A study of Patent Thickets (1.31Mb) - UK Intellectual Property Office

A Study of Patent Thickets 17
2 Literature Review
In this section we review the current economic and legal literature touching on patent thickets.
This literature is very extensive and much additional detail can be found in the careful studies
undertaken by the Federal Trade Commission and the Department of Justice in the United
States (2003; 2007; 2011). This literature also overlaps with a broader literature on patents and
patent systems which is reviewed by Hall and Harhoff (2012) and WIPO (2011a) .
At the end of this section we also briefly review the literature on growth of small and medium
sized enterprises.
2.1 Patent thickets
In the introduction we discussed six factors that contribute to the growth of patent thickets.
Further, we note that self-reinforcing feedback effects cause patent thickets to grow in intensity
once they have emerged. In this section we first review the literature on the factors that contribute
to the emergence and growth of patent thickets in more detail, and then discuss possible
feedback effects. Finally, we summarize the literature on the effects of patent thickets on
competition and innovation.
2.1.1 Causes of Patent Thickets
In the introduction we noted the following six causal factors for the growth of patent thickets:
1. The strengthening and broadening of patent rights in the US and frequent use of
injunctions in some jurisdictions;
2. The cumulative nature of science and technology and a shift towards complexity in many
technologies;
3. Shifts in the degree of technological opportunity in various key technologies;
4. Strategic patenting by corporations and the assertion of patents by Patent Assertion
Entities (PAEs);
5. Lack of resources and misaligned incentives at patent offices dealing with the resulting
flood of patent applications;
6. Growth in trade of high technology products, leading to an increase in demand for
patents by foreign firms and to the spread of patenting trends from Japan and the United
States to other jurisdictions.
All of these factors contribute to the emergence and growth of patent thickets. But they are also
responsible for an unprecedented level of demand for patents at patent offices around the
world. This growth in demand can be seen as a sign of the increased globalization of innovative