Papermills prefer Open Access

Adam Day
3 min readMar 11, 2024


TL;DR: the rate of Papermill Alarm alerts is significantly higher in gold OA content than it is in subscription content. If you’re concerned about papermills, Clear Skies offers the Papermill Alarm: the world’s leading papermill detection tool. Get in touch for a demo.

I’m a big believer in Open Science. It wouldn’t have been possible to build Clear Skies, or the services we offer, if we didn’t have free and open scientific resources like Crossref, RoR, ORCID and OpenAlex. Resources like these are critical infrastructure. If they weren’t open, they couldn’t be.

A map of milled papers. Grey dots are random papers to create a map. Coloured dots are known-milled papers. The colours tell me the source of the data. For example; green is Smut Clyde & yellow is Anna Abalkina.

I often need to read papers relevant to my work. These days, so much content is Open Access (OA) that it’s easy to forget what it was like before and to take for granted how it is now. Before OA, if you didn’t have a subscription, getting access to content was a nightmare.

One long-standing criticism of Open Access is that, if readers aren’t paying, the publisher has less incentive to serve them quality content. In an author-pays model, the author is the customer. If the value delivered by publication is just a line on the author’s CV, then content isn’t king, author-service is.

There are excellent OA journals and I don’t think that it would be fair to make a sweeping characterisation of the OA movement as “just selling authors lines for their CVs”. But, if you consider that papermills absolutely are in the business of selling authors lines on their CVs, you can see that that might align better with an author-service business model.

That might partly explain what we’re seeing here, but hopefully I’ve made it clear that the explanation isn’t simple.

Papermill analysis

Quick reminder: if you’re concerned about papermills, Clear Skies offers the Papermill Alarm: the world’s leading papermill detection tool. Get in touch for a demo.

Recently, I shared some analysis from a study that I did last year. This showed a rough lower-bound estimate of the rate of papermilling over the years. I’m going to break that same estimate down into 2 categories defined by OpenAlex. Subscription content and gold OA content. There are uncertainties in this analysis, but the difference is so stark that I think we can conclude that the rate of papermilling in Gold OA journals is higher than in subscription journals.

Here’s the growth of papermill-alarm alerts for subscription content. OpenAlex labels this ‘closed’. Note the truncated y-axis.

And here’s the growth of papermill-alarm alerts for gold OA content. (Again, note the y-axis.)

  • The headline rate of red alerts in all content in 2022 is around 1.8%.
  • The rate of red alerts in subscription content is also around 1.8%.
  • The rate of red alerts in gold OA is 3.4%.

It’s clear that papermills target OA journals. Again, I think that there are a lot of reasons for that.

  • An author-service-focused journal might have faster processing times. That’s a selling point for papermills.
  • Then there are OA mandates. Authors are increasingly required by funders and institutions to publish in OA journals. In such cases, a papermill may be limited in the venues they can target.

I can also see good reasons to target subscription journals.

  • Publication in subscription journals is free, so that gives the mills lower costs.
  • If you don’t want your papers to get discovered, you can hide them behind a paywall. It’s still a line on the CV after all!

And, of course, they might target any journal simply because it accepted their work in the past.



Adam Day

Creator of Clear Skies, the Papermill Alarm and other tools #python #machinelearning #ai #researchintegrity