Backward Citations Research Articles

Lens or Prism? Patent Citations as a Measure of Knowledge Flows from Public Research

This paper assesses the validity and accuracy of firms' backward patent citations as a measure of knowledge flows from public research by employing a newly constructed dataset that matches patents to survey data at the level of the R&D lab. Using survey-based measures of the dimensions of knowledge flows, we identify sources of systematic measurement error associated with backward citations to both patent and nonpatent references. We find that patent citations reflect the codified knowledge flows from public research, but they appear to miss knowledge flows that are more private and contract-based in nature, as well as those used in firm basic research. We also find that firms' patenting and citing strategies affect patent citations, making citations less indicative of knowledge flows. In addition, an illustrative analysis examining the magnitude and direction of measurement error bias suggests that measuring knowledge flows with patent citations can lead to substantial underestimation of the effect of public research on firms' innovative performance. Throughout our analyses we find that nonpatent references (e.g., journals, conferences, etc.), not the more commonly used patent references, are a better measure of knowledge originating from public research.

Analysis of the relationship between citation frequency of patents and diversity of their backward citations for Japanese patents

Conventional patent citation analyses have focused mainly on the presence of citation relationships, the number of patents cited by the subject patent, and the number of times the subject patent is cited by others (i.e., the numbers of backward and forward citations of the subject patent). However, most of them have not focused on patent classifications. Assuming that a patent based on a variety of technological bases tends to be an important patent that is cited more often, this study examines and clarifies the relationship between the diversity of classifications assigned to backward citations and the number of forward citations for Japanese patents. The results show notable differences in the number of classifications assigned to backward citations between the often cited and less frequently cited groups. It is considered that the diversity of backward citations can be utilized in the evaluation criteria for grouping that roughly identifies the often cited patents or eliminates a large part of less frequently cited patents.

Convergence indicator: the case of cloud computing

Convergence is a term that is often used to explain changes in contemporary society, and technological convergence has been an important source of technological innovation in industry. For this paper we adopted a microscopic approach to the question of measuring the level of technological convergence using patent-citation analysis. We developed a convergence indicator that shows the relative convergence degree of a patent. This indicator, which is based on backward and forward patent citations, can assess the extent of the level of convergence or universality. Finally, we conducted an empirical analysis of the cloud computing area using patent-citation analysis from a microscopic perspective.

Patent analysis for analysing technological convergence

PurposeFusion of new technologies and convergence has led to the emergence of new industries. This paper aims to present experiences of the concept of convergence from a patent citation analysis viewpoint. The main objective of the paper is to develop a tool for anticipating the emerging new industry segments.Design/methodology/approachThe patent analysis methods have been used to get an idea of the stage of new industry segment in the intersection of the paper and electronics industries. The authors distinguish self‐citations from external citations, and further divide citations into two groups: within the industry and beyond the industry. Backward citations are used to evaluate the spill‐overs between industries and forward citations are used to evaluate the significance of technology‐based industry transformation.FindingsThe recognized trends of the trajectory changes and growing overlaps of technological fields show indications for possible convergence between industries. Differentiating between external and self‐citations within and beyond industry citations helps to provide more comprehensive prospects of a future technology competitive environment.Research limitations/implicationsThis study evaluated technology development in converging environments. It would be a scientifically significant contribution if the novel patent analysis methods could be used effectively for creating understanding in advance about the technology development and industry convergences.Originality/valueThe presented patent citation methodology provides new insights into the analysis of industry evolution, technological innovations and business development related to converging industries and technologies.

Lens or Prism? A Comparative Assessment of Patent Citations as a Measure of Knowledge Flows from Public Research

This paper assesses the validity and accuracy of firms’ backward patent citations as a measure of knowledge flows from public research by employing a newly constructed dataset that matches patents to survey data at the level of the R&D lab. Using survey-based measures of the dimen-sions of knowledge flows, we identify sources of systematic measurement error associated with backward citations to both patent and nonpatent references. We find that patent citations reflect the codified knowledge flows from public research, but they appear to miss knowledge flows that are more private and contract-based in nature, as well as those used in firm basic research. We also find that firms’ patenting and citing strategies affect patent citations, making citations less indicative of knowledge flows. In addition, an illustrative analysis examining the magnitude and direction of measurement error bias suggests that measuring knowledge flows with patent citations can lead to substantial underestimation of the effect of public research on firms’ innova-tive performance. Throughout our analyses we find that nonpatent references (e.g., journals, con-ferences, etc.), not the more commonly used patent references, are a better measure of knowledge originating from public research.

