Abstract
This study aims to examine the differential effect of technological diversification on research and development (R&D) productivity based on the qualitative properties of technology portfolios (i.e., the direction of technological diversification). Using the U.S. patent database from 1980 to 2010, we divided overall technological diversification into related and unrelated technological diversification; furthermore, the two potential moderating factors of technology portfolio centrality and R&D consistency were tested across the different types of technological diversification. The notable findings are as follows: First, technology portfolio centrality has a positive moderating effect that is more pronounced as the degree of technological diversification increases. Second, R&D consistency has a positive and linear moderating effect. Third, the positive (negative) effect of technological diversification is more pronounced under related (unrelated) technological diversification. Consequently, firms can better utilize the R&D-productivity-enhancing effect of technological diversification by considering both the current degree of technological diversification and the properties of their technology portfolios.
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Data availability
The datasets generated and analyzed during the current study are available in ‘https://wrds-web.wharton.upenn.edu/’.
Code availability
Available upon request.
Notes
Focusing on firm-specific innovative conditions, Choi and Lee (2021) found a U-shaped relationship between technological diversification and R&D productivity with positive moderating effects of firm-specific core-technology competence and pool of knowledge spillovers.
Technological relatedness (or coherence) refers to the degree to which technologies constituting a technology portfolio are technologically related, sharing a similar technological knowledge base and common scientific principles (Breschi et al., 2003; Kim et al., 2016; Leten et al., 2007; Nesta & Saviotti, 2005).
The criteria are based on the indicators for the technological importance (quality) of patents; this includes the degree of the technological impact and diffusion into other technological fields (Squicciarini et al., 2013), and the additional adjustment required for reflecting the fast-changing technological environment. This study employs the patent class-level citation network and centrality (i.e., PageRank), which are widely used in social network analysis, to measure the proxy variable. See Sects. 2.2 and 4.2 for further details.
Dindaroğlu (2018) found that technological diversification and R&D productivity have an S-shaped cubic relationship, however, the coefficients of the polynomial terms are consistent with that of a nearly U-shaped relationship.
Among various measurements for the centrality index, we employed Google’s PageRank centrality. The detailed description and the deriving procedures are provided in Sect. 4.2.
The robustness check for this conjecture proceeds in Sect. 5.2.
According to Klevorick et al. (1995), technological advances occurring within a specific technological field and from technologically applicable external fields expand the pool of technological opportunities, offsetting diminishing returns to R&D.
Dechezleprêtre et al. (2014) used a centrality index from a patent-level citation network as a proxy variable of the intensity of knowledge spillovers among patents.
The hypothesis is likely to be valid at least in the short run. However, in the long run, consistent R&D efforts in previously active technological fields may deplete technological opportunities (Klevorick et al., 1995) and diminish marginal returns to R&D, as ideas are getting hard to find (Bloom et al., 2020). The long-run effect is not explored as this study mainly focuses on a short-run base (e.g., after two years).
Using the property of entropy method, technological diversification can be divided into two parts of related and unrelated technological diversification, based on technological relatedness. See Sect. 4.3 for the detailed derivation process. For simplicity, we use technological relatedness as a term indicating the proportion of related technological diversification out of overall technological diversification.
Both technological relatedness and R&D consistency are related to innovation strategies managing the balance between technological exploration and exploitation. While R&D consistency reflects the dynamic nature of technological consistency between the current technology portfolio and the accumulated technological knowledge base, technological relatedness concentrates on the technological coherence among technologies constituting the current technology portfolio (i.e., static nature).
The observation year is restricted to 2010 owing to the truncation issue of forward citations that citations for recent patents after the end of the sample are not considered, thereby distorted downwardly (Hall et al., 2001).
Degree centrality and closeness centrality measures cannot capture the indirect interactions among actors in a network.
It considers not the total number of citations but the relative ratio, normalizing the absolute size of patent citations caused by the technology-specific citation trend.
Chen et al. (2007) provided the conjecture and empirical evidence for the usage of the value 0.5 in the citation network. First, entries in the citation list, on average, are collected within two searches following the citation links. Second, the portion of the followed citation (e.g., B in an A to B, A to C, and B to C citation loop) is approximately 50%, implying the probability of following this indirect citation path (i.e., \(1-d\)) is close to 0.5, assuming that A followed the citation path of B.
The value is set to one if there is no forward citation and added one for each additional forward citation.
The derivation of the decomposition process is described in Palepu (1985).
