4.3 Examination of evidence 

When evidence is submitted, the first thing to establish is what fact is being asserted, and then whether that fact is relevant to the decision. If not, the assertion is no longer considered and the evidence is not examined further. If the asserted fact is relevant, the next point is whether the submitted evidence proves it.

When evidence is examined, since theThe EPC says nothing about how the outcome of taking of evidence must be assessed, and so the principle of free evaluation unfettered consideration of evidence applies (E-IV, 4.1). This means that the content of evidence and its significance for the proceedings are assessed in the light of the particular circumstances of each individual case (e.g. time, place, type of evidence, position of witness in firm, etc.). The principle of free evaluation of evidence unfettered consideration also means that EPO departments are empowered to evaluate evidence submitted by the parties in any appropriate manner, or indeed to disregard it as unimportant or irrelevant. In particular, it has to be decided on a case-by-case basis when a particular piece of evidence is sufficient.

When deciding whether an alleged fact is accepted, the division may use the criterion of the "balance of probabilities", which means that it is satisfied that one set of facts is more likely to be true than the other. The more serious the issue, the more convincing the supporting evidence must be (see T 750/94). For example, if a decision might result in revocation of the patent in a case concerning alleged prior use, the available evidence has to be very critically and strictly examined. In particular, in the case of alleged prior use for which little if any evidence would be available to the proprietor to establish that no prior use had taken place, the division has to cede to the stricter criterion close to absolute conviction, i.e. beyond any reasonable doubt (see T 97/94).

When parties make conflicting assertions, the division must decide which evidence is the most convincing. When taking a decision, the division must be convinced that the alleged fact is true after taking all evidence into account. If it cannot establish which allegation assertion is right true on the basis of the evidence put forward, it must decide on the basis of the burden of proof, i.e. against the party bearing that burden but unable to prove its point convincingly.