Workiva Carbon is introducing an update to the Hybrid calculation method for Scope 3 Categories 1 (Purchased goods and services) and 2 (Capital goods). This update ensures that calculations using this method are transparent and auditable, using only CDP disclosures that meet a certain quality and coverage threshold, of relevant, disclosed supplier data. This new V2 methodology is applied to data from CDP disclosures submitted in 2025.

This change empowers you to take greater ownership of your supplier emission factors with enhanced visibility into the underlying source data.

Why this matters

Incomplete or erroneous activity data introduces risk. Workiva Carbon’s goal is to provide a highly auditable, GHG Protocol-aligned methodology, with data quality controls to mitigate risk. The new V2 methodology provides several key improvements compared to V1:

- Data quality threshold: Organizations are only included if their disclosures meet a minimum quality threshold for emissions and revenue data. This minimum threshold includes a requirement of disclosed Scope 1, 2 and a minimum of Scope 3 Category 1 (given this category is largest for most organizations) and at least 4 additional upstream Scope 3 Categories. 

- Enhanced transparency: You can now view the raw CDP disclosure data (Revenue, Scope 1, 2, and upstream Scope 3), and the factor calculation directly within the platform before choosing to adopt a supplier factor.

- Methodological alignment: V2 includes a supplier's full Scope 1, 2, and all reported upstream Scope 3 emissions, ensuring alignment with best practices.

- Inflation adjustment: V2 automatically adjusts for inflation when your transaction year differs from a supplier’s disclosure period.

- Elimination of proxies: V2 does not perform any "gap-filling" or proxy functions should disclosure data be missing or of poor quality. If an organization does not meet our data quality thresholds, it is excluded to ensure supplier factors are auditable and representative of reported data.

What’s changing

As someone who uses the Hybrid method V1, you have control over how and when you transition to V2.

Version control by reporting year

You can select which Hybrid methodology version to use for each reporting year. Your historic or complete reporting years are set to V1 by default. To learn how to select V2, follow the steps under “Update to V2” below.

- Historical consistency: Your reporting years starting before January 2026 default to V1 to maintain your historical consistency.

- Mandatory upgrade: All reporting years starting on or after January 2026 will automatically use the V2 methodology.

- Updates to V2 are one-way: Once a reporting year is updated and saved to V2, it cannot be reverted to V1 to ensure the integrity of your reported data.

Supplier mapping and dataset changes

With the introduction of the V2 methodology and improved data quality controls, some organizations available in V1 have been excluded from the V2 dataset to mitigate data quality risks and ensure supplier factors are auditable.

- Existing supplier mappings: Your current V1 mappings will remain. 
- - If a mapped supplier is also in the V2 dataset then no action is required. However, you now have transparency of the disclosure data and supplier factor calculation; it’s advised to review this for all existing mappings to ensure mapped supplier factors are still best suited for your inventory.
- - If a mapped supplier is not in the V2 dataset, you will see a warning icon. The V1 supplier factors will continue to be used when a reporting year is set to use V1, but will fallback to the spend-based calculation methodology (if mapped to a commodity) when it is set to V2.

- New supplier mappings: All new or updated supplier mappings must be selected from the V2 dataset.

- Mapping limit: You can map your suppliers to up to 100 CDP organizations. Mapping multiple suppliers to the same CDP organization counts as 1 mapping. This is a contractual limitation that CDP imposes on technology partners.

Update to V2

To benefit from the significant improvements in the V2 methodology and dataset, it’s recommended to update your historic reporting years from V1 to V2 and recalculate. You can request an impact assessment detailing what will change if you decide to update. 

1. From Carbon Home, click Measure, then Purchases.

2. Go to Settings.

3. Find the setting for Supplier mapping: Hybrid methodology version.

4. Select the reporting years you want to update from V1 to V2

5. Click Save.

6. Select the reporting years that you want to recalculate using v2.

7. Click Recalculate.

When you update a reporting year from V1 to V2, you get:

- Increased accuracy: V2 factors are built on the latest 2025 CDP data and include more comprehensive Scope 3 boundaries, and improved data quality.

- Fallback to spend-based: If a previously mapped V1 supplier did not disclose to CDP in 2025 or failed the V2 quality threshold, the system will fall back to the spend-based, or other alternative method for that supplier in reporting years set to V2.

Recommended actions

1. Review your settings: Follow the steps under “Update to V2” above  to see which version is applied to your reporting years.

2. Evaluate V2 for historic reporting years: Consider updating recent historic years to V2 to benefit from higher data integrity. 

3. Audit your mappings: Check your Supplier Mapping page for warning icons. If a supplier is no longer available in V2, determine if you want to retain the legacy V1 mapping for previous years or move to a spend-based approach. Review the CDP disclosure data and supplier factors for your existing mappings without warnings, and ensure that they meet your quality standards.

4. Confirm new supplier factors: For all new mappings, click Adopt emission factor after reviewing the disclosure details.

Note on Auditability: While you can view raw CDP data in-app to support audits, contractual terms prevent the downloading of raw CDP disclosure datasets. Use the PGS Audit File to see which methodology version was used for every calculation.