Refer to Sect. 4.2 for the detailed derivation process and notational information of the PageRank centrality (\(TECHCE{N}_{jt}\)).
The usage of a fixed-effect model rather than a random-effect model is justified following the Hausman test.
The sample is constructed with 19,778 observations out of the total 69,051 observations. While the mean R&D expenditures (total sales) of innovative firms in the total sample is 75.98 (1,987.76), the mean value in the matched sample is 191.16 (4,405.00).
The upper bound for the positive effect of technological diversification (8.15) exceeds the largest sample level (4.65). Figure 4 illustrates the result.
The negative moderating effect is related to Hypotheses 2 and 3 that firms at an early stage of exploratory technological diversification are more likely to suffer from technological competence-destroying effects. Hence, unless R&D consistency is sufficiently large to offset the negative moderating effect, firms at an early stage of technological diversification cannot effectively manage the positive moderating effects of technology portfolio centrality and are more likely to be dominated by harmful effects, such as R&D competition from the active R&D activities around technological fields with a high centrality index. The moderating effect of technology portfolio centrality in Model (6) of Table 2 is as follows: \(\frac{\partial lnRDPROD}{\partial TD\partial lnPORTCEN}=-0.182+0.224TD\).
The positive moderating effect of R&D consistency on related technological diversification vanishes in Models (4) and (5) of Table 3. The results are explained as follows: First, the high correlation between two variables in that both are associated with exploitative R&D activities can boost the standard errors. Second, whereas R&D consistency attenuates harmful effects of technological diversification on R&D productivity, related technological diversification generates no significant harmful effects.
The variable of technological relatedness (\(TECHREL\)), distributed over values between 0 and 1, is constructed as follows: \(TECHREL=\frac{TD\_R}{TD}\). It is not defined when the degree of overall technological diversification equals zero. The value of technological relatedness is set to one for those firms with zero degrees of technological diversification, given that concentrating on a single technological field implies the common usage of technological knowledge base across the R&D projects.
All of the alternative variables are normalized by dividing them with mean values for each cohort (i.e., by patent class and year) in consideration of the class- and time-specific trend of patent applications and citation activities (Hall et al., 2001).
For instance, R&D consistency of firm \(i\) at the observation year \(t\) with the 3-year moving average patent counts \((RDCON{S}_{it}^{3YMA})\) is measured by using a vector of the current technology portfolio where each column contains a 3-year average of the number of patents (i.e., the average value of \({P}_{ijt}\), \({P}_{ijt-1}\), and \({P}_{ijt-2}\)) and a vector of the knowledge stock where each column contains the accumulated stock of technological knowledge until the observation year \(t-3\).
References
Abernathy, W. J., & Clark, K. B. (1985). Innovation: Mapping the winds of creative destruction. Research Policy, 14, 3–22.
Ahuja, G., & Katila, R. (2001). Technological acquisitions and the innovation performance of acquiring firms: A longitudinal study. Strategic Management Journal, 22, 197–220.
Ahuja, G., & Lampert, C. M. (2001). Entrepreneurship in the large corporation: A longitudinal study of how established firms create breakthrough inventions. Strategic Management Journal, 22, 521–543.
Alcacer, J., & Gittelman, M. (2006). Patent citations as a measure of knowledge flows: The influence of examiner citations. Review of Economics and Statistics, 88, 774–779.
Archibugi, D., & Planta, M. (1996). Measuring technological change through patents and innovation surveys. Technovation, 16, 451–519.
Argyres, N. (1996). Capabilities, technological diversification and divisionalization. Strategic Management Journal, 39(537–548), 395.
Basberg, B. L. (1987). Patents and the measurement of technological change: A survey of the literature. Research Policy, 16, 131–141.
Berkhin, P. (2005). A survey on PageRank computing. Internet Mathematics, 2, 73–120.
Besanko, D., Dranove, D., Shanley, M., & Schaefer, S. (2012). Economics of strategy. Wiley.
Bloom, N., Jones, C. I., Reenen, J. V., & Webb, M. (2020). Are ideas getting harder to find? American Economic Review, 110, 1104–1144.
Breschi, S., Lissoni, F., & Malerba, F. (2003). Knowledge-relatedness in firm technological diversification. Research Policy, 32, 69–87.
Brin, S., & Page, L. (1998). The anatomy of a large-scale hypertextual web search engine. Computer Networks and ISDN Systems, 30, 107–117.
