Reducing uncertainty in the patent application procedure insights from malicious prior art in European patent applications

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1 Please cite this article as: Sternitzke, C., Reducing uncertainty in the patent application procedure insights from malicious prior art in European patent applications. The R&D Management Conference, Risk and Uncertainty in R&D Management, Bremen, Germany, 4-6 July 2007, ISBN Reducing uncertainty in the patent application procedure insights from malicious prior art in European patent applications Christian Sternitzke 1 1 christian.sternitzke@tu-ilmenau.de Technische Universität Ilmenau, PATON Patentzentrum Thüringen, PF , Ilmenau, Germany and Universität Bremen, Forschungsgruppe Innovation und Kompetenztransfer, Wilhelm-Herbst-Strasse 12, Bremen, Germany Achieving patent protection for an invention is a costly procedure. The patenting process in front of the patent office itself is frequently associated with substantial uncertainty about the outcome. This paper aims to identify measures to reduce this uncertainty and increase efficiency in patenting by investigating so-called world patent applications in chemicals, pharmaceuticals, and biotechnology that were subsequently not granted by the European Patent Office (EPO). Examination reports of these documents were searched for that were regarded malicious for novelty or inventiveness of the patent application. The results from studying these provide several implications for patent applicants in chemicals, pharmaceuticals, and biotechnology: to reduce uncertainty in the patenting procedure, patent applicants should a priori search both patent and nonpatent literature thoroughly. Novelty is in many cases anticipated in patent literature. Nonpatent literature and, in particular, technological areas closely related to the application in many cases anticipate the inventive step. Furthermore, inventors and applicants were aware of a considerable share of malicious prior art, they frequently appear to overestimate both novelty and inventive step of their invention. During a further stage of the examination procedure, when the International Search Report for the world patent application is available, applicants seem to have a good chance that no more malicious prior art will be found in the subsequent examination when no are contained in the search report coded with X or Y. 1. Introduction Patent applications are filed frequently to appropriate the returns of successful and costly research and development (R&D) projects. The outcome of the patenting procedure is a granted patent providing the applicant with the right to prevent others from using the invention. On the way towards a granted patent there are several pitfalls inducing uncertainty about the outcome of the patent procedure in front of the patent office. Even though this topic is of high relevancy in practice, it lacks attention in scholarly literature. Uncertainty has been investigated in litigation trails and opposition procedures (e.g. Lemley, 2001; Harhoff and Reitzig, 2004; Sherry and Teece, 2004) or to estimate the optimal patent life time (e.g. Rafiquzzaman, 1987). This paper aims to identify how applicants can reduce this uncertainty at the patent office by exploring cited in patent examination reports that were regarded as malicious for inventiveness or novelty of the patent application and hence, prevented granting of the patent. In the patenting procedure, patent examiners analyze patent applications according to valid patent laws. This means that the invention needs to fulfill certain criteria such as novelty, the involvement of an inventive step (i.e. the invention may not have been obvious for the skilled 1

2 man in the art or in other words trivial), the invention must be commercially applicable. Several areas are excluded from patentability, such as algorithms, the treatment of the human or animal body, etc. Additionally, the application needs to comply with several formal standards, such as the format of the submitted application documents, fees have to have been paid, and the invention has to be fully disclosed so that the skilled man in the art can replicate what shall be protected. The latter point is one fundamental aspect of the patent system disclosure to stimulate innovation for legal protection that guarantees an appropriate return on investment of the underlying R&D effort. Hence, to obtain a granted patent, applicants have to comply with all these aspects. This paper focuses particularly on two issues mentioned above that play a crucial role in the patenting procedure: novelty and the existence of an inventive step. Patent examiners scan the relevant literature, mainly patents, in order to find prior art documents that anticipate the invention or give indication regarding the inventive step. In general, the examiner subsequently discusses the patent applications claims and cites relevant sources. As a consequence, both novelty and inventive step can be assessed through analyzing the contained in patent documents, a field known as (patent) citation analysis. Many papers have been published on patent, following the pioneering work of Narin and his colleagues (e.g. Carpenter et al., 1980, 1981; Carpenter and Narin, 1983; Narin et al., 1984, 1987; Narin and Noma, 1985; Narin and Olivastro, 1988). They all have in common that or citations analyzed originate from search reports or the cited section for instance