8.3.1 In general

Inventive step has to be assessed on the basis of the skilled person's knowledge before the priority or filing date (see T 268/89, OJ 1994, 50; T 365/89). The same level of skill has to be applied when, for the same invention, the two questions of sufficient disclosure and inventive step have to be considered (T 60/89, OJ 1992, 268; T 373/94, T 99/14, T 1861/16, see also chapter II.C.4.1 "The disclosure is aimed at the skilled person"). In T 694/92 (OJ 1997, 408) the board added that, although the same level of skill is applied for both Art. 56 and Art. 83 EPC 1973, the two starting points differ; for inventive step purposes, the skilled person knows only the prior art; for sufficiency of disclosure, they know the prior art and the disclosed invention.

In T 2039/18 the board found that the skilled person’s ability to reproduce an invention based on the information in the contested patent and common general knowledge was completely unrelated to whether its subject-matter was obvious to the skilled person in view of the state of the art. In an assessment of inventive step, the person needed not only to possess the appropriate ability: there also had to be a reason for the measure. This reason was one that should not be construed retrospectively (see chapter I.D.6. "Ex post facto analysis"). It was not justified in the board’s view to attach equal weight to the requirements of Art. 83 and 56 EPC in this context.