Dynamics between patent latent variables and patent price

This paper focuses on studying the relationship between patent latent variables and patent price. From the existing literature, seven patent latent variables, namely age, generality, originality, foreign filings, technology field, forward citations, and backward citations were identified as having an influence on patent value. We used Ocean Tomo's patent auction price data in this study. We transformed the price and the predictor variables (excluding the dummy variables) to its logarithmic value. The OLS estimates revealed that forward citations and foreign filings were positively correlated to price. Both the variables jointly explained 14.79% of the variance in patent pricing. We did not find sufficient evidence to come up with any definite conclusions on the relationship between price and the variables such as age, technology field, generality, backward citations and originality. The Heckman two-stage sample selection model was used to test for selection bias.

The Patterns of Inter-Firm and Inter-Industry Knowledge Flows in the Netherlands

This paper presents a study of backward and forward patent citations in patents granted to firms and institutions in the Netherlands by the United States Patent and Trademark Office (USPTO). The study establishes different patterns of patent citation in recent Dutch patents belonging to different industrial classes. We run our model in the set of backward citations made in Dutch applicants’ patents during 1996-2006 and in the set of forward citations to patents issued to firms and organizations in the Netherlands during 1993-2006. We compare the patterns of knowledge utilization (represented by backward patent citations) and knowledge dissemination (represented by forward patent citations) and obtain evidence of inter- or intra-firm and inter- or intra-industry knowledge spillovers. In the context of effective competition and innovation policies we advocate for paying special attention to industry specifics when designing policy programs and measures directed at stimulating R&D cooperation and knowledge spillovers. We present evidence that policies for promoting better knowledge exchange among firms should also distinguish between the measures for promoting the inward and the outward knowledge flows for companies in the Netherlands.

Analysis of convergence in paper and printing industry

Fusion of new technologies and converge has led to the emergence of new industries. This paper uses patent data of the paper and electronics companies to evaluate their overlapping technologies in discovering new businesses based on technology convergence. Patent data was collected from the 87 main players operating in the RFID value chain. Backward citations and technology cycle time have been used to get an idea of knowledge spillovers and rate of technological innovation between the players. The recognised trends of the growing overlaps of the technological fields show indications for knowledge spillovers and convergence between industries. This type of patent analysis helps to recognise trajectory changes early in the industry and helps companies to take strategic decisions accordingly.

Trajectory patterns of technology fusion: Trend analysis and taxonomical grouping in nanobiotechnology

The potential of technology fusion has been advanced as a promising breakthrough function to create hybrid technologies. Despite its importance, however, the evolutionary path of technology fusion is yet unexplored. In this paper, by employing the case of nanobiotechnology, we attempt to deepen understanding of the development trajectories of technology fusion in three important aspects. The first aspect is the development of an index that measures the degree of fusion of cross-disciplinary technology at the meso level. The second aspect is to classify the trajectory patterns of technology fusion in terms of fusion degree. We analyze fusion mechanism by utilizing citation network analysis. The third aspect is to visualize the relationship between patents and their backward and forward patent citations, at the patent class level, with their direction on a citation map. This facilitates understanding of the overview as well as fusion patterns. The changes in fusion patterns are analyzed using time series comparisons. An empirical analysis in the nanobiotechnology field shows no positive relationship between the inflow and outflow degree of fusion. We also observe changes in the trajectory patterns of fusion over time. Analysis demonstrates that each fusion pattern has evolved in such a way that technologies focus more on their niche technologies, and that those technologies which cannot incorporate the technology fusion have been eliminated during the development process.

Determinants of patent withdrawals: Evidence from a sample of Italian applications with the EPO

This paper analyses the propensity to withdraw European patent applications within a regional sample of Italian applicants. The procedure for obtaining a granted patent from the EPO is composed of a series of sequential and selective steps imposing additional costs to the applicants. Accordingly, we argue that early withdrawals – i.e. those occurring before the proper examination process begins – should be treated separately from late withdrawals. Our findings show the probability of an early withdrawal is higher for applicants with lower resources and competencies and rises with the number of backward citations added by EPO examiners to the original application. Late withdrawals, instead, are negatively affected by one factor only: the size of patent family, which approximates the sunk costs born by applicants in order to extend the geographical scope of patent protection. Such a limited explanation suggests that the interventions of EPO examiners are likely to play a significant role in inducing late withdrawals.

Patents and the performance of technology firms: Evidence from initial public offerings in Germany

The objective of this study is to analyze the relationship between innovation and performance for German firms that went public at the “Neuer Markt” during the period from 1997 to 2002. In the empirical analysis we investigate in particular whether initial public offerings (IPOs) with more or higher quality patents outperformed IPOs with lower quality or no patented technology. For this we measure the impact of patents on underpricing and long-run performance and explain the magnitude of these valuation effects with the Fama–French value and growth factors, with patent-specific variables such as the number of IPC-classes, family size, the number of backward and forward citations, as well as with industry variables. The empirical evidence suggests that patents are a reliable indicator for the success and the short- and long-run performance of start-up technology firms that went public and that the valuation effects are more pronounced for higher quality patents.

