PCT International Search and Preliminary Examination Guidelines
2.01 This chapter provides a brief, introductory overview of the international search stage. A complete discussion of the procedure at the international search stage is provided in Parts II and IV of the Guidelines.
2.02 The objective of the international search is to discover the prior art which is relevant for the purpose of determining whether, and if so to what extent, the claimed invention to which the international application relates is or is not novel and does or does not involve an inventive step. In some cases the International Searching Authority is not required to establish a search for some or all of the claimed subject matter, either because the scope of the claims is too uncertain or the application covers excluded subject matter (see Chapter 9) or else more than one invention is claimed (see Chapter 10).
2.03 At the same time as establishing the international search report, the search examiner establishes a written opinion The written opinion has the primary objective of formulating a preliminary and non-binding opinion on the questions of whether the claimed invention appears to be novel, to involve an inventive step (to be non-obvious) and to be industrially applicable. A secondary objective is to identify whether there appear to be any defects in the form or contents of the international application or any significant and pertinent issues as to the clarity of the claims, the description, and the drawings, or the question whether the claims are fully supported by the description.
2.04 It is essential that the search and the written opinion are carried out according to the same criteria which are used during the international preliminary examination. The search may also report on some material which may not strictly be relevant to novelty and inventive step, as detailed below in paragraph 2.10.