in U.S. patent documents. It is well known that these are quite noisy due to different policies at the patent offices: In the United States, patent law requires applicants to submit a list with prior art that might be relevant. Frequently, examiners include these into the reference list. The European Patent Office (EPO) follows the policy to cite only a minimum number of (for a discussion, see Meyer, 2000; Mogee, 1991; Michel and Bettels, 2001; EPO, 2005). Thus, only a subset of all in patents is in fact relevant to assess novelty or prior art. These relevant can only be found in examination reports. For this paper therefore examination reports of the EPO were studied to elicit which exactly were malicious regarding novelty or prior art. Malicious in this case means that they were relevant prior art for some claims in the patent, not necessarily 100 percent of the claims contained therein. The patent documents studied were all patents filed via the World Intellectual Property Organization s (WIPO) Patent Cooperation Treaty (PCT). These so-called WO patent applications aimed at a variety of countries and therefore belong to particular important inventions. More specifically, these WO patent applications had to have the EPO as designated office, relate to the field of chemicals, pharmaceuticals, and biotechnology, and had to have failed in the examination procedure. To sum up, the explorative analyses in this paper address the following questions: What are the sources of malicious prior art in patents? How are novelty and inventiveness connected to these sources? Do applicants have the chance to discover relevant sources ex ante, or is this almost impossible because for instance these sources were published too shortly before filing the WO patent application? Were applicants ex ante aware of malicious prior art, and if yes, were these prior art documents highly relevant to assess novelty or inventiveness? Do malicious patent originate from the same technology field? Is it possible to predict the outcome of the examination procedure based on the International Search Report from WIPO search authorities? The paper is organized as follows: The second section explains the data basis for the analyses. Section three demonstrates and discusses the results as well as limitations. Conclusions and outlook for future research follow in section four. 2. The data The survey focused on PCT patent applications with the EPO as designated office that had failed during the European examination procedure. Failure could both have led to an official rejection of the patent application, or to withdrawal of the application through the applicant, which in practice frequently occurs when the patent office had communicated severe objections against the patent application. The sample was drawn from a set of PCT patent applications investigated in an earlier publication (see Sternitzke, 2007) that analyzed all PCT applications with priority dates from the first half of December 1996, in total 2,719 applications. Among them, 2,600 had the EPO as designated office, and after deleting sets with missing data, 2,564 applications remained. Among these 2,564 applications 171 belonged to the technology fields investigated, namely the organic fine chemicals; macromolecular chemistry, polymers; pharmaceuticals, cosmetics; and biotechnology, as defined via classes of the International Patent Classification (IPC) by DTI/OST. These 171 patent applications were searched in EPOLINE, the European patent register. 92 patent applications had to be excluded, either because no electronic file was available, the electronic file was incomplete, or no examination had taken place. A handful of patent examinations had to be excluded because either no proper examination could have been carried out due to obscurities relating to the priority date, or the prior art mentioned related to earlier, novelty destroying disclosures of the same applicant. The remaining 79 patent applications formed the basis for this paper. In many of the 79 patent applications, malicious prior art was not the only reason for failure. For further analyses, patent family and classification information was retrieved from the Derwent World Patents Index (WPINDEX) database via STN International. Where no information on the patent family s main class was available in WPINDEX, the first IPC class mentioned in the Esp@cenet database was chosen. In the case where inventor s were 2

3 analyzed, the full text of the WO patent applications was screened manually. Finally, when the WO document was in Japanese, the corresponding European patent application was screened. 3. Results and Discussion Of the 79 WO patent applications identified, 20 had failed in the examination procedure even though no malicious prior art was mentioned, neither regarding novelty nor the inventive step. Here obviously other objections by the patent office led to the rejection or withdrawal by the applicant. The remaining 59 WO patent applications contained both patent as well as nonpatent from the applicant, and only a subset was in fact regarded to be malicious by the examiner. Nonpatent mainly refer to scientific articles/publications, in many cases from prestigious journals, in a few cases also to books. Table 1 gives an overview about the 59 patent documents and the contained therein. 