Over the past 20 years, numerous EU collaboration networks across the continent have taken research, development and knowledge sharing to an admirably high level. These networks have become almost as important as the scientific and technological results they produce. The EU Framework Programmes (FPs) have been pivotal for transforming informal nation-based networks of research among academia and industry into formal collaboration arrangements between organisations at European level. In this light, it is crucial to analyse these networks and their link to FPs, enabling the EU to design even better networks and frameworks in the future. Do collaborative organisational links increase over time? Is it possible to identify optimal network structures by areas of research and funding instruments? Who are the key players in the FPs? A network analysis of the FPs is an important analytical tool for the overall evaluation of results and impact of research and development (R&D) policies in the EU. It helps answer these questions and many more. The EU-funded study 'Centrality analysis in research networks' (CAIRN) has investigated these issues and thoroughly analysed the nature of networks under the different FPs. Its main objective was to advance understanding of transnational research networks and identify the role played by the most central organisations in these networks. Overall, it found that FP success comes from integrating research teams from new Member States and small communities into wider networks, a setup that strengthens the European Research Area (ERA). CAIRN outlined the type of networks involved and related industry clusters, analysing types of members (e.g. universities and companies), levels of collaboration and ability to expand. It found, among many important conclusions, that different kinds of networks represent different answers to the priorities of the ERA. These priorities include enhancing collaboration, advancing research, building expertise and disseminating knowledge. Universities were seen as crucial in furthering excellence and contributing to cohesion of the ERA. Integrated Projects and Networks of Excellence also strengthened the ERA by enhancing collaboration. They facilitated research agendas and integrated smaller research communities and new Member States. They also encouraged larger projects with more participants. In addition, CAIRN discovered that the ERA could promote a stronger European market for research by enhancing research organisations and fostering knowledge sharing. Importantly, CAIRN also found that the energy and environment themes have promoted integration of new organisations. This reflects strong production and dissemination of knowledge that benefits the public good, highlighting the need for even more inclusive networks. Monitoring the move towards the ERA is seen as crucial for the welfare of Europe. Beyond the analysis of publications and patents, projects like CAIRN have an important role in assessing FP effectiveness.