Validation is an independent review of a project before monitoring begins: does the PDD comply with the methodology, and are the baseline and additionality justified? Verification is a review of results already achieved: has the actual emission reduction for the monitoring period been confirmed? Validation answers the question “was the project designed correctly?”, while verification asks “did it really deliver the claimed effect?”
Regulatory framework
- ISO 14064-3:2019 — requirements for the validation and verification of greenhouse gas statements; confirmed by ISO in 2024.
- ISO 14065:2020 — requirements for the bodies that perform validation and verification.
- ISO 14064-2:2019 — requirements for the projects themselves, against which the validator checks.
- Program rules (Verra, Gold Standard, the Article 6.4 mechanism) — additional requirements for accreditation and procedures.
The same ISO 14064-3 also applies to corporate reporting — see Inventory verification under ISO 14064-3.
How validation and verification differ
| Parameter | Validation | Verification |
|---|---|---|
| When | Before project registration | After each monitoring period |
| What is checked | PDD, baseline, additionality, monitoring plan | Monitoring report, actual data |
| Nature | Assessment of whether the forecast is well founded | Confirmation of historical data |
| Result | Validation opinion, registration | Verification opinion, issuance of units |
How the review works
- Planning. The verifier assesses risks and sets the level of assurance and materiality.
- Document review. PDD, calculations, monitoring report, primary documents.
- Site visit. Inspection of equipment and meters, interviews with staff.
- Data sampling. Recalculating some of the values from the primary documents through to the final tonnes.
- Findings. Requests for corrections and clarifications; the project owner responds and makes the corrections.
- Opinion. Positive, qualified or negative.
Common findings
- The calculation cannot be reproduced: the spreadsheets contain manual edits without explanation.
- Monitoring data do not match the monitoring plan in frequency or source.
- There is no evidence that the meters were calibrated.
- Emission factors were taken from a different version of the source than at validation.
- There is no clear change history: nobody knows who changed the baseline or when.
Independence of the reviewer
The main requirement for a verifier is the absence of a conflict of interest. An organization cannot review its own project or a project in which it has an interest. This is required by ISO 14065:2020 and program rules, and it is worth keeping in mind as early as when you choose a validation and verification body.
How it works in the platform
- The MRV contour is still in development and is marked “Soon” in the platform: it does not yet include climate projects, monitoring reports or validation and verification procedures. The platform does not replace an opinion from an accredited body.
- You can already prepare your data for review. In Data entry, consumption for each facility is entered month by month, invoices, certificates of completion and photos of meter readings are attached to the records, and every record shows the methodology applied — making it easier to trace a value from the primary document to tonnes.
- The year's “Change history” shows who changed what and when — an answer to the common finding about unexplained edits. A closed facility year is read-only, and only the administrator can reopen it.
- The administrator creates the annual company report in PDF and DOCX covering all facilities: before creating it, the platform checks data completeness, and any remaining gaps are listed in the report. Read more in the article on closing the year and the annual report.
Frequently asked questions
Can the same body perform both validation and verification?
This is determined by the program rules: whether the two roles can be combined and whether a different body is required for certain project types. Check the rules of the chosen program and regulatory documents.
What is the level of assurance?
It is the degree of confidence the verifier has in the opinion: reasonable or limited. The level required to issue carbon units is set by the rules of the specific program.
How long does verification take?
It depends on the size of the project, the quality of the data and the number of findings. A well-prepared document package and a reproducible calculation shorten it considerably.