3.1 Sources of malicious prior art 80 percent of all patent applications under examination contained at least one malicious patent reference, thus patent literature plays a crucial role when searching for prior art. However, nonpatent literature may not be ignored: 59 percent of the patent applications contain at least one reference to nonpatent literature, and 20 percent contain nonpatent exclusively. Hence, a priori searches by applicants in chemicals, pharmaceuticals, and biotechnology hence need to focus on both. These results also underline the fuzzy border between science and technology: Is that what has been filed as patent application still technology or rather science? If it is the former, then the frequently cited statement that over 80 percent of all technical knowledge is only contained in patent documents (see Häußer, 1981; Fendt, 1988) would not be valid in these technological fields. The findings also suggest that if prior art of an invention that by nature is also commercially applicable is in fact publicly available (scientific) literature, that the knowledge contained therein and hence the literature is commercially valuable in itself. when taken together with other. Thus, a four level assessment was performed through manually screening the examination reports. It was found that about half of all WO patent applications contained both N and I coded and a quarter each only N and only I. Table 2 and 3 provide a more detailed overview about the results. In total, 125 patent were contained within the 59 examination reports, and 86 nonpatent. About two thirds of all patent relate to NX documents, signifying that these documents contained prior art that is malicious in novelty to at least one claim of the patent application. About a quarter of the patent refer to IX and IY documents each. In contrast, nonpatent contain fewer documents relevant for rendering novelty of claims obsolete; they seem to be more important to assess the inventive step. Checking for significance by means of a chi-square test, it was found Table 1. Distribution of contained in examination reports among patents and nonpatent. Distribution of a) Number of patent >=1 b) Number of nonpatent >=1 a) AND b) 23 (39%) Only patent Only nonpatent Total 47 (80%) 12 (20%) 59 (100%) 35 (59%) 24 (41%) 59 (100%) Table 2. Distribution of purpose. Type of reference Patent Nonpatent Total 125 (100%) 86 (100%) NX 80 (64.0%) 39 (45.3%) NY 2 (1.6%) 2 (2.3%) IX 35 (28.0%) 26 (30.2%) IY 29 (23.2%) 32 (37.2%) more than one entry per reference possible 3.2 Novelty and inventiveness in malicious prior art In a next step it was further investigated why these had been incorporated. Did they relate to novelty (coded as N) or the lack of the inventive step (coded as I)? In this context it was further assessed if the reference was malicious itself, or only together with other. This characterization can also be found in EPO or WIPO search reports: X relate to a document that is of particular relevance itself, while Y coding refers to documents that are particularly relevant Table 3. Chi-square test of the distribution of purpose Type of reference Number of Patent NX Observed Expected NY Observed 2 2 Expected Nonpatent 3

4 IX Observed Expected IY Observed Expected Total more than one entry per reference possible. p= that patents are significantly more utilized to assess novelty than nonpatent publications, but the latter are used significantly more than expected to evaluate the existence of an inventive step. So what the applicant had often considered being inventive was in fact the combination of various knowledge sources originating from both patent and, in particular, nonpatent literature, and combining these sources would have been obvious for the skilled man in the art. It should therefore be beneficial for inventors to study both types of documents thoroughly during the R&D phase, and for applicants to make sure when drafting the patent application that both knowledge sources had been searched extensively. 3.3 Availability of malicious prior art to applicants With the findings of the previous section in mind: Could applicants have been aware of the malicious prior art mentioned in the examination reports? Figure 1 provides an overview about the age structure of the. In each case, the publication year of the reference was counted The results show that more than 50 percent of the originate from the last four years. More than two-thirds were available at least one year prior to the patent application s priority dates. Those published after the priority date relate in the case of patent to patent applications that had been filed earlier at the EPO than the applications under consideration, i.e. they had an earlier priority date and thus were regarded as prior art. Obviously, the applicants could not have been aware of these documents. Surprisingly, examiners cited also articles that had been published after the priority date, in some cases even violating novelty. The examiners not always gave reasoning for taking these into account. However, in one case it was mentioned that the publications were very descriptive in nature. So it could be that even though these nonpatent had not been characterized as review articles in the Science Citation Index they might refer to various sources that are malicious in nature for the patent application, but were not cited individually in order to minimize the total number of in the examination report. Another phenomenon that can be observed in figure 1 is that referenced patents in general range back further than publications, which can be explained with data