2.1 Completeness of the search 

A European search is essentially a thorough, all-encompassing search carried out to a high quality standard. Nevertheless, a search of this kind cannot always be 100% complete, in particular because all information retrieval systems, however they are operated, are inevitably imperfect. The search is carried out in a way that minimises the risk of overlooking complete anticipations of any claims, or other highly relevant prior art. Given the sheer amount of material on less relevant prior art that is available in the document collection, it is acceptable if not all of it is found (however, see also B‑III, 2.3). For limitations of the subject-matter searched, see B‑VIII.

The scope of the international search is defined in Art. 15(4) PCT, which states that the ISA must endeavour to discover as much of the relevant prior art as its facilities permit and must, in any case, consult the minimum documentation specified in Rule 34 PCT. It follows from this definition ("as much … as its facilities permit") that international searches must be equivalent in scope to a European search and must be carried out to the same high quality standard. This means that, if the EPO carried out the international search or the supplementary international search, it does not need to draw up a supplementary European search report and its international search report can replace the European search report (Art. 153(6) EPC, see OJ EPO 2010, 316, and OJ EPO 2011, 616; see also B‑II, 4.3).