Burden of Proof

“The person who benefits from a claim should not outsource the work of disproving it. ”

Sustainability debates often begin in the wrong place. A company makes a broad claim and asks critics to prove it false. A supplier declares compliance and requires an affected worker to demonstrate abuse. A programme reports impact and challenges outsiders to produce a better explanation.

The practical burden of proof has been transferred from the actor with the information and benefit to the person with the least access to either. The burden of proof identifies who must do the evidentiary work. In courts, regulation and science, the standard varies with the decision and its consequences.

Sustainability claims are not all legal proceedings, but the underlying principle remains useful: the actor advancing a factual proposition should normally possess a reasonable basis for it before asking others to rely upon it. European consumer law makes this more than an editorial preference.

Article 12 of the Unfair Commercial Practices Directive requires Member States to give courts or administrative authorities power, where appropriate, to require traders to provide evidence for factual claims. If the evidence is not furnished or is insufficient, the claim may be treated as inaccurate. The rule does not require consumers to reverse-engineer a marketing statement before the trader has to support it.

The 2024 Amsterdam District Court judgment concerning KLM's former environmental advertising illustrates the point. The court found that a number of statements relied on vague and general environmental benefits or presented an overly favourable picture of measures such as alternative aviation fuels and reforestation. The issue was not whether every initiative was imaginary.

It was whether the evidence justified the overall impression that the communication created.

A burden of proof should be proportionate to the strength and consequence of the claim. A narrow statement about recycled content may be supported by controlled supplier records and testing. A claim that a product is environmentally beneficial requires a broader life-cycle basis. A claim of impact may require evidence about baseline, counterfactual, contribution, distribution and duration.

Stronger language creates a stronger evidentiary obligation. Future claims carry a particular burden because the promised condition does not yet exist.

Directive (EU) 2024/825 strengthens EU rules concerning environmental claims about future performance, including expectations for clear, objective and publicly available commitments supported by detailed and realistic plans, measurable time-bound targets and independent verification where the rules apply. Ambition is not evidence of feasibility.

The principle also matters inside supply chains. A farmer should not lose market access because a risk model cannot distinguish missing data from non-compliance. A worker should not have to prove retaliation through a mechanism controlled by the employer. Where an organisation's system creates the inference, the organisation should explain the data, threshold and route for challenge.

The burden should not fall automatically on the person affected by an opaque decision.

Burden of proof is not the same as demanding certainty. Most sustainability decisions are made under incomplete information. The relevant standard may be reasonable basis, balance of evidence, high confidence or precaution, depending on the consequence. The discipline is to state the standard and apply it consistently rather than lowering it for preferred claims and raising it for inconvenient findings.

The burden can also shift as evidence develops. A credible allegation may require an organisation to investigate even when the affected person cannot access internal records. A supplier declaration may establish an initial fact until contradictory evidence appears. A verified result may justify confidence within its scope, while new conditions trigger reassessment.

Burden is part of a process, not a permanent privilege for one side.

For practitioners, the default should be simple: evidence should precede the claim. The claimant should define the proposition, assemble support, test alternative explanations and preserve the file before publication or decision. If the organisation cannot explain what would count as sufficient evidence, the claim is not ready. Asking the public to disprove it is not transparency; it is an evidentiary shortcut.

Practical application

Assign an evidence owner and approval standard to every material claim and decision. Record who bears the initial burden, what evidence is required, when the burden may shift and what route exists for challenge. Match the standard to the breadth, consequence and audience of the proposition. For automated or risk-based decisions, provide affected people with the basis of the inference and a practical appeal route.

For public claims, maintain a dossier before publication and withdraw or narrow wording when evidence is unavailable, expired or contradicted.

Why it matters

Burden of proof determines whose uncertainty becomes whose cost. Poorly allocated burdens allow powerful actors to benefit from broad claims while workers, farmers, consumers and communities carry the difficulty of disproving them.

Common misconception

A sustainability claim is often treated as acceptable until someone proves it false. Objective claims require a reasonable evidentiary basis before they are made; the absence of an immediate challenge does not provide that basis.

Connections

Evidence concerns the material available. Substantiation links that material to exact wording. Environmental Claim and Greenwashing concern the impression created. Accountability determines who can challenge the claim, while Remedy addresses harm caused when the burden was wrongly allocated.

A question worth asking

Who currently bears the practical burden of disproving your strongest sustainability claims, and do they have access to the information needed to do so?

Selected references

European Union. 2005. Directive 2005/29/EC on Unfair Business-to-Consumer Commercial Practices, Article 12. European Union. 2024. Directive (EU) 2024/825 on Empowering Consumers for the Green Transition. District Court of Amsterdam. 2024. Fossielvrij NL v. KLM, ECLI:NL:RBAMS:2024:1512. Federal Trade Commission. 2012. Guides for the Use of Environmental Marketing Claims. ISEAL Alliance. 2025.

Sustainability Claims Good Practice Guide, Version 2. 0.