Calculation and evidence
Draft · methodology 0.1.0-draft
Declare the boundary for every result
Section titled “Declare the boundary for every result”For every result, publish: reporting perspective, included and excluded activities, lifecycle modules, factor sources and vintages, geography, allocation rules, uncertainty and data quality, treatment of biogenic carbon, treatment of recycling credits, gross versus comparative results, and the applicable greenhouse-gas indicator. Do not claim full ISO 14040/44 or ISO 14067 conformance without formal review.
Factor registry
Section titled “Factor registry”A factor record carries: factor_id, source_name, source_url, dataset, version, publication_date, effective_date, geography, sector, activity_type, numerator_unit, denominator_unit, gwp_basis, gas_coverage, lifecycle_boundary, value, uncertainty, license, last_reviewed, deprecated and superseded_by.
This specification does not publish emission-factor values. Factors come from sources an implementation licenses and selects for its jurisdiction, reporting period and purpose. Sources to evaluate independently include GHG Protocol guidance, national emission-factor datasets, grid-intensity datasets, waste-treatment models (with correct counterfactual interpretation), environmental-declaration program operators and their product category rules.
Evidence grading
Section titled “Evidence grading”| Grade | Definition | Example |
|---|---|---|
| A | Independently verifiable primary evidence | Scale ticket plus facility acceptance |
| B | Direct observation with internal traceability | Meter reading, invoice, geotagged work record |
| C | Derived from documented primary data | Quantity takeoff with documented conversion |
| D | Documented model estimate | Estimate line mapped to a generic product intensity |
| E | Unsubstantiated assumption | Generic proxy without job-specific evidence |
This grading is a TRP proposal, not an external assurance grade. Each result SHOULD expose data_grade, evidence_coverage, uncertainty_range when supportable, reviewer, reviewed_at and methodology_status. Do not convert a grade into a statistical confidence percentage without a defensible calibration method.
Uncertainty
Section titled “Uncertainty”Track measurement error, factor variability, model and proxy error, product-mapping confidence, missing data, scenario assumptions and declaration comparability separately. Prefer ranges or scenario sensitivity to a single opaque accuracy score. A portfolio total MUST disclose the share of impact based on grades A to E and the major excluded categories.
Reproducibility
Section titled “Reproducibility”Recalculation with pinned factor and methodology versions MUST yield identical output.
Audit package
Section titled “Audit package”A reproducible report exports: source record identifiers and hashes, evidence manifest, immutable event history, selected product and declaration references, factor registry snapshot, calculation method and version, unit conversions, scope boundary, allocation and deduplication decisions, baseline and selected scenario, human approvals, exceptions, generated-at timestamp and report hash. Restrict personal data according to authorization.
Reporting economics
Section titled “Reporting economics”Claims outcomes are constrained by coverage, indemnity, approved scope, loss-adjustment expense and policyholder consent. TRP does not guarantee that a lower-impact product is a permissible LKQ substitution. Report estimate delta, approved settlement delta, actual paid delta and lifecycle cost projection separately. Never present modeled savings as realized insurer savings.