Rating Contract & Maturity Model
TrackForge still tracks evidence maturity internally, but the current certificate-facing rating is the AAA-D leakage rating. Evidence maturity answers "what evidence do we have?" The rating answers "what leakage conditions are active under the declared methodology and scope?"
Three Separate Concepts
| Concept | Purpose | Example output |
|---|---|---|
| Evidence maturity | Describes the depth and provenance of the evidence packet. | Source counts, operator review, proof artefacts. |
| Leakage state | Describes deterministic taxonomy conditions. | Active, inactive, not applicable. |
| Rating event | Applies methodology-versioned materiality and aggregation rules. | AAA, AA, A, BBB, BB, B, CCC, CC, C, D. |
Keeping these concepts separate prevents two errors:
- Treating missing global-society checks outside the declared UK/US scope as "poor coverage".
- Treating source agreement as a substitute for leakage-taxonomy state.
- Treating PRS agreement binding or ISWC coverage as optional hygiene when they are declared workflow inputs.
Rating Event Inputs
Every production rating event pins:
- Methodology version and methodology hash.
- Taxonomy version.
- Workflow version.
- Jurisdictional scope.
- Subject ID and snapshot run ID.
- Agreement-binding and ISWC coverage summaries where in scope.
- Evidence packet hash or rating input hash.
- Leakage vector hash.
- Merkle root.
- OpenTimestamps proof state.
- Snapshot time.
Current Scope Boundary
The current direct workflow is UK/US. A catalogue should not be penalised for not directly checking societies outside that declared scope. If the scope changes, the methodology version and workflow version must change with it.
Maturity Is Still Useful
Evidence maturity remains useful for operator diagnostics and future expansion. It can explain why a leakage condition was found, how strongly it is evidenced, and what proof artefacts exist. It should not be presented as the public rating language unless it is explicitly labelled as a legacy or diagnostic field.
Portfolio Aggregation
Catalogue ratings aggregate track-level and pathway-level leakage state using methodology-versioned rules. The final formula must prevent severe defects from being averaged away by a large clean tail, and it must identify the material revenue pathways affected.
In particular, an otherwise clean catalogue should not remain AAA if a material share of PRS/MCPS-scoped works are not explicitly bound to client WACD agreements. ISWC gaps should also be weighted by pathway and materiality so identifier defects are visible without pretending every blank ISWC has the same commercial consequence.
Historical methodology versions remain comparable only when the comparison states the version bridge being used.