5. Problem‑solution approach 

In order to render the assessment of inventive step more objective, the EPO applies the so-called "problem-solution approach", which should be applied consistently.

In the problem-solution approach, there are three main stages:

(i)determining the "closest prior art", 

(ii)establishing the "objective technical problem" to be solved, and 

(iii)considering whether or not the claimed invention, starting from the closest prior art and the objective technical problem, would have been obvious to the skilled person. 

The EPO applies option GL/ISPE A13.08.1 of the Appendix to Chapter 13 of the ISPE Guidelines.