PATENT CITATIONS INDICATING PRESENT VALUE OF THE BIOTECHNOLOGY BUSINESS

In this paper our aim is to assess the potential of using patent statistics in predicting the future sales anticipations and present value of a company active in the science-based industry. Instead of using conventional patent and patent application counts as indicators, we constructed patent citation weighted portfolios for each company. This way the heterogeneity of patents can be taken into account. Our data covers biotechnology patents held by Finnish biotechnology companies. Empirical results imply that particularly backward citations are related to present value estimations of the companies. In contrast to some previous studies, forward citations do not seem to predict the present value estimations. The findings provide some important implications on interpreting the significance of patent citations regarding valuation of science-based companies, and planning technology and innovation policies.

Ranking USPTO Patent Documents by Importance Using Random Surfer Method (PageRank)

This study attempted to construct an alternative method for ranking patents by their importance in order to improve the existing techniques of determining citation weighted patent stocks. We apply the random surfer PageRank method to the problem of ranking the importance of the patent documents issued to inventors by the United States Patent and Trademark Office. PageRank patent importance weights turn out to differ systematically from the weights based on the number of backward or forward citations. Yet PageRanks perform similarly to the knowledge transfer indicator, which is the ratio of forward to backward citations.

THE INSTITUTIONAL SOURCES OF KNOWLEDGE AND THE VALUE OF ACADEMIC PATENTS

This paper puts forward new potential determinants of patent value which are related to the identification of institutional sources of knowledge and the geographic scope of patenting strategy. The impact of these new indicators is evaluated through an empirical analysis that aims to explain the number of forward citations received by 208 patent families applied for by six Belgian universities. The new indicators provide a more in-depth understanding of the way non-patent citations, backward patent citations, co-assignees and the geographical scope for protection determine patent value. The policy implications induced by these results are the positive impact of collaboration between public research organisations and the need to focus on academic researchers with a high scientific profile in terms of publications in order to crystallize their tacit knowledge into high value academic patents. The views expressed in this article are purely those of the authors and may not in any circumstances be regarded as stating an official position of the EPO or of the ULB. All errors and omissions remain our sole responsibility.

US PATENT CITATIONS DATA AND INDUSTRIAL KNOWLEDGE SPILLOVERS

The aim of this paper is to empirically evaluate the US interindustry knowledge spillover using the NBER patents data file (1963–1999). Reputing the patent backward citations as a good proxy of the patent's knowledge spillover, we proceed by building a time series to each US manufacturing industry patent citations and their lags. Then, we generate the time series of the external and the internal knowledge flow indices, showing that traditional sectors are more technology-dependent from the others than the new one. Here, in the spirit of Pavitt [Pavitt, Research Policy 13, 343–73, 1984]. We derive a new taxonomy of innovation focusing on the ideas instead of the goods production in order to obtain the innovation linkage and trajectories. Once we determined that each sector's most cited patents are typically belong to the ‘new’ sectors, we evaluate the high- and low-tech sectors innovation effect on the whole economy innovation process. Confirming that the high-tech sectors, and its R&D expenditures, are the most important, we conclude that it is the giant's shoulders, substance of the whole economy.

Technological proximity and co-movements of stock returns

The objective of this study is to validate two measures of technological proximity constructed from patent statistics, namely, knowledge spillovers and research overlap, by examining their relationship with the co-movements of stock returns. A unique data set is compiled from the US patent statistics by tracing the links between patents as established by backward citations. The empirical findings from this study suggest that the two measures of technological proximity are positively related to the co-movements of stock returns.

Short communication

The systematic review explores personal experiences and perceptions of (and on) resident Indian women on family planning.We included qualitative studies conducted among women, husbands and mothers-in-law. Search on five databases (published between 2000 and May 8, 2019) and forward and backward citations search of included studies were undertaken (April 2020). Three-stage screening and data extraction were done independently. Iterative process was followed to thematically analyse the data and presented it using the World Health Organization conceptual framework on social determinants of health.Of 857 citations, we included 48 qualitative studies. Women's intent of using family planning services/methods was influenced by multiple factors such as socio-demographic characteristics. Women's agency and social status affected their standing in family planning decision-making. Fear of side-effects of contraception methods, access to information and support, and cultural and religious beliefs hindered the use of modern methods of contraceptive. Undesirable attitudes of service providers influenced underutilisation of family planning services. Ineffective contraceptive choice counselling, particularly for poor section of the community and high-risk groups were reported. While considering inter-pregnancy interval, some of the women opted for induced abortion to terminate unplanned pregnancy however, had meagre acceptance for using modern contraceptive methods.The findings call for reinvigorated efforts to provide effective and individually, religiously, regionally and culturally appropriate interventions to improve family planning access and ultimately support better health and rights of women in India.