Bruck, P., Réthy, I., Szente, J., Tobochnik, J., & Érdi, P. (2016). Recognition of emerging technology trends: Class-selective study of citations in the US patent citation network. Scientometrics, 107, 1465–1475.
Ceipek, R., Hautz, J., Mayer, M. C., & Matzler, K. (2019). Technological diversification: A systematic review of antecedents, outcomes and moderating effects. International Journal of Management Reviews, 21, 466–497.
Chen, D.-Z., Chang, H.-W., Huang, M.-H., & Fu, F.-C. (2005). Core technologies and key industries in Taiwan from 1978 to 2002: A perspective from patent analysis. Scientometrics, 64, 31–53.
Chen, P., Xie, H., Maslov, S., & Redner, S. (2007). Finding scientific gems with Google’s PageRank algorithm. Journal of Informetrics, 1, 8–15.
Choi, M., & Lee, C.-Y. (2021). Technological diversification and R&D productivity: the moderating effects of knowledge spillovers and core-technology competence. Technovation, 104, 102249.
Cohen, W. M., & Klepper, S. (1996). A reprise of size and R&D. Economic Journal, 106, 925–951.
Cohen, W. M., & Levinthal, D. A. (1989). Innovation and learning: Two faces of R&D. Economic Journal, 99, 569–596.
Cohen, W. M., & Levinthal, D. A. (1990). Absorptive capacity: A new perspective on learning and innovation. Administrative Science Quarterly, 35, 128–152.
Dechezleprêtre, A., Martin, R., & Mohnen, M. (2014). Knowledge spillovers from clean and dirty technologies. CEP Discussion Paper No. 1300. Centre for Economic Performance, LSE.
Dindaroğlu, B. (2018). Determinants of patent quality in U.S. manufacturing: Technological diversity, appropriability, and firm size. Journal of Technological Transfer, 43, 1083–1106.
Duguet, E., & MacGarvie, M. (2005). How well do patent citations measure flows of technology? Evidence from French innovation surveys. Economics of Innovation and New Technology, 14, 375–393.
Eggers, J. P., & Kaul, A. (2018). Motivation and ability? a behavioral perspective on the pursuit of radical invention in multi-technology incumbents. Academy of Management Journal, 61, 67–93.
Fleming, L., & Sorenson, O. (2001). Technology as a complex adaptive system: Evidence from patent data. Research Policy, 30, 1019–1039.
Gangulli, P. (2004). Patents and patent information in 1979 and 2004: A perspective from India. World Patent Information, 26, 61–62.
Garcia-Vega, M. (2006). Does technological diversification promote innovation? An empirical analysis for European firms. Research Policy, 35, 230–246.
Gavetti, G., Levinthal, D. A., & Rivkin, J. W. (2005). Strategy making in novel and complex worlds: The power of analogy. Strategic Management Journal, 26, 691–712.
Granstrand, O. (1998). Toward a theory of the technology-based firm. Research Policy, 27, 465–489.
Granstrand, O., & Oskarsson, C. (1994). Technology diversification in “mul-tech” corporations. IEEE Transactions on Engineering Management, 41, 355–364.
Griffith, R., Redding, S., & Reenen, J. V. (2004). Mapping the two faces of R&D: Productivity growth in a panel of OECD industries. Review of Economics and Statistics, 86, 883–895.
Griliches, Z. (1979). Issues in assessing the contribution of research and development to productivity growth. Bell Journal of Economics, 10, 92–116.
Grupp, H., Lacasa, D., & Schmoch, U. (2003). Tracing technological change over long periods in Germany in chemicals using patent statistics. Scientometrics, 57, 175–195.
Hall, B. H., Jaffe, A. B., & Trajtenberg, M. (2001). The NBER patent citations data file: lessons, insights and methodological tools. NBER Working Paper No. 8498. National Bureau of Economic Research.
Hall, B. H., Jaffe, A. B., & Trajtenberg, M. (2005). Market value and patent citations. RAND Journal of Economics, 36, 16–38.
Ham, R. M., Linden, G., & Appleyard, M. M. (1998). The evolving role of semiconductor consortia in the United States and Japan. California Management Review, 41, 137–163.
Han, Y. J., & Park, Y. (2006). Patent network analysis of inter-industrial knowledge flows: The case of Korea between traditional and emerging industries. World Patent Information, 28, 235–247.
