Threshold Versioning Register¶
Audit artifact — instantiates Adaptive Threshold Recalibration
The system of record for every threshold in force — its value, rule, rationale, approval, scope, and rollback trigger — so a boundary is never a mystery number.
Threshold Versioning Register is not an act of changing a threshold — it is the ledger that makes every threshold and every past change accountable. Its defining role is to be the single source of truth: for each boundary in the system it holds the current value, the action rule it feeds, the rationale and evidence behind the last change, who approved it and when, the scope it applies to, and the rollback trigger. Every revision appends a new version rather than overwriting the old, so the history is reconstructible. Where its siblings decide and deploy thresholds, this mechanism records them — turning a set of scattered magic numbers into an auditable, reproducible, reversible catalog.
Example¶
A bank's model-risk function keeps a threshold register. An auditor asks why the transaction-fraud model's escalation cutoff is 0.82. The register answers without anyone reconstructing it from memory: entry shows the live value (0.82), the routing rule it drives, the champion/challenger evidence that justified the last change, the model-risk committee's approval date, the scope (retail cards, EU region), and the rollback trigger (revert to 0.88 if the false-positive rate exceeds a set limit for two weeks). The prior version (0.88) is still on record with its own rationale, so the full lineage of the boundary is visible. The register didn't choose or ship 0.82 — but it is why the choice is now defensible and, if it goes wrong, cleanly reversible.[n1]
How it works¶
The distinctive artifact is one versioned entry per threshold, append-only: a change never edits history, it adds a new version linked to the review, test, and rollout that produced it. Each entry carries the fields that make a boundary accountable — value, rule, rationale, evidence, approver, scope, rollback — so the record answers "what is it, why, who said so, and how do we undo it?" without side channels. It is deliberately passive machinery: it produces no threshold and expresses no preference, but every other mechanism in the set writes its outcome here.
Tuning parameters¶
- Granularity — one entry per threshold or per system; finer is more auditable but heavier to maintain.
- Required fields — which metadata is mandatory (rationale, evidence link, rollback) before a change can be recorded.
- Immutability policy — strictly append-only versus editable; append-only preserves lineage but grows.
- Change-control workflow — who may write an entry, and what approval a new version requires.
- Linkage — how tightly entries link to the review, test, and rollout artifacts that produced them.
When it helps, and when it misleads¶
Its strength is accountability made structural: it lets anyone reconstruct why a boundary sits where it does, reproduce a past state, and reverse a change cleanly — indispensable when thresholds govern consequential decisions. Its classic misuses are two. A write-only register nobody consults gives the appearance of governance with none of the substance. And a register of backfilled rationales — entries written after the fact to launder a decision already made — is worse than none, because it dresses a fait accompli as due diligence. The discipline is to require the rationale and evidence at change time, and to make the register something people actually read before touching a boundary.
How it implements the components¶
threshold_version_registry— it is the versioned catalog of active and historical thresholds; the mechanism's core.audit_trail_and_rationale— each entry records why a change was made, the evidence, the alternatives, and the approver.current_threshold_rule— it holds the live boundary and the action rule attached to it as the authoritative statement of what is in force.
It does not diagnose drift or choose a new value (recalibration_rule) — Champion / Challenger Threshold Test, Risk Score Threshold Recalibration, and the review siblings do — nor does it deploy a change (rollout_and_guardrail_plan), which Staged Threshold Rollout owns.
Related¶
- Instantiates: Adaptive Threshold Recalibration — it is the record-keeping substrate that makes recalibration accountable and reversible.
- Consumes: the outcomes of Champion / Challenger Threshold Test and Staged Threshold Rollout — the decisions and deployments it records.
