• Is the United States losing ground in science? A global perspective on the world science system in 2005

      Leydesdorff, Loet; Wagner, Caroline S. (2006-11)
      Based on the Science Citation Index - Expanded web-version, the USA is still by far the strongest nation in terms of scientific performance. Its relative decline in percentage share of publications is largely due to the emergence of China and other Asian nations. In terms of citations, the competitive advantage of the American "domestic market" is diminished, while the European Union (EU) is profiting more from the enlargement of the database over time than the US. However, the USA is still outperforming all other countries in terms of highly cited papers and citation/publication ratios, and it is more successful than the EU in coordinating its research efforts in strategic priority areas like nanotechnology. In this field, the People's Republic of China (PRC) has become second largest in 2005 in both numbers of papers published and citations behind the USA.
    • Network Structure, Self-Organization and the Growth of International Collaboration in Science. Research Policy, 34(10), 2005, 1608-1618.

      Wagner, Caroline S.; Leydesdorff, Loet (2005)
      Using data from co-authorships at the international level in all fields of science in 1990 and 2000, and within six case studies at the sub-field level in 2000, different explanations for the growth of international collaboration in science and technology are explored. We find that few of the explanations within the literature can be supported by a detailed review of the growth of international collaboration during the 1990s. We hypothesize that growth may be due to recognition and rewards as ordering mechanisms within the system. We apply new tools emerging from network science to test whether international collaborations can organize based on rules of recognition and reward. These enquiries show that the growth of international co-authorships can be attributed to self-organizing phenomenon based on preferential attachment among collaborators at the sub-field level. The co-authorship links can be considered as a complex network with sub-dynamics involving features of both competition and cooperation. The analysis suggests that the growth of international collaboration during the 1990s has more likely emerged from dynamics at the sub-field level operating in all fields of science, albeit under institutional constraints. Implications for the management of global scientific collaborations are explored.