Harhoff, D., Scherer, F. M., & Vopel, K. (2003). Citations, family size, opposition and the value of patent rights. Research Policy, 32, 1343–1363.
Heckman, J. J. (1979). Sample selection bias as a specification error. Econometrica, 47, 153–161.
Henderson, R., & Cockburn, I. (1996). Scale, scope, and spillovers: The determinants of research productivity in drug discovery. RAND Journal of Economics, 27, 32–59.
Hohberger, J., Almeida, P., & Parada, P. (2015). The direction of firm innovation: The contrasting roles of strategic alliances and individual scientific collaborations. Research Policy, 44, 1473–1487.
Hu, A. G., & Jaffe, A. B. (2003). Patent citations and international knowledge flow: The cases of Korea and Taiwan. International Journal of Industrial Organization, 21, 849–880.
Huang, Y. F., & Chen, C. J. (2010). The impact of technological diversity and organizational slack on innovation. Technovation, 30, 420–428.
Jaffe, A. B. (1986). Technological opportunity and spillovers of R&D: Evidence from firms’ patents, profits, and market value. American Economic Review, 76, 984–1001.
Jaffe, A. B. (1989). Characterizing the “technological position” of firms, with application to quantifying technological opportunity and research spillovers. Research Policy, 18, 87–97.
Jaffe, A. B., & Trajtenberg, M. (1999). International knowledge flows: Evidence from patent citations. Economics of Innovation and New Technology, 8, 105–136.
Jaffe, A. B., & Trajtenberg, M. (2002). Patents, citations, and innovations: A window on the knowledge economy. MIT Press.
Kim, J., Lee, C.-Y., & Cho, Y. (2016). Technological diversification, core-technology competence, and firm growth. Research Policy, 45, 113–124.
Klepper, S., & Simons, K. L. (2000). Dominance by birthright: Entry or prior radio producers and competitive ramifications in the U.S. television receiver industry. Strategic Management Journal, 21, 997–1016.
Klette, T. J. (1996). R&D, scope economies, and plant performance. RAND Journal of Economics, 27, 502–522.
Klette, T. J., & Kortum, S. (2004). Innovating firms and aggregate innovation. Journal of Political Economy, 112, 986–1018.
Klevorick, A. K., Levin, R. C., Nelson, R. R., & Winter, S. G. (1995). On the sources and significance of interindustry differences in technological opportunities. Research Policy, 24, 185–205.
Kodama, F. (1992). Technology fusion and the new R&D. Harvard Business Review, 70, 70–78.
Kogan, L., Papanikolaou, D., Seru, A., & Stoffman, N. (2017). Technological innovation, resource allocation, and growth. Quarterly Journal of Economics, 132, 665–712.
Kogut, B., & Zander, U. (1992). Knowledge of the firm, combinative capabilities, and the replication of technology. Organization Science, 3, 383–397.
Lanjouw, J. O., & Schankerman, M. (2004). Patent quality and research productivity: Measuring innovation with multiple indicators. Economic Journal, 114, 441–465.
Lee, H., Kim, C., Cho, H., & Park, Y. (2009). An ANP-based technology network for identification of core technologies: A case of telecommunication technologies. Expert Systems with Applications, 36, 894–908.
Leten, B., Belderbos, R., & Looy, B. V. (2007). Technological diversification, coherence, and performance of firms. Journal of Product Innovation Management, 24, 567–579.
Li, S., Zhang, X., Xu, H., Fang, S., Garces, E., & Daim, T. (2020). Measuring strategic technological strength: patent portfolio model. Technological Forecasting and Social Change, 157, Article 120119.
Lin, B., & Chen, J. (2005). Corporate technology portfolios and R&D performance measure: A study of technology intensive firms. R&D Management, 35, 157–170.
Lukach, R., & Lukach, M. (2007). Ranking USPTO patent documents by importance using random surfer method (pagerank). Available at SSRN: https://doi.org/10.2139/ssrn.996595
March, J. G. (1991). Exploration and exploitation in organizational learning. Organization Science, 2, 71–87.
Mariani, M. S., Medo, M., & Lafond, F. (2019). Early identification of important patents: Design and validation of citation network metrics. Technological Forecasting and Social Change, 146, 644–654.
Mariani, M. S., Medo, M., & Zhang, Y. C. (2016). Identification of milestone papers through time-balanced network centrality. Journal of Informetrics, 10, 1207–1223.
Markowitz, H. (1952). Portfolio selection. Journal of Finance, 7, 77–91.