- Sibling mechanisms: Staged Threshold Rollout · Champion / Challenger Threshold Test · Risk Score Threshold Recalibration · Policy Threshold Update · Diagnostic Cutoff Revision
Editorial Notes¶
Form Classification¶
Form family: Record, Log & Register
Rationale: Threshold Versioning Register operates as a persistent ledger, log, register, or case record that preserves history and traceability because it the system of record for every threshold in force — its value, rule, rationale, approval, scope, and rollback trigger — so a boundary is never a mystery number.
Independent corroboration: The frozen evidence defines Threshold Versioning Register as 'The system of record for every threshold in force — its value, rule, rationale, approval, scope, and rollback trigger — so a boundary is never a mystery number', so its operative form is Record, Log & Register.
Review outcome: Independent reviewer agreement; high confidence.
Origin Attribution¶
Primary origin: Law & Governance
Origin pattern: Cross-disciplinary synthesis
Present-day reach: Universal
Rationale: The defining operation is: The system of record for every threshold in force — its value, rule, rationale, approval, scope, and rollback trigger — so a boundary is never a mystery number. In the law_governance lineage, that operation is specifically evidenced by authoritative or primary work that requires controlled contract files recording clauses, approvals, deviations, decisions, and their authoritative history. This makes law_governance the best historical origin, while the retained alternates document contributing methods and later applications rather than being mistaken for coequal origins.
Related originating lineages:
- Accounting & Auditing — accounting_auditing supplies a historically relevant parallel or contributing practice for the defining operation—The system of record for every threshold in force — its value, rule, rationale, approval, scope, and rollback trigger — so a boundary is never a mystery number—but the evidence does not make it the best primary lineage.
- Computer Science & Software Engineering — Computer science and software-engineering practice supplies a parallel or contributing lineage for the mechanism's defining operation: the system of record for every threshold in force — its value, rule, rationale, approval, scope, and rollback trigger — so a boundary is never a mystery number.
- Library & Information Science — Library and information-science stewardship supplies a parallel or contributing lineage for the mechanism's defining operation: the system of record for every threshold in force — its value, rule, rationale, approval, scope, and rollback trigger — so a boundary is never a mystery number.
- Organizational & Management Science — Organizational management's coordination, workflow, and capability tradition provides a formative adjacent lineage for the same threshold versioning register operation.
- Public Administration & Policy — Public administration, policy implementation, and program oversight supplies a parallel or contributing lineage for the mechanism's defining operation: the system of record for every threshold in force — its value, rule, rationale, approval, scope, and rollback trigger — so a boundary is never a mystery number.
Review resolution: The blind reviewers disagree on primary lineage (accounting_auditing versus law_governance), so I adjudicated the mechanism rather than inheriting either label. The defining operation is: The system of record for every threshold in force — its value, rule, rationale, approval, scope, and rollback trigger — so a boundary is never a mystery number. In the law_governance lineage, that operation is specifically evidenced by authoritative or primary work that requires controlled contract files recording clauses, approvals, deviations, decisions, and their authoritative history. This makes law_governance the best historical origin, while the retained alternates document contributing methods and later applications rather than being mistaken for coequal origins. The cited Federal Acquisition Regulation Part 4 directly supports the mechanism-specific operation and its disciplinary lineage. I retain all independently explained historical alternates without a numeric cap. origin_mode=cross_disciplinary_synthesis records how the mechanism arose; domain_reach=universal separately records how broadly it can now be applied.
Encyclopedia synthesis: The exact catalogued form synthesizes established practice rather than reproducing a single standard historical label.
Review outcome: Researched adjudication after independent review; high confidence.
Sources consulted:
Notes¶
The register is the substrate the rest of the archetype writes to: reviews, tests, and rollouts all deposit their result here. That makes it low-glamour but load-bearing — its value is realized only if entries are written at decision time and consulted before the next change, not reconstructed for an audit after the fact.
[n1] Model-risk management guidance (for example the U.S. interagency guidance known as SR 11-7) emphasizes documentation, versioning, and clear ownership of model components so decisions can be reviewed and reproduced. A threshold register applies that documentation principle to decision boundaries specifically. ↩