The OA monitor uses the information on publications provided by Unpaywall to calculate the OA proportions and to assign an OA model to each publication. For this purpose, the following checks are run in sequence:
|Gold and no APCs (based on DOAJ)||Diamond|
|Journal_is_oa = true||Gold|
|Host_type = “Publisher” and CC-Lizenz||Hybrid|
|Host_type = "Repository" and Version = "publishedVersion"||Green published|
|Host_type = "Repository" and Version = "acceptedVersion"||Green accepted|
|Host_type = "Repository"||Green submitted|
|Host_type = "Publisher" and keine CC-Lizenz||Bronze|
The OA categories are assigned exclusively. As soon as an open access category has been assigned, the checking procedure is cancelled. This means that the procedure does not allow for multiple classifications such as “green” and “closed” for the same document.
Piwowar et al. (https://peerj.com/articles/4375/) define the different OA categories as follows:
- Gold: Published in an open-access journal that is indexed by the DOAJ.
- Green: Toll-access on the publisher page, but there is a free copy in an OA repository.
- Hybrid: Free under an open license in a toll-access journal.
- Bronze: Free to read on the publisher page, but without a clearly identifiable license.
- Closed: All other articles.