds used; reviewers can see why a cert is binary-passing and what would have to change for it to fail
• Per-scope and per-aspect thresholds let safety-critical scopes set 100% while exploratory scopes set lower thresholds, without parallel binary-predicate definitions
• Forward-compatible with downstream-analysis paths (per ADR-032 Methodology Agnosticism as Foundational Axiom): an adopter who runs topological analysis as a downstream-analysis mode (see ADR-003 Topological Framework Documented as Future Work) can compose the closure predicate with the threshold-derived binary; adopters running SLSA, GSN, ARP4754A, or in-house analyses compose their own predicates on the same threshold-derived foundation

Negative / Tradeoffs

• Threshold-setting is a governance question per scope; institutions have to decide and document their thresholds
• The "TDD pass/fail" semantics of the paper is not literally what v0.1 implements — v0.1's binary is threshold-derived, which is more nuanced; bridging documentation required

Neutral

• The binary view is always a projection of the quantitative model — never a parallel computation that could disagree

Alternatives Considered

• Pure quantitative (no derived binary): Emit only coverage percentages and gap reports; let downstream consumers derive their own binary signals. Rejected: forces every consumer to define their own threshold mechanism, defeating the institutional-consistency story. A cert artifact should record a binary signal alongside the metrics so that contractual sign-offs and CI gates have a stable interpretation point.

Implementation Notes

• Cert run configuration declares thresholds as part of the run inputs (alongside scope and profile); thresholds are per claim type per aspect
• Analysis layer (oracle/src/oracle/analysis/) computes the quantitative coverage matrix; the cert-artifact builder applies thresholds and emits the binary view
• Cert artifact format records: (a) the quantitative coverage matrix, (b) the threshold configuration used, (c) the threshold-evaluated binary outcome per claim type per aspect, (d) the overall cert pass/fail (typically the AND of all threshold evaluations within the scope)
• See Certification Predicate for the canonical predicate semantics and threshold composition

References

• Design Spec §4.5 (Derived Binary View), §4.6 (Threshold Configuration)
• Certification Predicate — the canonical predicate semantics
• Quantitative Outcomes — the underlying quantitative model
• ADR-004 Quantitative Certification Outcome — the primary outcome this derives from
• ADR-032 Methodology Agnosticism as Foundational Axiom — the threshold-derived binary is flexo-rtm's; downstream-analysis paths compose their own predicates on top