Quantifying the Growth of Preprint Services Hosted by the Center for Open Science

A wide range of disciplines are building preprint services—web-based systems that enable publishing non peer-reviewed scholarly manuscripts before publication in a peer-reviewed journal. We have quantitatively surveyed nine of the largest English language preprint services offered by the Center for Open Science (COS) and available through an Application Programming Interface. All of the services we investigate also permit the submission of postprints, non-typeset versions of peer-reviewed manuscripts. Data indicates that all services are growing, but with submission rates below more mature services (e.g., bioRxiv). The trend of the preprint-to-postprint ratio for each service indicates that recent growth is a result of more preprint submissions. The nine COS services we investigate host papers that appear in a range of peer-reviewed journals, and many of these publication venues are not listed in the Directory of Open Access Journals. As a result, COS services function as open repositories for peer-reviewed papers that would otherwise be behind a paywall. We further analyze the coauthorship network for each COS service, which indicates that the services have many small connected components, and the largest connected component encompasses only a small percentage of total authors on each service. When comparing the papers submitted to each service, we observe topic overlap measured by keywords self-assigned to each manuscript, indicating that search functionalities would benefit from cutting across the boundaries of a single service. Finally, though annotation capabilities are integrated into all COS services, it is rarely used by readers. Our analysis of these services can be a benchmark for future studies of preprint service growth.