Acknowledgements
This study is conducted within the frame of the POERUP project, funded by the lifelong learning program of the European Commission (POERUP, 2013). The POERUP project aims to enable the development of policies to stimulate the uptake of open educational resources. Within the POERUP project, partners from the Open University of the Netherlands, Sero Consulting and the University of Leicester, and the University of Athabasca collaborated to gather all the data with help from the OEP initiatives under investigation.