availability: patent documents are accessible more easily for a longer time period than nonpatent literature. So since many malicious were theoretically accessible for the applicant, the question arises if he (or his patent attorney formulating the patent application) was in fact aware of some malicious prior art. Comparing found in the full text of the patent application with of malicious prior art from examination reports (while controlling for patent family documents) reveals the answer: Yes, to a certain degree applicants knew about malicious prior art! Applicants were aware of 20 percent of all patent, and 31 percent of all nonpatent. Table 4 demonstrates that the applicant was aware of at least one malicious patent reference in 30 percent of all WO patent applications, and he knew about at least one malicious nonpatent reference in almost 50 percent of all cases. In 15 percent of all WO patent applications he was even aware of all malicious. Since applicants are less aware of patent, more extensive searches in patent databases seem to be appropriate. Since applicants know about a considerable part of malicious prior art, it appears that applicants can hardly assess if prior art is in fact malicious! 4

5 30,0% Patent References Nonpatent References 25,0% 20,0% share of 15,0% 10,0% 5,0% 0,0% τ+1 τ=0 τ 1 τ 2 τ 3 τ 4 τ 5 τ 6 τ 7 τ 8 τ 9 τ τ 15 publication years of patent in comparison to priority years of examined patent documents 16 τ 20 τ< 20 Figure 1. Age distribution of. Is there any difference between recognizing novelty or inventive step from the applicant s perspective? Table 5 answers this question: nonpatent known by applicants have a distribution that is, according to a chisquare test, not statistically significant from the distribution of unknown nonpatent. For patent, the situation is different: applicants know significantly more about that are malicious regarding the inventive step. This finding suggests that applicants encounter difficulties particularly in assessing if their work is inventive in nature or not. In other words, they overestimate their inventive skills! Another interpretation for this finding would be that, in particular with respect to malicious patent, the applicant intended to circumvent these prior art inventions, which obviously failed as far as the circumvention is patentable itself. 3.4 Search strategies for identifying malicious prior art application was compared with the IPC main class of the referenced malicious patents. To obtain a more detailed picture, the IPC was broken down in subclass (4-digits), group (7-digits) and main- or subgroup (full number). Additionally it was controlled for reference types such as novelty and inventive step. Results can be found in Table 6. Table 4. Patent applications were the applicant was aware of. Distribution of Total sample Applicant or attorney was aware of Number of patent >=1 Number of nonpatent >=1 Number of patents with malicious prior art some 47 (100%) 14 (30%) 35 (100%) 16 (46%) all 59 (100%) 9 (15%) How can the applicant ex ante improve his search strategy for patent literature? Since the IPC plays an important role in patent searches, the IPC main class of the WO Table 5. Chi-square test for the distribution of purpose among known and unknown from the applicant. Type of reference Number of Patent Nonpatent Unknown by applicant Known by applicant Unknown by applicant Known by applicant NX Observed Expected

6 NY Observed Expected IX Observed Expected IY Observed Expected Total more than one entry per reference possible. For patents: p=0.002; for nonpatent : p= Table 6. Overlap of patent with IPC of citing WO application IPC Total patent Type of reference NX NY IX IY 4-digit 87 (69.6%) 56 (70.0%) 1 (50.0%) 25 (71.4%) 24 (82.8%) 7-digit 66 (52.8%) 44 (55.0%) 0 (0.0%) 18 (51.4%) 17 (56.6%) full 36 (28.8%) 28 (35.0%) 0 (0.0%) 11 (31.4%) 5 (17.2%) Total 125 (100%) 80 (100%) 2 (100%) 35 (100%) 29 (100%) 6

7 About 70 percent of all malicious patent originate from the same 4-digit IPC class as the WO application under examination, 50 percent from 7-digit, and less than a third is assigned to the same full IPC class as the WO application. Thus a major share of malicious prior art can be found just by searches in classes were the applicant expects his application to be assigned to. Taking the reference types as a basis, 70 percent of all NX patent come from the same 4-digit IPC, about the equal amount from IX patent, and app. 83% from all IY patent. While about one third of all NX and IX patent originate from exactly the same IPC class, only 17.2% of all IY patent do. However, for the overall table, this finding proves not to be statistically significant in a chi-square test, but it indicates that combining knowledge from closely related fields instead of knowledge from areas further away, such as completely different IPC classes, frequently does not involve an inventive step and hence, is a risky patenting strategy. Table 7 supports this and sheds more light on this issue: Patent applications, particularly when coming from exactly the same IPC class, are more threading to novelty of the invention than questioning the inventive step. Applicants should take this in mind when searching prior art to ensure novelty and inventive step of their invention, and when performing searches to aid problem solving in R&D. 3.5 The International Search Report Last but not least the applicant has further possibilities to estimate the outcome of