How do I verify whether my supplier's data is correct?

The method behind the figure is the first check, not the figure itself

Whether a supplier's data is correct can primarily be verified by examining how that figure was derived, not the figure in isolation. Article 39 of the ESPR (Regulation (EU) 2024/1781) establishes as a standard for test, measurement and calculation methods that they must be reliable, accurate and reproducible. A supplier providing a value — energy consumption, a percentage of recycled material, a repairability score — should be able to substantiate that value with a method that produces the same result upon repetition and that aligns with the prescribed or accepted standards for that product category. Article 40 adds a second criterion: it is not only about how the measurement was taken, but also whether the product was designed in such a way that it behaves differently during a test than during normal use. Both articles are written as requirements for those producing the data, and precisely this requirement provides the basis for testing supplier data: not "is this figure correct", but "was this figure derived in a sound, reproducible manner, under representative conditions".

For test results and calculations, not for every supplier claim

Articles 39 and 40 concern the manner in which test results, measurements and calculations underlying environmental product information are derived — such as energy consumption, durability, repairability or substance content that ultimately appear in the product passport. They do not concern the reliability of a supplier as a business partner in a broader sense: not payment behaviour, delivery reliability or contractual arrangements regarding who is liable if data later proves to be incorrect. They also say nothing about data that are not test or calculation results, such as a warranty period, a type designation or a serial number — other provisions of the ESPR or of the delegated regulation applying to the relevant product category apply to these. Those seeking a way to assess the overall reliability of a supplier will therefore find no basis for this in these two articles; those specifically wanting to know whether a supplied measurement value was derived soundly will.

The precise test method per product category is not yet fixed everywhere

Articles 39 and 40 form part of the ESPR itself, which provides the general framework. The specific method by which measurement and calculation must be carried out for a particular product category follows from a delegated regulation per product category. For the majority of product categories, it has not yet been determined which method that will be precisely and when it becomes mandatory — this varies by category and is published separately. Until a delegated regulation for a product category is adopted and applicable, there is therefore no mandatory prescribed test protocol under the ESPR to assess supplier data against precisely. The standard from Article 39 — reliable, accurate, reproducible — does apply as a starting point, but the detailed test procedures for these categories are still lacking.

How supplier data can be tested in practice

In practice, this starts with requesting the substantiation behind a figure: which standard, which test protocol or which calculation method was used, and not only what the outcome is. A next step is to check whether that method complies with what is prescribed for the product category, if a delegated regulation already exists for it, or otherwise with a recognised and common method in the sector. After that, it is worthwhile to ask whether the test result was obtained under conditions that are representative of normal use, and not under conditions that deviate from it — that is precisely the point that Article 40 addresses with the prevention of circumvention. Requesting underlying test reports or calculations, instead of only a summarised final figure, makes it possible to assess reproducibility. And recording the source and the method used per data point makes the whole thing traceable — something that is also necessary when those data are processed in a product passport.

Where this follows from: Article 39 and 40 of the ESPR

This approach follows directly from the text of the ESPR: Article 39 (test, measurement and calculation methods) requires reliable, accurate and reproducible methods as the basis for product information, and Article 40 (prevention of circumvention and deterioration of performance) requires that a product does not perform more favourably under test conditions than under normal use. Both articles can be consulted in Regulation (EU) 2024/1781, as published on EUR-Lex.

Whoever now collects supplier data for a product passport can record those two questions — which method was used, and is it representative of normal use — alongside each supplied data point, and request and retain the underlying documentation as soon as it is available.

Where this is based on

The regulation itself is on EUR-Lex. We provide references for each claim; you do not have to take our word for it.

