Fig 1.
Percentage of preprints in Europe PMC posted yearly between 2013–2023.
For each year the number of preprints in Europe PMC is divided by the total number of research articles, including preprints and PubMed journal articles published in the same period. Accessed 8 April 2024.
Fig 2.
Preprints comprise a significant portion of COVID-19 research.
(A) Percentage of COVID-19 preprints (in blue) and COVID-19 journal articles (in green) available in Europe PMC by month. This data includes preprints that have been subsequently published as a journal article. (B) Percentage of COVID-19 journal articles preceded by a preprint (in teal). Accessed 8 April 2024.
Table 1.
The list of preprint servers indexed in Europe PMC.
Table 2.
Methods of PDF/metadata retrieval for full text preprints by server.
Table 3.
Preprint versioning type and version availability in Europe PMC by server.
Table 4.
Preprint review groups with review information in Europe PMC.
Fig 3.
Europe PMC search filters for preprints, journal-published preprints, and reviewed preprints.
Screenshot of the Europe PMC search results shown for a (Single-cell RNA expression profiling of ACE2) query with the Preprints filter on (A). When the ‘Preprints’ filter is selected, additional sub-filters are displayed: ‘Journal published’ filter (B) for preprints with an associated journal published version and ‘Reviewed’ filter (C) for preprints with associated reviews and evaluations.
Fig 4.
Display of preprints in search results (top) and on the preprint record page (bottom) in Europe PMC.
The top figure displays a screenshot of the Europe PMC search results page for a (cognitive decline in TDP-43 proteinopathy) query. The bottom figure displays a screenshot of the Europe PMC preprint page for the PPR596760 record. (A) Preprints in search results are labelled with a green ‘Preprint’ tag that also displays version number. (B) The green ‘Preprint’ tag and (C) a yellow banner indicate that the record being viewed is a preprint. (D) Hovering over the question mark in the banner evokes a pop-up with additional information about preprints. (E) Preprint version history with hyperlinks and publication dates for previous versions.
Fig 5.
Number of preprint records that have more than one version in Europe PMC.
This graph displays the number of preprints for which the latest version available is version 2 or higher. The data presented in this graph excludes preprints from servers that issue a single identifier for all versions. Accessed 8 April 2024.
Fig 6.
Preprint–journal article links in Europe PMC.
Screenshots of the information banner on the preprint page with a link to the published journal article (A) and corresponding banner on the journal article page with a link to the latest preprint version (B). A graph showing the percentage of preprints with an associated journal published version in Europe PMC between 2013–2023 (C). The data presented here includes Open Research Platforms, such as F1000 Research, Access Microbiology, etc. Accessed 8 April 2024.
Fig 7.
Display or removed and withdrawn preprints in Europe PMC.
Warning banners for removed preprint (A), withdrawn preprint (B), and preprint version preceding a withdrawn preprint (C).
Fig 8.
Preprint record display in Europe PMC.
Screenshot of the preprint page for the PPR130125 record. (A) Preprint abstract, as well as figures and full text, where available, are accessible from the navigation panel on the left. The same panel provides access to additional sections with links to related content (B), such as ‘Citations & impact’, ‘Data’, ‘Reviews and evaluations’, and ‘Funding’. The navigation panel on the right provides options to ‘Get citation’, ‘Open PDF’, or ‘Claim to ORCID’ (C).
Fig 9.
Linking reviews to preprints in Europe PMC.
Information banner for a reviewed preprint (A) and a preprint posted on an Open Research platform (B). (C) Information banner and version history indicate that reviews and evaluations are available for a later version of a preprint. (D) Screenshot of the ‘Reviews and evaluations’ section for the PPR279548 record.