Analysing European and International Patent Citations : A Set of EPO Patent Database Building Blocks

This paper presents a preliminary set of European and international citation data tables designed to enable researchers to become familiar with the subject and undertake a range of analyses. It addresses analytical and statistical issues such as why citations from international searches and European searches should be combined; the calculation of citation lags; use of International Patent Classification (IPC) codes for grouping patents according to technology; treatment of references to Non-Patent Literature (NPL); and the notion that many publications, from different patenting authorities, covering the same invention can be cited. Differences between US and European citations are also discussed.