Inventors and invention processes in Europe: Results from the PatVal-EU survey

Abstract

Based on a survey of the inventors of 9017 European patented inventions, this paper provides new information about the characteristics of European inventors, the sources of their knowledge, the importance of formal and informal collaborations, the motivations to invent, and the actual use and economic value of the patents.

Introduction

This paper provides new information, not available from other sources, on the characteristics of the invention processes in Europe, and on the economic use and value of European patents. Our data are drawn from a survey (PatVal-EU, or PatVal for short) of 9017 patents granted by the European Patent Office (EPO) between 1993 and 1997, located in France, Germany, Italy, the Netherlands, Spain and the United Kingdom (hereafter “EU6”).

There is a rich literature on the measurement of innovation (for surveys see Griliches, 1990, Patel and Pavitt, 1995). Along with input data such as R&D expenditures and the human capital employed in research, patents have become the most common measure of innovation output (see Hall et al., 2001, for a survey). A convenient feature of patents is that they resemble invention counts.³ Moreover, they have been well documented, especially in recent years thanks to the extensive on-line information that can be conveniently organized into databases. Another advantage of patents is that they can combine different indicators. For example, patent citations have been used to measure their importance and economic value (Trajtenberg, 1990, Hall et al., 2005, Harhoff et al., 1999), or to describe the direction and geographical extent of knowledge flows among inventors and patent holders (Jaffe et al., 1993, Verspagen, 1997). Similarly, patent claims have been used to account for the scope of patent protection (Lerner, 1994).

However, patents also have shortcomings. They relate only to certain types of inventions, and there are vast differences across firms, industries and countries in the precision with which patents measure innovation output. Moreover, there is still ambiguity about what exactly patent indicators measure. For example, some studies have shown that patent citations are a noisy measure of information flows (Almeida and Kogut, 1999, Singh, 2005), particularly because many citations are added not by applicants, but by the patent examiners or just to avoid infringements (e.g. Harhoff et al., 2006, Alcacer and Gittleman, 2006). Also, Lanjouw and Schankerman (2004) show that it is hard to distinguish whether patent claims are a measure of patent scope, degree of protection or of value. Similarly, citations are correlated with several aspects of the patent, e.g. its legal robustness and not just with its value.

The patent data and indicators presently employed in the literature are drawn largely from patent documents. As a result, information not in the patent files is mostly unavailable. This implies that while certain aspects about patents or underlying invention processes have been studied extensively, we have little or practically no information for others. For example, we do not know much about the inventors, or the nature of the research or other processes that gave rise to the invention; we typically have no measures of the value of the patent other than the proxies that we can retrieve from the patent document; and we know very little about whether the patent is used or not, whether it is licensed, or whether it is further developed into a new product by the applicant.

The most natural way of collecting this information is through surveys. Griliches (1990) himself noted that patent surveys had not been undertaken for a long time. Since then, Scherer, Harhoff and Vopel conducted a patent survey in the US and Germany to explore the distribution of the economic value of patents (Scherer and Harhoff, 2000, Harhoff et al., 2003b). The Yale survey (Levin et al., 1987) and the CMU survey (Cohen et al., 2000) investigated the motivations for patenting of US firms. Cohen et al. (2002) presented survey evidence on the role of patents for diffusing information in Japan relative to the US. Arundel and Steinmueller (1998) used the Community Innovation Survey to look at patents as information channels in Europe. Meyer (2000) interviewed a group of European inventors of nanotechnology patents to understand the connection between their invention and the scientific research that they cite. Tijssen (2002) performed a mail survey amongst Dutch inventors to understand the contribution of science to successful technical inventions, and to test the validity of patent citations to scientific literature as indicators of science dependency. While these surveys provide new data, they have limited European coverage and are mostly biased towards large companies.

In order to overcome some of the weaknesses implicit in earlier studies, PatVal is a large-scale survey designed to be representative of the universe of patents in our EU6 countries. It covers all technological fields, deals with both for-profit and non-profit applicants, and collects information on small, medium and large business companies. In 2003, patents with the first inventor located in one of our EU6 represented 42.2% of all EPO patents, and 88% of the EPO patents whose first inventor was in one of the EU-15 countries. PatVal's main objective is to collect information about patents and the underlying invention process on issues that had not previously been explored in depth because of lack of information in the patent documents. It also provides new proxies for variables like knowledge flows or patent value for which the present measures are subject to the discussions noted earlier.

This paper is the first of a series of contributions based on the PatVal survey that explore these issues. It focuses on three areas: inventors; research collaborations and spillovers; use and economic value of the patents. In all of these areas, either the literature does not provide information on some relevant topic, or there is ambiguity in the existing measures, or the existing information is potentially incomplete. The three central sections of this paper discuss the PatVal data that fill some of these gaps. They all start with a brief discussion of the existing literature.

Section 2 describes the survey and the data collected through the PatVal questionnaire. Sections 3 Who are the European inventors?, 4 Collaborations, spillovers and sources of knowledge, 4.1 Sources of knowledge spillovers, 4.2 The role of collaborations in the production of inventions, 4.3 Geographical proximity and exchange of knowledge among inventors, 4.4 Sources of knowledge in the invention process, 5 The use and value of EPO patents are the central sections on the three topics above. The final section concludes and summarizes the results. Appendix 1 describes the methodology employed to carry out the PatVal survey. Appendix 2 provides our definition of the uses of patents. Appendix 3 describes our test for assessing the inventors’ bias in their answers about the patent value.