Matusik, S. F., & Fitza, M. A. (2012). Diversification in the venture capital industry: Leveraging knowledge under uncertainty. Strategic Management Journal, 33, 407–426.
Miller, D. J. (2006). Technological diversity, related diversification, and firm performance. Strategic Management Journal, 27, 601–619.
Narin, F., Noma, E., & Perry, R. (1987). Patents as indicators of corporate technological strength. Research Policy, 16, 143–155.
Narula, R. (2004). R&D collaboration by SMEs: New opportunities and limitations in the face of globalisation. Technovation, 24, 153–161.
Nesta, L., & Saviotti, P. P. (2005). Coherence of the knowledge base and the firm’s innovative performance: Evidence from the US pharmaceutical industry. Journal of Industrial Economics, 53, 123–142.
Palepu, K. (1985). Diversification strategy, profit performance and the entropy measure. Strategic Management Journal, 6, 239–255.
Pavitt, K. (1982). R&D, patenting and innovative activities: A statistical exploration. Research Policy, 11, 33–51.
Penrose, E. (1959). The theory of the growth of the firm. Oxford University Press.
Piscitello, L. (2000). Relatedness and coherence in technological and product diversification of the world’s largest firms. Structural Change and Economic Dynamics, 11, 295–315.
Piscitello, L. (2004). Corporate diversification, coherence and economic performance. Industrial and Corporate Change, 13, 757–787.
Quintana-Garcia, C., & Benavides-Velasco, C. (2008). Innovative competence, exploration and exploitation: The influence of technological diversification. Research Policy, 37, 492–507.
Romer, P. M. (1990). Endogenous technological change. Journal of Political Economy, 98, 71–102.
Rosenkopf, L., & Nerkar, A. (2001). Beyond local search: Boundary-spanning, exploration, and impact in the optical disk industry. Strategic Management Journal, 22, 287–306.
Seru, A. (2014). Firm boundaries matter: Evidence from conglomerates and R&D activity. Journal of Financial Economics, 111, 381–405.
Singh, A., Triulzi, G., & Magee, C. L. (2021). Technological improvement rate predictions for all technologies: use of patent data and an extended domain description. Research Policy, 50, Article 104294.
Squicciarini, M., Dernis, H., & Criscuolo, C. (2013). Measuring patent quality: Indicators of technological and economic value. OECD Science, Technology and Industry Working Papers, No. 2013/03, OECD Publishing.
Suzuki, J., & Kodama, F. (2004). Technological diversity of persistent innovators in Japan: Two case studies of large Japanese firms. Research Policy, 33, 531–549.
Teece, D. J., Pisano, G., & Shuen, A. (1997). Dynamic capabilities and strategic management. Strategic Management Journal, 18, 509–533.
Trajtenberg, M. (1990). A penny for your quotes: Patent citations and the value of innovations. RAND Journal of Economics, 21, 172–187.
Triulzi, G., Alstott, J., & Magee, C. L. (2020). Estimating technology performance improvement rates by mining patent data. Technological Forecasting and Social Change, 158, Article 120100.
Tushman, M. L., & Anderson, P. (1986). Technological discontinuities and organizational environments. Administrative Science Quarterly, 31, 439–465.
Ullah, S., Akhtar, P., & Zaefarian, G. (2018). Dealing with endogeneity bias: The generalized method of moments (GMM) for panel data. Industrial Marketing Management, 71, 69–78.
Valvano, S., & Vannoni, D. (2003). Diversification strategies and corporate coherence evidence from Italian leading firms. Review of Industrial Organization, 23, 25–41.
Walker, D., Xie, H., Yan, K. K., & Maslov, S. (2007). Ranking scientific publications using a model of network traffic. Journal of Statistical Mechanics: Theory and Experiment, 2007, 6–10.
Wintoki, M. B., Linck, J. S., & Netter, J. M. (2012). Endogeneity and the dynamics of internal corporate governance. Journal of Financial Economics, 105, 581–606.
Yoon, B., & Park, Y. (2004). A text-mining-based patent network: Analytical tool for high-technology trend. Journal of High Technology Management Research, 15, 37–50.
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Yoo, SH., Lee, CY. Technological diversification, technology portfolio properties, and R&D productivity. J Technol Transf 48, 2074–2105 (2023). https://doi.org/10.1007/s10961-022-09953-x
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DOI: https://doi.org/10.1007/s10961-022-09953-x