What you must do concretely

What is expected of you

Demonstrating that data is correct

A product passport contains data that comes from somewhere: from own production, or from a supplier who supplies a component or material. Article 39 of the ESPR (Regulation (EU) 2024/1781) concerns the test, measurement and calculation methods used to determine whether a product meets the requirements. For a company with 10 to 100 employees, this means in practice that not only the outcome counts — a figure on weight, origin, recycled content percentage or lifespan — but also how that figure was arrived at. A supplier providing a percentage of recycled material uses a method to do so. That method does not need to be included in the passport itself, but it is something that can be asked about at the moment a given data point is called into question.

Preventing figures that are correct on paper but not in practice

Article 40 of the ESPR concerns preventing circumvention and performance degradation — situations in which a product performs differently under test conditions than in normal use. This article is primarily directed at manufacturers and their own products, but the thinking behind it is relevant to anyone taking over data from another party: a figure that is correctly measured can still give a distorted picture if the measurement conditions do not match normal use. For a company that purchases components and assembles them into its own product, this means that a supplied figure is not only checked for "is this true", but also for "is this representative".

Recording where a data point comes from

What comes through in both articles is that traceability matters. A data point in the passport must be traceable in practice to a source: a test report, a supplier declaration, a certificate. This is not a question of distrust towards the supplier, but of building your own file. In the question which data you must request from your product suppliers there is therefore also the question of how that data is substantiated — not only what is being delivered, but also how that has been demonstrated.

Where things go wrong in practice

A few situations come up repeatedly with companies working with multiple suppliers.

The figure is taken over without a source document. A supplier sends an Excel file with material data, but no underlying test report or declaration. As long as nothing goes wrong, this goes unnoticed. During an inspection or following a complaint from a customer, there is then no substantiation — only a figure that was once passed on.

The test method is not the same as that intended in the regulations. A supplier tests in a way that is common in its own sector, but does not align with the method relevant for the product category in question according to Article 39. The data is then factually not incorrect, but not comparable with what is expected elsewhere in the chain.

Components from different suppliers are combined without distinction. For a product made up of components from multiple batches, sometimes one average figure is used instead of figures per component. If you work with a supplier for multiple product categories — or conversely with multiple suppliers for the same component — you encounter this here: see also the situation in which multiple suppliers supply the same component.

Data from a subcontractor is not checked separately. When a supplier itself works with a subcontractor for a specific component, it is sometimes assumed that the supplier has already verified that data. This is not automatic. For the data requested from a subcontractor the same attention to source should be given as with a direct supplier.

When importing from outside the EU, it is assumed that the data already complies with European methods. An importer who sources products from outside the European Union sometimes receives test results that have been drawn up according to a standard other than that in common use in the EU. This plays a role in the import of products from outside the European Union, where the question of who supplies which data and on what basis gains additional weight.

What you can document

A number of matters can be documented with relatively limited effort, and make it considerably easier to justify a data point afterwards:

The source document per data point — the test report, measurement report or the calculation underlying a stated value, kept separately per supplier and per component.
The test method used, so that it can later be verified whether this aligns with what is customary for the product group.
A declaration from the supplier on the accuracy of the supplied data, possibly combined with an agreement on updating if a production method changes.
Contractual agreements on the supply and substantiation of data, included in the purchase contract. How this can look is shown in the recording of the supply of digital product passport data in a purchase contract.
A confidentiality agreement, for situations where a supplier is only willing to share underlying data under certain conditions — see a confidentiality agreement with the supplier on product passport data.
A file per product group, showing who supplied which data point and when it was last checked, so that when a supplier is changed it is clear which data points need to be reassessed — relevant in the change of supplier during use.

This type of recording does not prevent a data point from ever proving to be incorrect, but it does make it clear that reasonable effort has been made to prevent this — and that makes a considerable difference when a data point is called into question.

This is not legal advice. This page provides general information about the regulations that this platform concerns. We do not know your situation. If you are in doubt about your own case, consult a lawyer or the competent supervisory authority.

Written with AI on the basis of the sources above, checked by a human on 2026-08-22. Is something incorrect? Let us know — corrections are given priority.