How to interpret the position of private sector institutions in bibliometric rankings of research institutions

This paper analyzes the positions of institutions from the private domain in bibliometric rankings of as many as 27,000 research institutions and highlights factors that are crucial for a proper interpretation of such positions. It was found that among the institutions with the largest output in terms of published research articles, private firms are underrepresented, whereas in the top quartile of institutions with the largest citation impact firms are overrepresented. A firm's publication output is not a good indicator of its R&D investment: big firms in Pharmaceutics are both heavy investors in R&D and frequent publishers of scientific articles, whereas in Automobiles firms tend to invest heavily in R&D but their publication output is low. This is ascribed to the fact that the former need a validation of their results by the scientific community, while the latter do less so. Private institutions generating the largest citation impact tend to collaborate with the best public research institutions. This reflects the crucial importance of publicly funded research for the private sector.