Appeal court clarifies when to seek an expert witness in litigation

How we decide to deal with trademark infringement depends on two factors: similarity or identity of trademarks and goods/services, and the likelihood of confusion. The existence of the latter risk is a normative question that should not be subjected to proof. The similarity of the signs and the risk of confusion are both subject to the court's independent assessment, from the point of view of the average consumer.

Expert opinions may be requested to verify connections between certain facts requiring special knowledge, or to draw conclusions. These differ from other evidence in that the purpose is not to establish facts relevant to the case but to provide the court with explanations on matters requiring special knowledge.

Whether the conditions for risk of confusion have been met should be assessed by taking into account the average consumer perspective for the goods or services in question. According to well-established case law, the average consumer model is abstract. It is the court’s task to assess likelihood of confusion as a condition for infringement of an international word mark.

Expert opinions in the spotlight

A recent judgment from the Poznań Court of Appeal sheds new light on the issue of doctrine and jurisprudence. In this case, the owner of a 3D trademark for a ghost-shaped snack wanted to prohibit a competitor from introducing a similar-shaped snack into the market. The court found, as an undisputed fact, that the defendant company used the character of a ghost in the production and trade of snacks. The relevant issue, according to the first-instance court, was whether the defendant’s use of a ghost-shaped snack might lead to confusion among consumers. The court indicated that such circumstances require knowledge of potential buyers’ decision-making mechanisms, which in turn requires specialised knowledge of advertising psychology. However, no research into this was conducted due to the categorical opposition of the parties.

In its verdict, the court of first instance stated that there was no evidence that the compared signs were likely to confuse consumers about the identity of the goods’ manufacturer. The court held that it was the plaintiff’s burden to prove that the defendant infringed on its right to the trademark. In the court’s view, failure to agree to undertake an expert opinion resulted in the claim being deemed unfounded.

The claimant appealed that judgment. The core of the appeal claimed that the district court erred in finding that an expert witness opinion was required to assess the likelihood of confusion. Moreover, the appellant emphasised that refusal to appoint an expert witness meant that the court had excluded the likelihood of confusion assessment altogether.

The Court of Appeal

On 27 May 2022, the Court of Appeal in Poznań issued a judgment (I AGa 229/21), stating that the appeal was well founded. As was correctly raised in the appeal, risk of confusion determinations are made based on the court's assessment, which is in turn based on the totality of the circumstances. The court considers the relevant consumer benchmark, taking into account indications of doctrine, case law, factual presumptions and life experience. Contrary to statements by the first-instance court, the appeal court indicated that an expert opinion is not always necessary to assess likelihood of confusion. However, it did leave room for doubt in its reasoning.

The appeal court reiterated that an expert opinion is unnecessary unless it proves useful in establishing risk. Expert evidence might also be necessary in cases where assessment of the likelihood of confusion requires special knowledge (ie, when an issue arises needing clarification that goes beyond the knowledge of someone not experienced in that particular field).

The court of first instance did not indicate which circumstances might require expert assessment. Only in general terms did it state that determining whether the defendant's snacks could have misled the public regarding their origin required knowledge of the decision-making mechanisms of potential consumer goods.

At that stage of examining the case, in the absence of any indication of likelihood of confusion, the appeal court’s opinion was that there were no grounds to question the district court’s position on the need for expert evidence. The parties however, even their expressed objection to such evidence, did not limit the district court in deciding to appoint expert evidence ex officio since, according to the court, the resolution of the case did require special knowledge.

On the one hand, this judgment confirms that assessing the likelihood of confusion is a normative issue and should not be solely based on expert opinion. On the other hand, it leaves the door open to request such an opinion if the risk of confusion assessment requires special knowledge.

Key takeaways

Admitting expert evidence to assess the likelihood of confusion carries the risk that the expert witness would be the one to resolve the case instead of the judge. The requirement of such opinion shall thus be diligently examined and will be requested only in exceptional circumstances. However, the decision-making mechanism of consumers may well be the primary issue in a trademark infringement case. Does that mean an expert witness will be necessary in each case? This would lead to a distorted risk of confusion assessment by the court. Moreover, it would prolong court cases that have already been going on for many years. As a rule, we believe that the risk of confusion should be assessed by the judge, by taking into account the model average consumer perspective of the goods or services in question.


This is an insight article whose content has not been commissioned or written by the WTR editorial team, but which has been proofed and edited to run in accordance with the WTR style guide.

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