Data Governance & Editorial Standards

The MasterBrain: Data Integrity Protocol

GreenCalculus runs a single canonical data layer — the MasterBrain — that supplies every calculator on the platform with emission factors, global warming potential values, and grid intensity figures. The protocol below describes how that data layer is updated, traced, version-stamped, archived, and disclosed.

The 30-Day Update Rule

GreenCalculus commits in writing to updating all affected emission factors and GWP values within 30 calendar days of a major publication event. The qualifying events are: a new IPCC Assessment Report cycle release (e.g., AR7 on publication), the annual DEFRA conversion factor update published each June, and the IEA Global Energy Review annual release.

The 30-day window is chosen deliberately. Shorter would not allow cell-by-cell verification against the source workbook before deployment. Longer would risk calculators serving stale data during an active reporting cycle, when practitioners are actively citing GreenCalculus values in their own GHG inventories. The window covers the time required to cross-check every changed value against the primary source, update the MasterBrain, propagate version stamps to affected pages, and publish the corresponding changelog entries.

Cell-by-Cell Provenance

Every entry in the MasterBrain carries a machine-readable _provenance block. This is not documentation aspiration — it is the live data structure, embedded against every fuel, every global warming potential value, and every grid intensity figure on the platform.

The provenance block records ten fields against each value: the source publication, the workbook filename, the tab name within that workbook, the row label, the row number, the column reference, the GWP basis applied (AR6 or AR5), the name of the person who sourced the value, the date sourced, and the verification status with an optional verification note. The structure below is a verbatim entry from the live MasterBrain for diesel — one of approximately one thousand entries audited to this standard.

'diesel' => [
    'factor'    => 2.57082,
    'unit'      => 'kg CO2e per litre',
    'scope'     => 1,
    'source'    => 'DEFRA_2025',
    'gwp'       => 'AR5_100',
    '_provenance' => [
        'source'      => 'UK Government GHG Conversion Factors 2025, DESNZ, June 2025',
        'workbook'    => 'ghg-conversion-factors-2025-full-set.xlsx',
        'tab'         => 'Fuels',
        'row_label'   => 'Diesel (average biofuel blend)',
        'row_number'  => 72,
        'column'      => 'D — kg CO2e (per litre)',
        'gwp_basis'   => 'IPCC AR5 GWP-100 (per Introduction tab Row 35)',
        'sourced_by'  => 'Jeremiah Say',
        'sourced_on'  => '2026-05-06',
        'verified'    => true,
        'verify_note' => 'Verified against full-set workbook directly.',
    ],
]

A practitioner who wishes to verify the diesel emission factor of 2.57082 kg CO₂e/litre can download the named DESNZ workbook, open the Fuels tab, navigate to row 72 column D, and confirm the figure directly against the source publication. The full provenance dataset is also exposed through a public REST endpoint at GET /wp-json/greencalculus/v1/gwp-values, allowing any practitioner, auditor, or downstream developer to query the data layer programmatically against the source attribution.

Version Stamping and Audit Trail

Every calculator, methodology page, and data page carries a version stamp at the top of the article body — for example, MasterBrain v2025.5 · DEFRA 2025 · IPCC AR6 GWP-100 — that links directly to the corresponding entry in the public changelog.

When the MasterBrain version bumps, every affected page receives a Major version bump simultaneously and its _gc_last_reviewed date is updated. This means a practitioner who used a GreenCalculus calculator in Q3 2025 to populate a corporate GHG inventory can return to the public changelog, identify the exact data version that underpinned the result, and reproduce the calculation if challenged during external assurance.

Archival and Reproducibility

GreenCalculus maintains a permanent, append-only archive of all prior MasterBrain versions. Legacy emission factors are never overwritten — they are version-stamped at the moment of supersession and preserved indefinitely so that historical calculations remain reproducible.

Every superseded value is retained with its original provenance block, the version in which it was retired, and a pointer to the entry that replaced it. The archive is queryable through the same REST endpoint as the live values, with the version parameter governing which snapshot is returned.

This policy applies equally to corrections (per §4 below) and to scheduled source updates (per the 30-day rule above). Even when a value is corrected because it was wrong, the wrong value is preserved in the archive — because removing it would silently invalidate every report built on it.

Dual GWP Basis Disclosure

GreenCalculus operates two concurrent GWP bases transparently — a practice rare among public environmental calculators. Both are declared in every calculator’s audit trail and every data export. Neither is hidden, and neither is treated as a silent default.

Practitioners choose the basis appropriate to their reporting framework. Both bases are published in full at our IPCC AR6 GWP reference table and applied within our published DEFRA 2025 emission factors.

