2021 Volume 31 Issue 1 Pages 31-50
This article investigates the state of Open Access (OA) in Japan and the world using a dataset provided by Unpaywall. The analysis covers two million articles for Japan and 80 million articles for the world. We find that the percentages of OA articles in Japan and the world are 41.83% and 29.77%, respectively. A reason for the high percentage in Japan is that many articles published a long time ago belong to the bronze category. As a trend in recent years, the analysis reveals the percentage of articles in the gold category has increased. Regarding the contribution of institutional repositories (IRs) to OA, we observe the percentage of articles available in IRs increased from 2000 to 2010. However, the percentage has been flat, at 5%, since 2010. The percentage of articles that are OA only in IRs is 1.5%. To promote green OA efficiently, it is necessary to enable each institution to grasp its state of OA by e.g., developing a system that continuously monitors levels for each institution.
