Author(s): Hall, Bronwyn H.; Jaffe, A; Trajtenberg, M | Abstract: We explore the usefulness of patent citations as a measure of the "importance" of a firm's patents, as indicated by the stock market valuation of the firm's intangible stock of knowledge. Using patents and citations for 1963-1995, we estimate Tobin's q equations on the ratios of RaD to assets stocks, patents to RaD, and citations to patents. We find that each ratio significantly affects market value, with an extra citation per patent boosting market value by 3%. Further findings indicate that "unpredictable" citations have a stronger effect than the predictable portion, and that self-citations are more valuable than external citations.

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Market value and patent citations

Empirical research on complementarity between organizational design decisions has traditionally focused on the question of existence of complementarity. In this paper, we take a broader approach to the issue, combining a productivity and an adoption approach, while including a search for contextual variables in the firms strategy that affects complementarity. Analysis of contextual variables is not only interesting per se, but also improves the productivity test for the existence of complementarity. We use our empirical methodology to analyze complementarity between innovation activities: internal research and development (R&D) and external knowledge acquisition. Our results suggest that internal R&D and external knowledge acquisition are complementary innovation activities, but that the degree of complementarity is sensitive to other elements of the firms strategic environment. We identify reliance on basic R&Dthe importance of universities and research centers as an information source for the innovation processas an important contextual variable affecting complementarity between internal and external innovation activities.

In Search of Complementarity in Innovation Strategy: Internal R&D and External Knowledge Acquisition

We investigate the hypothesis that the combination of three related innovations—1) information technology (IT), 2) complementary workplace reorganization, and 3) new products and services—constitute a significant skill-biased technical change affecting labor demand in the United States. Using detailed firm-level data, we find evidence of complementarities among all three of these innovations in factor demand and productivity regressions. In addition, firms that adopt these innovations tend to use more skilled labor. The effects of IT on labor demand are greater when IT is combined with the particular organizational investments we identify, highlighting the importance of IT-enabled organizational change.

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Information Technology, Workplace Organization, and the Demand for Skilled Labor: Firm-Level Evidence

Economics Of Discrimination

We analyze the relationship between inequality and economic growth from two directions. The first part of the survey examines the effect of inequality on growth, showing that when capital markets are imperfect, there is not necessarily a trade-off between equity and efficiency. It therefore provides an explanation for two recent empirical findings, namely, the negative impact of inequality and the positive effect of redistribution upon growth. The second part analyzes several mechanisms whereby growth may increase wage inequality, both across and within education cohorts. Technical change, and in particular the implementation of "General Purpose Technologies," stands as a crucial factor in explaining the recent upsurge in wage inequality.

Inequality and Economic Growth: The Perspective of the New Growth Theories

This paper studies the links between productivity, innovation and research at th level. We introduce three new features: (i) A structural model that explains pro by innovation output, and innovation output by research investment; (ii) New dat manufacturing firms, including the number of European patents and the percentage sales, as well as firm-level demand pull and technology push indicators; (iii) E which correct for selectivity and simultaneity biases and take into account the features of the available data: only a small proportion of firms engage in resea apply for patents; productivity, innovation and research are endogenously determ investment and capital are truncated variables, patents are count data and innov We find that using the more widespread methods, and the more usual data and mode may lead to sensibly different estimates. We find in particular that simultaneit with selectivity, and that both sources of biases must be taken into account tog results are consistent with many of the stylized facts of the empirical literatu of engaging in research (R&D) for a firm increases with its size (number of empl share and diversification, and with the demand pull and technology push indicato capital intensity) of a firm engaged in research increases with the same variabl research capital being strictly proportional to size). The firm innovation outpu patent numbers or innovative sales, rises with its research effort and with the indicators, either directly or indirectly through their effects on research. Fin correlates positively with an higher innovation output, even when controlling fo the skill composition of labor as well as for physical capital intensity.

Research, Innovation, and Productivity: An Econometric Analysis at the Firm Level

This paper studies the links between productivity, innovation and research at the firm level. We introduce three new features: (i) A structural model that explains productivity by innovation output, and innovation output by research investment: (ii) New data on French manufacturing firms, including the number of European patents and the percentage share of innovative sales, as well as firm-level demand pull and technology push indicators; (iii) Econometric methods which correct for selectivity and simultaneity biases and take into account the statistical features of the available data: only a small proportion of firms engage in research activities and/or apply for patents; productivity, innovation and research are endogenously determined; research investment and capital are truncated variables, patents are count data and innovative sales are interval data. We find that using the more widespread methods, and the more usual data and model specification, may lead to sensibly different estimates. We find in p...

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Patent citation data are used in a growing body of economics and business research on technological diffusion. Until now, there exists little evidence on whether patent citations are a good measure of knowledge flows. Our paper assesses the legitimacy of using European patent citations as a measure of technology flows. It uses information from the Community Innovation Survey collected by the French Service des Statistiques Industrielles (SESSI), which contain firms’ responses to questions about their innovative activity. We show that patent citations are indeed related to firms’ statements about their acquisition and dispersion of new technology, but that the strength and statistical significance of this relationship varies across geographical regions and across channels of knowledge diffusion.

How well do patent citations measure flows of technology? Evidence from French innovation surveys

Research, Innovation, and Productivity: an Econometric Analysis at the Firm Level

The purpose of this paper is to estimate the patent equation, an empirical counterpart to the ‘knowledge-production function’. Innovation output is measured through the number of European patent applications and the input by research capital, in a panel of French manufacturing firms. Estimating the innovation function raises specific issues related to count data. Using the framework of models with multiplicative errors, we explore and test for various specifications: correlated fixed effects, serial correlations, and weak exogeneity. We also present a first extension to lagged dependent variables. © 1997 John Wiley & Sons, Ltd.

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Emmanuel Duguet

Papers

Research, Innovation, and Productivity: An Econometric Analysis at the Firm Level

Research, Innovation, and Productivity: An Econometric Analysis at the Firm Level

How well do patent citations measure flows of technology? Evidence from French innovation surveys

Research, Innovation, and Productivity: an Econometric Analysis at the Firm Level

estimating the innovation function from patent numbers: gmm on count panel data ¤