Testing the science/technology relationship by analysis of patent citations of scientific papers after decomposition of both science and technology

The relationship of scientific knowledge development to technological development is widely recognized as one of the most important and complex aspects of technological evolution. This paper adds to our understanding of the relationship through use of a more rigorous structure for differentiating among technologies based upon technological domains (defined as consisting of the artifacts over time that fulfill a specific generic function using a specific body of technical knowledge). The key findings of the work are: Firstly, a Pearson correlation of 0.564 is found between technological relatedness among technological domains based upon patents citing other patents and technological relatedness among technological domains based upon patents citing similar scientific papers (assessed through 176 scientific categories developed by ISI). This result indicates that a large portion (but not all) of technological relatedness is due to relatedness of the underlying scientific categories. Secondly, the overall structure of the links found between scientific categories and technological domains is many-to-many rather than focused indicating a sciencefostered mechanism for fairly broad “spillover”: Specific technological domains cite a wide variety of scientific categories (in 2010 the average number of scientific categories cited by the 44 individual technological domains studied was 36); Some scientific categories are cited in a variety of domains (124 scientific categories are cited in 30% or more of the 44 domains over the period studied, 19762013). Thirdly, Some evidence is found supporting the co-evolution of science and technology but the evidence is not strong: Growth in the number of patents in a technological domain and growth in the number of scientific papers in the scientific super-discipline that is the most highly cited by patents in the domain are strongly correlated for some domains but not for others; When the growth of patents in a domain is exponential with time, the exponent for growth of papers in the most highly cited scientific categories has a Pearson correlation coefficient of 0.617 with the exponent for patent growth showing strong but not complete correlation particularly considering the domains where patent growth is non-exponential. Prior research that identifies emerging patent clusters and independent prior research identifying emerging scientific topics show statistically significant but qualitatively weak inter-relationships between the clusters and topics. This work also offers evidence that patent cluster emergence can, but does not usually, precede the emergence of related scientific topics. The lack of clear evidence for co-evolution is interpreted as resulting from the documented complex many-to-many relationship of science categories and technological domains and is not considered evidence against co-evolution.