The Ecology of Technological Progress: How Symbiosis and Competition Affect the Growth of Technology Domains

We show that the progress of technological knowledge is an inherently ecological process, wherein the growth rate of each technology domain depends on dynamics occurring in other technology domains. We identify two sources of ecological interdependence among technology domains. First, there are symbiotic interdependencies, implying that the rate of growth of one technology domain is driven by the advances made in other technology domains. Second, some technology domains compete with each other, implying that the rate at which a given technology domain advances varies inversely with the competitive pressure it receives from other technology domains. Based on all the technological knowledge patented in the United States between 1975 and 1999, we find statistical support for our argument and hypothese

The distribution of technological progress

The size distribution of the domains of US-patented technological knowledge obeys an exponential law, revealing a disproportionable concentration of progress among larger domains. Our analyses suggest that this phenomenon is explained by a combination of two factors. First, domains' trajectories of growth have inherently different potentials. Second, differences in domains' potentials are magnified by a mechanism—domains' self-hybridization—endogenous to the process of knowledge growth. Our results show that in addition to being stable, the observed distribution of technological progress is likely to arise under very general condition

Knowledge Specialization, Knowledge Brokerage and the Uneven Growth of Technology Domains

Why do certain domains of knowledge grow fast while others grow slowly or stagnate? Two distinct theoretical arguments hold that knowledge growth is enhanced by knowledge specialization and knowledge brokerage. Based on the notion of recombinant knowledge growth, we show that specialization and brokerage are opposing modes of knowledge generation, the difference between them lying in the extent to which homogeneous vs. heterogeneous input ideas get creatively recombined. Accordingly, we investigate how both modes of knowledge generation can enhance the growth of technology domains. To address this question, we develop an argument that reconciles both specialization and brokerage into a dynamic explanation. Our contention is that specializing in an increasingly homogeneous set of input ideas is both more efficient and less risky than brokering knowledge. Nevertheless, specializing implies progressively exhausting available recombinant possibilities, while brokerage creates new ones. Hence, technology domains tend to grow faster when they specialize, but the more specialized they become, the more they need knowledge brokerage to grow. We cast out our argument into five hypotheses that predict how growth rates vary across technology domain

Indicazioni all\u2019uso delle protesi vascolari per l\u2019accesso emodialitico : un\u2019esperienza italiana basata sul consenso

In Italy, the use of arteriovenous grafts (AVGs) is limited (1-4%) due to different approaches to vascular access management compared to other countries, where guidelines that may not apply to the Italian setting have been produced. Therefore, the Vascular Access Study Group of the Italian Society of Nephrology produced this position paper, providing a list of 8 recommendations built upon current guidelines. The most controversial and innovative issues of the existing guidelines have been summed up in 12 different topics. We selected 60 Italian dialysis graft experts, nephrologists and vascular surgeons (PP1SIN Study Investigators). They were asked to express their approval or disapproval on each issue, thus creating a new method to share and exchange information. Almost all agreed on specific criteria for the choice of AVG over native arteriovenous fistulas (AVF) and tunneled venous catheters (tVC) and on the necessary conditions to implant them. They did not fully agree on the use of AVG in obese patients and patients at risk of developing ischemia, as an alternative to brachiobasilic fistula with vein transposition, and in case of a poorly organized setting. When AVF is feasible, it should be preferred. AVGs are indicated when superficial veins are unavailable or to repair an AVF (bridge graft). An AVG is an alternative to tVC if the expected patient survival is long enough to allow clinical benefits. The ultimate choice of the graft type is made by the physician in charge of the surgical intervention. Antithrombotic prophylaxis may be justified in some cases

On the Growth of Scientific Knowledge: Yeast Biology as a Case Study

The tempo and mode of human knowledge expansion is an enduring yet poorly understood topic. Through a temporal network analysis of three decades of discoveries of protein interactions and genetic interactions in baker's yeast, we show that the growth of scientific knowledge is exponential over time and that important subjects tend to be studied earlier. However, expansions of different domains of knowledge are highly heterogeneous and episodic such that the temporal turnover of knowledge hubs is much greater than expected by chance. Familiar subjects are preferentially studied over new subjects, leading to a reduced pace of innovation. While research is increasingly done in teams, the number of discoveries per researcher is greater in smaller teams. These findings reveal collective human behaviors in scientific research and help design better strategies in future knowledge exploration

A note on structural holes theory and niche overlap

Diffuse competition due to niche overlap between actors without (direct) ties with each other, constrains their structural autonomy. This is not dealt with in Burt’s mathematical model of his well-known structural holes theory. We fix his model by introducing a network measure of niche overlap

The evolving structure of the technological landscape

In this paper, we set out to analyse the evolving structure of the technological landscape on which our knowledge-based economies thrive. To this end, we develop a network-analytic model, which we use to characterise and study the evolving pattern of citations among all patents granted in the USA from 1975 to 1999. We find that (i) the structure of knowledge spillovers among technology domains features the distinguishing properties of a small world topology. However, (ii) during the 25 years observed there has been a consistent trend away from the small world topology, which (iii) is entirely explained by the disappearance of specialties encompassing multiple tightly interconnected technology domains. Our findings bear important strategic implications for both managers and policy maker