Hunting scale-free properties in R&D collaboration networks: Self-organization, power-law and policy issues in the European aerospace research area

Based on previous studies of EU-subsidized research joint ventures, R&D collaboration networks, and aerospace industry, this work raises and tests a set of hypotheses in order to check whether the European aerospace research area shows a scale-free topology. Its main focus concerns the application of a proper power-law detecting methodology to most important parameters: projects' and organizations' direct and indirect centrality, organizations' membership, and finally projects' size and fund. While previous studies of other EU-subsidized research joint ventures carried on the analyses with relatively simpler methods and tested only the power-law form, our work employs minimum and significance values calculations, and contrasts the power-law with other heavy-tailed distributions, which are widely analysed and discussed. The results clearly state that some parameters can be substantially assimilated to a power-law, while others only moderately or not at all. An explanation of such differences is provided and grounded on the relation between self-organization and scale invariance, mostly confirming a direct dependence of the latter from the former. However, the peculiarities of projects' size distribution make the interpretation of that relationship more problematic and suggest the need to carefully investigate the effect produced in each specific context by external constraints. Further, the implications of the scale-free topological properties—and in particular of their occurrence in the relationship between organizations' direct and indirect connectivity—are explored and discussed also respect to the effectiveness of European research policies. Besides enhancing the understanding of EU-subsidized research joint ventures in the European aerospace research area, our work contributes to investigate the more general issues of the relationship between self-organization and power-law, and between organizations' direct and indirect connectivity within inter-organizational networks. Finally, the paper underlines the high relevance of scale-free properties—and thus, the need to follow a proper detection methodology—by showing their relationships with resilience and sustainability of socio-economic systems.