The University of Illinois Libraries’ house one of the largest library collections in the United States, but from time to time scholars may still come across electronic resources to which the Library does not have direct access. Colloquially, this is sometimes referred to as “hitting a paywall.” While the Library’s Interlibrary Loan service provides an excellent resource for obtaining access to materials outside of the Library’s collection, many “paywalled” articles are also available in OA versions.The problem is that discovery systems typically aren’t designed to get a user from a paywalled version of an article to an OA version.
A new browser plug-in from Impactstory called Unpaywall aims to address this issue by pointing users to OA versions of paywalled articles, when available. When a user arrives at a webpage for an article, Unpaywall attempts to find an OA version of the article by searching through open repositories. If the plug-in succeeds in finding an open version, this is indicated with an opened lock icon on the side of the screen. Clicking on this icon takes you to a copy of the article.
Unpaywall can also distinguish between articles that are Gold OA (articles available from the publisher under an OA license) and Green OA (articles on a preprint server or an institutional repository, like IDEALS). This information is indicated by the color of the opened lock icon (Note that this is an option that is not turned on by default).
Unpaywall claims that they succeed in locating open access versions of 65-85% of articles (When an open version is not found, this is indicated with a grey closed lock icon), though librarian blogger liddylib reports a 53% success rate when trying it out on Almetric’s Top 100 Articles of 2016. Nevertheless, Unpaywall seems dedicated to improving their software, as Jason Priem, one of the program’s developers, responded to liddylib’s blog post, reporting that they had improved the product to locate some Gold OA articles that had originally been missed. Unpaywall also encourages users to report bugs.
As mentioned above, Unpaywall locates full text OA articles by using data from oaDOI, another ImpactStory project. oaDOI indexes upwards of 90 million articles. relying on data sources like the Directory of Open Access Journals, CrossRef, DataCite, and BASE. It is important to note that the OA articles to which Unpaywall directs users have all been legally made available. This distinguishes Unpaywall from projects like Sci-Hub, which provide PDFs that are often made available through less credible means.
Unpaywall is a brand new product, and so it is to be expected that some hiccups will occur. Nevertheless, it seems like a promising tool for helping more people get access to research by making open access resources more discoverable.