Intra-EU vs. extra-EU scientific co-publication patterns in EU

The increase of co-authored papers is a recognized fact. At the same time the factors influencing this change is not well known. This article aims at studying the patterns of EU science co-authorships. We analyzed articles published in 18 EU countries and their intra-EU (within EU) and extra-EU (with partners outside EU) co-publication pattern in five scientific fields. The results point to a Europeanisation of shared co-authorship rather than an internationalization outside Europe. Smaller countries co-authored more with other EU countries than bigger countries while the co-authorship rate with extra-EU partners was not dependent of the country's size. The co-authorship patterns were also found to depend on the scientific field. Engineering and Computing & Technology was the field with the highest level of national publications and Physical, Chemical & Earth Sciences the field with the highest level of both intra-EU and extra-EU collaborations. These results support the view that a single market for research is developing within the EU with a seamless extension of national systems into other Member States ones.