Recent reviews and policy discussions of the various IP systems have consistently lamented the lack of hard data on the extent of the problem of infringement
, what it costs and whom it affects, how firms respond, and how successful existing systems for IP enforcement are. This is hardly a new problem: over the years uncertainty and issues of measurement have plagued attempts to assess the various IP systems, causing even the most rigorous assessors to throw up their hands and say, more or less, ‘we don’t know if it works’, whether ‘it’ be the patent system (Machlup 1958) or copyright (Breyer 1970).
Nevertheless, innovation and its promotion are important to all advanced economies, basing policy on statistical evidence is increasingly possible due to enhanced accessibility of data, and a great deal of effort has been invested into answering what questions we can about the effects of the IP system. It is opportune, therefore, to review where we are: what we know already, where the gaps in our knowledge lie, and what research could practicably be done to improve our knowledge. To this end, the authors have reviewed the literature concerning IP infringement and enforcement. One goal is to work out what we know already: that is, what research has already been done. But equally, the aim is to assist in identifying what exactly we want to know and whether it is possible to find out, in some reasonably objective way.