Editorial and Quality Control Standards

GreenCalculus content is produced and reviewed against a three-layer model. Each layer has a defined role, a defined output, and a defined point of accountability.

Policy on AI Assistance

GreenCalculus is explicit about where AI tools are used and where they are not. AI tools may assist with formatting HTML, scaffolding code structure, and identifying candidate internal links between pages. All methodological decisions and all numerical outputs are hard-coded by Jeremiah Say from primary source documents.

Review Depth by Content Type

Different content types are subject to different review depths. The bar chart below shows the relative depth applied to each surface, followed by the full review matrix.

Independence and Conflict of Interest

No organisation can pay to have specific emission factors, preferred methodologies, or favourable assumptions featured on GreenCalculus. The factors used on this platform are those published by the relevant Tier-1 regulatory body — full stop.

GreenCalculus editorial policy

Independence

GreenCalculus is an independent technical resource. It is not a target-setting body — it does not set emissions reduction targets and does not validate corporate pledges, and is therefore distinct from organisations such as the Science Based Targets initiative. It is not a verification or certification body — it does not issue certificates, does not audit third-party emissions claims, and does not assert assurance opinions. It is not a consultancy — it does not provide bespoke paid advice. Its sole function is the impartial, accurate implementation of existing global standards into accessible calculation tools.

No pay-to-rank

No organisation can pay to have specific emission factors, preferred methodologies, or favourable assumptions featured on GreenCalculus. The factors used on this platform are those published by the relevant Tier-1 regulatory body — DEFRA for the United Kingdom, US EPA for the United States, IEA for grid intensity, IPCC for global warming potentials. No commercial relationship influences the data layer or the methodology documentation. If GreenCalculus ever receives sponsorship or advertising revenue from a party with an interest in any specific emission factor, that relationship is disclosed separately in standard site disclosures and does not affect editorial or data decisions.

Revenue model transparency

GreenCalculus is supported by display advertising and is building toward premium API access for enterprise users who require programmatic access to the MasterBrain data layer. Neither revenue stream creates editorial conflicts. Advertisers do not influence content selection, content ordering, or the values published in the data layer. API consumers query the same data layer that all public users see — there is no premium-tier divergence in the underlying numbers.

Correction and Feedback Policy

The Errata Process

When an error is identified — whether through internal review, an external practitioner challenge, or a MasterBrain audit — the following six steps are taken without exception. No silent fixes; no exceptions.

The changelog entry is written before the corrected page is published. Any practitioner who subscribed to the changelog RSS feed at the time of the error will see the correction in their feed.

Worked example: the v2025.2 CH₄ correction

Every calculator that referenced the affected fields received a Major version bump, and the v2025.1 snapshot — including the incorrect 25.0 value — remains queryable through the archived REST endpoint for any practitioner reproducing a pre-correction calculation. See the corresponding changelog entry for the full attribution.

Technical Feedback Channel

A useful submission includes the URL of the affected page, the specific value or methodology step in question, and the source document being cited as authority for the proposed correction. Challenges are reviewed by Jeremiah Say. For general site enquiries unrelated to data or methodology, see the standard contact page.

Compliance Framework Alignment

GreenCalculus’s internal governance is modelled on principles drawn from two internationally recognised verification frameworks: ISO 14064-3 (the standard for verification and validation of GHG statements) and the GHG Protocol Corporate Standard. The principles below are not aspirational. They describe how the data layer, the editorial process, and the correction policy already operate today.

ISO 14064-3 Principles

GHG Protocol Principles

Citing GreenCalculus

Every published calculator and methodology page exposes the live MasterBrain version stamp at the bottom of the page. Cite that stamp in any disclosure (CDP, SECR, CSRD/ESRS, internal audit) so the reader can reproduce the exact calculation.

The homepage provides three ready-to-copy formats:

• ISO 690 — EU compliance default, recommended for CSRD/ESRS reports.
• APA 7 — corporate sustainability academia.
• Vancouver — life-cycle assessment and science journals.

If your house style requires a different format, three principles let you build it:

1. Always include the MasterBrain version (e.g. v2025.55). The version stamp pins the exact data layer the calculation ran against, even after subsequent updates.
2. Always include the access date. Combined with the version stamp, this gives a reproducible audit trail for any output.
3. Always include the URL — root-relative or absolute. Each calculator and methodology page is a stable permalink.

Errata and corrections to past versions are documented in the public changelog and follow our Correction and Feedback Policy above — superseded factors remain queryable indefinitely so historical reports stay reproducible without needing to rerun any calculation.

Current Data Version Status

The table below shows the current version of each data source in the GreenCalculus MasterBrain and its last verified date. This table is updated manually as part of the annual data update cycle and within 30 calendar days of any major publication event covered by the §1 update rule.