The objective of the international preliminary examination is to formulate a preliminary and non-binding opinion on the questions whether the claimed invention appears to be novel, to involve an inventive step and to be industrially applicable.[Art. 33(1); Rule 43bis.1(a); ]

The PCT does not define what is meant by "invention", but Rules 39 and 67 contain a list of subject-matter for which the ISA or IPEA is not required to carry out an international search or an international preliminary examination, respectively (see also GL/PCT‑EPO B‑VIII, 2). The Agreement between the EPO and WIPO in relation to the functioning of the EPO as an International Authority under the PCT indicates the subject-matter which the EPO is not required to search or examine, and according to its Art. 4 and Annex C the discretion not to search or examine is exercised by the EPO as ISA and IPEA only to the extent that such subject-matter is not searched under the provisions of the EPC, specifically Art. 52(2) EPC, Art. 52(3) EPC, Art. 53(b) EPC and Art. 53(c) EPC.[Art. 34(4)(a)(i); GL/ISPE 9.02; 9.15; OJ EPO 2017, A115; OJ EPO 2018, A24; ]