The Grey Side of the Green Road : Empirical Assessment of Academic Publishing in the HAL Open Repository.

The paper provides empirical results on the part of grey literature in the French national open repository HAL. The results are based on a quantitative analysis of 973,968 deposits from 1,272 research laboratories affiliated the ten most important research universities in France (IDEX program). 35% of all deposits (documents and records) are grey literature. The main types of these items are conference papers (71%), PhD theses (11%) and preprints and working papers (8%). Their overall accessibility (degree of openness) is 37%, which is higher than commercial publications. Differences between document types, disciplines and institution are described. Further research is needed for a better understanding of how research laboratories are handling grey literature (licensing ...). A follow-up study in 2021 will provide this insight. [ABSTRACT FROM AUTHOR]