The Preprint Citation Index: linking preprints to the trusted Web of Science ecosystem

After many months of planning, we are launching the Preprint Citation Index™, a multidisciplinary collection of preprints from leading repositories that helps researchers stay current with the newest research while maintaining confidence in the resources they rely on.

With the launch of the Preprint Citation Index, we are making it even easier for researchers to include preprints in their existing research workflows. Users can now locate and link to preprints alongside traditional scholarly literature while working in their preferred search and discovery environment, bringing more visibility to preprints.

With the addition of the Preprint Citation Index, the Web of Science™ can be used as a single portal to search across journals, books, proceedings, datasets and now preprints – streamlining the research process and helping to make important connections faster.

Increasing focus on preprints

In academic publishing, a preprint is a version of a research paper or outcome that is publicly available in a repository before it has been peer reviewed. Preprints have been around since the early ’90s, but the COVID-19 pandemic increased the attention on them by highlighting the importance of shortened publication timelines as well as the challenges of using unreviewed sources throughout the research process.

For researchers focused on today’s urgent global challenges, access to preprints can significantly speed up scientific progress. We’ve created the Preprint Citation Index so researchers can discover and use both preprints and journal articles, on one trusted platform.

The Preprint Citation Index in action

The Preprint Citation Index currently provides nearly two million preprints from arXiv, bioRxiv, chemRxiv, medRxiv and We plan to add preprints from a dozen additional repositories as well as display open peer reviews on Preprint Citation Index throughout 2023.

Our unique, multidisciplinary collection of preprints helps to:

  • Locate versions of record (where applicable) for preprints: Find and reference peer-reviewed articles with links from preprints to Web of Science Core Collection™ records.
  • Connect preprints to journal articles: Uncover connections between cutting-edge preprints indexed in the Preprint Citation Index and journal articles indexed in the Web of Science Core Collection via citation linking.
  • Expand the view of a researcher’s expertise: Place preprints in the context of a researcher’s career with preprints displayed on an author’s Web of Science Researcher Profile.
  • Monitor new research across several repositories: An author can set an alert for keywords or a named researcher of interest to be notified when relevant preprints become available.

Preprint Citation Index and the Web of Science Core Collection: separate but complementary

It’s important to note that the new Preprint Citation Index is a standalone database that provides researchers and graduate students with immediate access to an up-to-date, aggregated and searchable set of preprints linked to Researcher Profiles. Preprints are not included in the Web of Science Core Collection.

To help ensure this is clear within the Web of Science platform, when running an ‘All Databases’ search, the default setting is filtered to exclude preprints – meaning that you will need to ‘opt in’ to include them in your search. This feature can be toggled on and off and saved as a preference. When included in the search, preprints are clearly marked in the search results and full record page with a disclaimer.

Additionally, preprint citations are also not included in Times Cited counts, the Journal Impact Factor™ (JIF) or any other citation metrics within the Web of Science Core Collection or Journal Citation Reports™. We are linking preprints and the scholarly articles they cite, so researchers can find the latest research relating to an article. This link does not display a numerical citation count. Under the Times Cited counts for an article, users can see a link to view citing preprints.

Impact of an integrated research publication ecosystem

We know that searching aggregated preprint content alongside other content sets saves valuable time – streamlining the research process and helping researchers make important connections faster.

We anticipate that discovering preprints in the Web of Science environment will also simplify the process of evaluating preprint quality and trustworthiness by connecting them to the versions of record and linking to other scholarly output from preprint authors.

This new database can also help researchers identify trends in the preprint landscape with the help of standardized metadata, including the ability to analyze preprint output from 2021 onwards by institutional affiliations, regions or funders.

We’re excited to see how researchers will use the Preprint Citation Index to support faster, higher quality research and how this might broaden and strengthen the global research ecosystem – opening doors to a more open, transparent and connected future.

For more information about the Preprint Citation Index, check out our website.