Unwrapping discovery: the importance of institutional repositories

Publisher open access (OA), also known as gold OA, for research papers is easy to understand: the final published version of a journal article is available to anyone with an internet connection, with the authors able to choose their preferred reuse permissions via a Creative Commons (or other) licence.

However, not all journal articles can be published open access, typically because there is a publishing fee that the author, institution or funder can’t or won’t pay.

The legal alternative route to OA is self-archiving, also known as green or repository open access. Institutional repositories are online archives that collect and disseminate the research outputs of a university or research centre, whereas subject repositories aggregate literature from a specific field (for example, PubMed Central for biomedical and life sciences). These repositories are well indexed, and content can be discovered through search engines such as Google and accessed directly from university websites.

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With self-archiving, the author uploads a copy of their article to an institutional or subject repository; this is generally the author-accepted manuscript (AAM) rather than the final published version. It is the version incorporating any changes resulting from peer review but without any publisher branding. Historically, many publishers have insisted on an embargo of six to 48 months before the AAM can be made openly available.

The Research Excellence Framework (REF) in 2021 was a key driver for self-archiving in the UK. The REF is used to assess the quality of university research, with about £2 billion a year allocated to institutions based on their performance. REF 2021 included a requirement for author-accepted manuscripts to be deposited in a repository in order for the article to be eligible for inclusion. Self-archiving is becoming an integral part of funder and institutional open access policies.

Does anyone read copies of articles from institutional repositories?

Yes! It is a misconception that readers are interested in reading open access content only directly from journal websites.

We run sessions on open access for postgraduate researchers and staff and include download statistics for repositories in the UK and our institution to highlight the use of self-archived versions. I always find the figures staggering: there were more than 37 million individual journal article downloads from institutional repositories in the UK during 2023. (Of those, 825,885 came from the University of Southampton repository, with monthly article downloads exceeding 55,000 downloads per month.)

These figures are just for journal articles. If you include theses, datasets, book chapters, working papers and all the other item types added to UK institutional repositories, the cumulative total for 2023 is over 65 million.

Who is reading these self-archived journal articles, and how do they find them?

Self-archiving in a repository significantly boosts citation counts, according to a 2022 paper in Scientometrics, but more interestingly, a 2024 study by researchers from Curtin University and Victoria University of Wellington found that self-archiving widened the diversity of users accessing scholarly content. Access via repositories had a larger effect on the diversity of citing countries, regions and fields of research than publisher open access.

Subscription databases used for literature searching, including Scopus and Web of Science, have filters showing self-archived, or “green”, open access content. Google Scholar also pulls content from repositories, and I love the Unpaywall Chrome extension for instantly checking if an article is available via any legal open access route, either on the publisher webpage or via a repository.

Isn’t the repository version inferior to the final published version?

The AAM is the version of the paper that all authors agree is ready to be published, incorporating all changes resulting from peer review. In this important respect, it is identical to the final “version of record” published in the journal, just without the nice branding. When publishers talk about the added value they provide, I argue that the key elements are high editorial standards and ensuring robust, quality peer review rather than typesetting.

A 2023 paper, by researchers from Las Palmas de Gran Canaria and La Laguna universities, suggested that self-archiving in a repository significantly boosted citation counts, giving such articles 50 per cent more citations than their paywalled counterparts.

The institutional repository record links out to the final published version of the article, and the citation is to the publisher version. It’s a win-win situation for the author and the reader.

Surely self-archiving means ‘delayed’ open access?

Not any more! It is true that until a few years ago, most AAMs uploaded to repositories were subject to an embargo enforced by the publisher. This meant that for STEM articles, there could be a six- to 12-month delay before the AAM could be made openly available, and for arts, humanities and social sciences, the wait could be as long as two years.

Since 2021, funders and institutions have launched rights-retention policies to support authors to legally share their articles without restriction – after all, that’s why we research. The author maintains copyright of the AAM by including a rights-retention statement in their submission, while the publisher has copyright of the final version if the article is published behind a paywall. Authors have the weight of their funders and institutions behind them, with new “read and publish” agreements with journal publishers in the UK typically containing a clause enabling rights retention.

Everyone can publish without paying a fee, and everyone can read – and even more importantly – build on research without paying to access it.

Nicki Clarkson is an engagement librarian at the University of Southampton.

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