the examination procedure for WO applications after having filed the application. This can be accomplished on the basis of the International Search Report prepared by an international search authority. In total, 70 percent of all patent that were later considered to be malicious prior art had been mentioned in this report, and 57 percent of all nonpatent. The rest was discovered later in the examination procedure at the EPO. A statistically significant difference relating to the type of reference (novelty, inventive step) between patent and nonpatent as well as documents found before and after the examination procedure could not be found by means of chi-square tests (see Table 8). The International Search Report by WIPO authorities contains that are considered to be relevant for the application. As mentioned earlier, they are coded with X and Y when they particularly relevant for the invention, and with A if they relate to the technological background. Hence, the latter should less likely turn out to be malicious prior art in the examination procedure. This assumption can in fact be confirmed in practice (see Table 9). Table 7: Share of reference types over IPC classes IPC Total patent in WO-IPC class Type of reference NX NY IX IY 4-digit 87 (100%) 56 (64.3%) 1 (1.2%) 25 (28.7%) 24 (27.6%) 7-digit 66 (100%) 44 (66.7%) 0 (0.0%) 18 (27.3%) 17 (25.8%) full 36 (100%) 28 (77.8%) 0 (0.0%) 11 (30.6%) 5 (13.9%) Table 8: Characteristics of malicious mentioned in the International Search Report and found later in the examination procedure Malicious Total Type of reference NX NY IX IY Malicious patent revealed in International Search Report Malicious patent revealed during examination procedure Malicious nonpatent revealed in International Search Report Malicious nonpatent revealed during examination procedure 88 (100%) 58 (65.9%) 1 (1.1%) 20 (22.7%) 18 (20.5%) 37 (100%) 22 (59.5%) 1 (2.7%) 15 (40.5%) 11 (29.7%) 49 (100%) 23 (46.9%) 1 (2.0%) 11 (22.4%) 12 (24.5%) 37 (100%) 16 (43.2%) 1 (2.7%) 15 (40.5%) 20 (54.0%) Percentages relate to the share of all malicious within the domain. Results from chi-square test: p patent =0.367, p nonpatent =

8 Table 9: Predicting malicious prior art from International Search Report results No malicious prior art found in examination procedure International Search Report contained neither with X nor Y International Search Report contained only with neither X or Y marks International Search Report contained at least one reference with either X or Y marks 13 (65%) No malicious prior art was found during examination procedure 7 (35%) Malicious prior art found during examination procedure 13 (72%) 5 (28%) Total 20 (100%) Total 18 (100%) Two thirds of the WO applications that did not fail due to malicious prior art in the examination procedure had an International Search Report where no reference was marked with neither X nor Y. The other way round, from those where the International Search Report contained neither X nor Y, examiners did not encounter malicious prior art for 72% of the WO applications. To conclude, these findings suggest that coding of in International Search Reports is a strong indicator of the subsequent success of the application in the examination procedure. However, due to the small amount of patent applications falling into this category, the results should be treated cautiously. 3.6 Limitations The analyses in this paper encounter several limitations. First of all, to demonstrate that some claims are not novel or inventive, European patent examiners need to show only as many as are necessary to prove that the claims are not patentable. Thus, only a subset of cited in search reports may be mentioned as malicious in the examination report, even though more documents from the search report might be malicious as well. Second, some patent examiners tended to not assess the inventive step when novelty of a claim was already rejected (e.g. see examination report of WO ). Others did not follow this policy (e.g. see examination report of WO ) and checked both novelty and inventive step. This might have led to an overestimation of the impact of novelty within prior art documents. Third, malicious prior art should also be available in examination reports to patent applications that were subsequently granted, but in this case they should only relate to a subset of claims contained in the patent application. Also including findings from these sources could broaden the statistical basis of the conclusions drawn in this paper. 4. Conclusions and Implications Developing technological innovations is a costly process. Protecting these innovations is also connected with substantial costs, such as the application fee at the patent office, drafting the text of the application, maybe with support from a patent lawyer, and, if the innovation appears to be particular valuable, substantial translation fees of the document. Only a granted patent provides the owner with the right to exclude others from using the invention. The outcome of the patent application process, however, is associated with a substantial amount of uncertainty. This paper addressed this issue and investigated WO patent applications in the field of biotechnology, chemistry, and pharmaceuticals aiming at a variety of countries worldwide that had failed at the European Patent Office. References to relevant prior art made by the examiners were analyzed. The results have several implications for patent applicants in these fields