For every international application, the EPO as ISA issues either an International Search Report (ISR) and a Written Opinion of the International Searching Authority (WO-ISA) under Chapter I PCT or, in exceptional cases, a Declaration of Non-Establishment of International Search Report and a WO-ISA indicating that the ISA is not required to perform a search or cannot perform a meaningful search (see points 223 ff).
The WO-ISA provides the applicant with a preliminary, non-binding opinion on the issues of novelty, inventive step and industrial applicability. This allows the applicant to assess, already at the search stage, whether to proceed directly to the national/regional phase or to file a demand under Chapter II PCT in order to overcome objections raised in the WO-ISA and possibly receive a positive IPER. However, before taking a decision on filing a demand for international preliminary examination, applicants are advised to consider carefully the information regarding the usefulness of the procedure under Chapter II PCT (see points 295 ff).
Source: http://www.epo.org/applying/international/guide-for-applicants/html/e/ga_c_i_1.html
Date retrieved: 30 December 2018