Emerson G. Escolar, Yasuaki Hiraoka, Mitsuru Igami, Yasin Ozcan
arXiv 31 Aug 2019 · Econometrics · publishedResearch Policy (2020) · 4 citations (OpenAlex)
arXiv:1909.00257 · PDF · DOI · OpenAlex · Extracted main text
Where do firms innovate? Mapping their locations and directions in technological space is challenging due to its high dimensionality. We propose a new method to characterize firms' inventive activities via topological data analysis (TDA) that represents high-dimensional data in a shape graph. Applying this method to 333 major firms' patents in 1976--2005 reveals substantial heterogeneity: some firms remain undifferentiated; others develop unique portfolios. Firms with unique trajectories, which we define and measure graph-theoretically as "flares" in the Mapper graph, perform better. This association is statistically and economically significant, and continues to hold after we control for portfolio size, firm survivorship, industry classification, and firm fixed effects. By contrast, existing techniques -- such as principal component analysis (PCA) and Jaffe's (1989) clustering method -- struggle to track these firm-level dynamics.
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The works this paper leans on most, across its whole bibliography — not restricted to papers in our corpus. Ranked by composite intensity, which combines how often a work is mentioned, how many sections mention it, and how much of that falls in the main text rather than the appendix.
| Reference | Intensity | Mentions | Sections | Main text | |
|---|---|---|---|---|---|
| 1 | Jaffe, Adam (1989) Characterizing the “technological position” of firms, with application to quantifying technological opportunity and research spi… | 0.737 | 3 | 2 | 100% |
| 2 | Singh, Gurjeet, Mémoli, Facundo, Carlsson, Gunnar (2007) Topological methods for the analysis of high dimensional data sets and 3d object recognition. | 0.511 | 2 | 2 | 50% |
| 3 | Azoulay, Pierre, Fons-Rosen, Christian, Graff Zivin, Joshua S (2019) Does Science Advance One Funeral at a Time? | 0.405 | 1 | 1 | 100% |
| 4 | Berry, Steven, Levinsohn, James, Pakes, Ariel (1995) Automobile prices in market equilibrium | 0.405 | 1 | 1 | 100% |
| 5 | Bar, Talia, Leiponen, Aija (2012) A measure of technological distance | 0.405 | 1 | 1 | 100% |
| 6 | Benner, Mary, Waldfogel, Joel (2008) Close to you? Bias and precision in patent-based measures of technological proximity | 0.405 | 1 | 1 | 100% |
| 7 | Bloom, Nicholas, Schankerman, Mark, Van Reenen, John (2013) Identifying Technology Spillovers and Product Market Rivalry | 0.405 | 1 | 1 | 100% |
| 8 | Cohen, Wesley M., Hall, Bronwyn H., Rosenberg, Nathan (2010) Fifty Years of Empirical Studies of Innovative Activity and Performance | 0.405 | 1 | 1 | 100% |
| 9 | Ericson, Richard, Pakes, Ariel (1995) Markov-perfect industry dynamics: A framework for empirical work | 0.405 | 1 | 1 | 100% |
| 10 | Jaffe, Adam (1986) Technological Opportunity and Spillovers of R&D: Evidence from Firms' Patents, Profits, and Market Value | 0.405 | 1 | 1 | 100% |
Showing the top 10 of 35 scored citations.