and can help increasing efficiency in patenting: To reduce uncertainty in the patenting procedure, patent applicants should ex ante search both patent and nonpatent literature with particular focus on documents that had been published recently, not only for drafting the patent application but also for R&D work in general. Nonpatent alone are accountable for about one third of all relevant. Since many claims were anticipated by publications, it appears that commercially valuable knowledge can also be found in such publicly available literature. It was revealed that patents play a crucial role to determine novelty. In many cases the inventive step underlying the WO patent application could be anticipated through patent documents from closely related technological subfields, i.e. from patent documents relating to the same 4-digit but not full IPC class as the WO application, or through combining several nonpatent sources. So the combination of knowledge from areas closely related to the patent application appears to involve a lower inventive step. Searches for knowledge sources for R&D projects as well as patent searches for drafting the application should take this into account. Another finding is that applicants or inventors were aware of malicious prior art in a major share of all WO patent applications. Thus inventors both overestimate novelty of their work as well as their inventive skills. During a further stage of the examination procedure, when the International Search Report for the WO application is available, applicants have a good chance that no more malicious prior art will be found in the subsequent examination when no were contained therein coded with X or Y. Future research should expand the scope of this survey to other technology fields as well. The impact of nonpatent literature as malicious prior art should for instance vary considerably here. It would also be of interest to investigate if other techniques such as Natural Language Processing (NPL), co-word analysis, etc. would be able to recognize if documents found by applicants are actually malicious in nature or not. Such kind of analyses 8

9 9 would be able to help save applicants further expenses during the granting procedure or ex ante help drafting the application accordingly. In this context it would also be worth questioning applicants and inventors about their perception of the they knew but that were subsequently recognized as malicious by the examiner. Was it more gambling on the application, or was the applicant rather seen as an alternative way to achieve the same means as drafted out in known (malicious) prior art? 5. Acknowledgements The author would like to thank Elke Thomae for valuable discussions on the subject. Narin, F.; Noma, E., (1985): Is technology becoming science? Scientometrics, 7, 3-6, Narin, F.; Noma, E.; Perry, R., (1987): Patents as indicators of corporate technological strength. Research Policy, 16, 2/4, Narin, F.; Olivastro, D., (1988): Technology indicators based on patents and patent citations. in: van Raan, A. F. J., Handbook of quantitative studies of science and technology. (1988), Amsterdam: North-Holland, Rafiquzzaman, M, (1987): The optimal patent term under uncertainty. International Journal of Industrial Organization, 5, 2, Sherry, E. F.; Teece, D. J., (2004): Royalties, evolving patent rights, and the value of innovation. Research Policy, 33, 2, Sternitzke, C., (2007): The international preliminary examination of patent applications according to the Patent Cooperation Treaty a proxy for patent value? Scientometrics, forthcoming. 6. References Carpenter, M. P.; Narin, F. (1983): Validation Study: Patent Citations as Indicators of Science and Foreign Dependency. World Patent Information, 5, 3, Carpenter, M. P.; Narin, F.; Woolf, P., (1981): Citation rates to technologically important patents. World Patent Information, 3, 4, Carpenter, M.; Cooper, M.; Narin, F., (1980): Linkage between basic research literature and patents. Research Management, 13, 2, DTI/OST. DTI/OST Technology group & IPC Subclass mapping, Technology%20Groups.doc, (27 June 2006). EPO. Guidelines for Examination, PART B CHAPTER IV SEARCH PROCEDURE AND STRATEGY, 3. Procedure after searching, 3.1 Preparation of the search report, b_iv_3_1.htm, (13 Oct 2005). Fendt, H., Technische Trends rechtzeitig erkennen. Harvard Manager, 10, 4, Harhoff, D.; Reitzig, M., (2004): Determinants of opposition against EPO patent grants-the case of biotechnology and pharmaceuticals. International Journal of Industrial Organization, 22, 4, Häußer, E., (1981): Mehr Innovation durch verbesserte Information. Ifo-Studien, Zeitschrift für empirische Wirtschaftsforschung, 27, Lemley, M. A., (2001): Rational ignorance at the patent office. Northwestern University Law Review, 95, 4, Meyer, M., (2000): Patent citations in a novel field of technology - What can they tell about interactions between emerging communities of science and technology? Scientometrics, 48, 2, Michel, J.; Bettels, B., (2001): Patent citation analysis. A closer look at the basic input data from patent search reports. Scientometrics, 51, 1, Mogee, M. A., (1991): International patent data for technology analysis and planning. Final Report. Center of Innovation Studies, Lehigh University, Bethlehem, PA (02-Feb-2005). Narin, F.; Carpenter, M. P.; Woolf, P., (1984): Technological performance assessments based on patents and patent citations. IEEE Transactions on Engineering Management, EM-31, 4,