Once seen as the gateway to full open access (OA), hybrid journals have either been wildly successful or a total failure. A hybrid journal is when authors can publish a paper in a subscription journal and choose to make it OA, typically by paying an article processing charge (APC).

If the goal of hybrid OA was to facilitate a global flip to full OA, the goal has, at least so far, failed after decades of trying.

If the goal of hybrid OA was to provide options for authors to select OA while still publishing in their preferred journals, then it’s been a roaring success. Let’s look at the numbers.

The number of journals offering hybrid went from 2,000 in 2009 to 10,000 in 2016 with articles growing from 8,000 to 45,000.

While these overall numbers seem high, studies have found that journals offering hybrid on average have at most 10% of the content as OA to as little as 4.3% — meaning, the vast majority of content in most hybrid journals is not supported by APCs and thus, there is no clear level of sustainable financial support to flip the journals to a fully OA models. There are certainly journals offering hybrid OA that have received zero OA requests and others that receive many more.

The danger for a subscription journal offering some papers as APC-supported OA is well documented. Some in the library community complain of “double-dipping.” A journal that reaches a certain threshold of OA content will likely feel pressure to provide offsets, not an unreasonable or uncomplicated expectation.

For the publisher, the only “extra work” needed to make a journal hybrid is to have a way of collecting an APC and ensuring that all licensing and metadata around licensing is clear.

Many publishers, particularly society publishers, sat on the sidelines of offering hybrid OA, especially if their community of authors weren’t asking for an OA option. This changed with the 2013 Finch Report and the promise of widespread availability of APCs for hybrid journals. Not wanting to be left off the list of journals available to receive RCUK funded papers, many publishers added a hybrid OA option.

So here we are, many years into rapid hybrid OA growth, and the number of journals that have successfully flipped has been modest.

I have long argued that multiple business models can, and should, be supported in order to ensure sustainability, as well as providing different research communities with outlets that meet their different needs. The continuing existence of hybrid journals is one element to this balance, particularly for research communities that are not heavily funded through government or philanthropic organizations.

Enter Plan S. According to the list of principles provided by cOAlition S, the funding agencies participating in Plan S intend to disallow publication in hybrid journals. While there may be some sort of “transition” period allowed — a transition from the transition — for journals that have been offering hybrid and have not seen enough uptake of OA to flip their journals, this is certainly a concern.

The size of the concern over losing hybrid depends on a lot of factors for any given publisher or journal. The biggest factor is how many papers a journal is currently receiving from the small number of funding agencies signed on to Plan S. A publisher with only a handful of papers from Plan S agencies may decide to walk away from those authors entirely instead of starting a new OA journal or flipping a subscription journal that has little hope of attracting enough OA submissions to keep it alive.

Another option is to create “mirror journals”. Mirror journals are essentially new journals that piggyback off existing journals for the sole purpose of offering a fully-OA option. Part A of a journal would be the already existing subscription or hybrid journal, and a new journal, part B, would be a fully-OA version of the same title.

These would be separate publications, with separate ISSNs. However, both parts A and B of the journal twins would have the same editorial board, the same aims and scope, and the same editorial peer review policies. Authors would submit their manuscripts through one shared system for peer review. Upon acceptance, the author would be given the choice of publishing the paper in the hybrid original title, or the fully-OA title.

Mirror journals solve several problems:

• These are two journals that can have two separate business models. If one part goes subscription only and the other goes OA only, it’s easier to leave behind the concerns of double-dipping. That said, publishers may want to continue to give authors the maximum amount of choice, meaning non-Plan S funded authors could continue to opt for OA in the established journal as a hybrid model.
• No need for publishers to launch brand new OA journals that are generic in scope and fail to reach specific audiences.
• Any funding mandates for Gold OA are met while still providing authors with the option of publishing in their community journals.
• Separate journals make for cleaner offerings to libraries that may want to add pre-paid or discounted OA fees to their subscription purchase. Mirror journals would be eligible for “Read and Publish”-style arrangements, helping mitigate the additional costs that Plan S members are voluntarily taking on.
• The editorial decision process is separated from the financial model for the journal. Editors don’t know whether an author will choose to pay an APC until after their decision is made, so this reduces economic influences on what gets accepted.

The cost for creating mirror journals seems relatively low — though more than for adding a hybrid offering to an existing journal. Each new part B journal will need its own ISSN and the mirror variant will need to be set up as an independent title on the publishing platform. The platform fees will vary depending on the provider. Journal workflows may need to be adjusted to incorporate the post-acceptance fork. New contract addenda will be needed for any societies working with a publisher partner. Again, this will vary by each journal’s individual situation.

Indexing is still a bit of a mystery in these scenarios. A benefit of hybrid OA is that the journal can make this offering available to authors while maintaining its status on indexing sites like Scopus and Web of Science. But what happens to the Impact Factor when a mirror journal is launched?

It’s not clear whether mirror journals would be considered new publications, or seen as a “split” of an existing journal. Per the rules of splitting journals provided to me by Thomson Reuters in 2015 (since purchased by Clarivate), the journal as a single title keeps its IF in year one. In year two, parts A and B both get Impact Factors based on one year of citation and source counts. Parts A and B get full two-year Impact Factors in year three.

In other words, by year two of the split, the journals will go their separate ways in terms of Impact Factor. The other rule for splitting is that the content and scope of the two new journals (parts A and B) come from the original title. In the case of mirror journals, they would be identical. I did ask Clarivate if these rules would hold true for mirror journals and I received the following response from Nandita Quaderi, Editor in Chief, Scholarly and Academic Research:

Clarivate Analytics cannot determine a general indexing policy position at this stage as no publisher policy has yet been announced. We will respond to any changing situation if, later, a clear outcome is agreed between research publishers and research funding organizations. Our response will be guided by the principles of fairness and editorial balance that have been exercised throughout the development of our citation indices. We look forward to close engagement with all interested parties.

While the answer is theoretical in nature, in practice, some of these journals already exist. The American Mathematical Society has had a “series B” fully-OA version of their transactions journal and their proceedings journal since 2014 (described here).

Elsevier has launched a few journals, one called Water Research X, which has the same board and the same scope as Water Research, and now Journal of Hydrology X with the same model. The submission and review process appears to be the same for both the original and the “X” titles. They do both have different ISSNs.

In theory, for Plan S-funded authors it should not matter if the new title has an Impact Factor given that Plan S specifically calls for adherence to the DORA principles, which eschews the use of Impact Factor in assessing the quality of work of an individual. This will be fine for authors whose career path keeps them under Plan S funding, but may cause problems for international collaborators or researchers who may wish to one day move to areas with different funding and evaluation conditions. At the very least, mirror journals allow Plan S authors to benefit from the existing reputations of the original titles, even if the new OA version’s Impact Factor does not measure up.

Adopting mirror journals will create a whole lot of new journals. It’s been widely reported that up to 85% of the journals that currently exist would be off limits to Plan S-funded authors. Does this mean that we need to duplicate 85% of the world’s journals? Publishers will need to decide which journals would benefit from having a mirror. Again, this may depend on which funders intend to adopt Plan S and what kind of research those agencies fund.

Some colleagues have stressed concern with how the architects of Plan S might respond to mirror journals. Will an organization that has outlawed hybrid OA see this as an attempt to recreate hybrid under a different name? It’s hard to tell. In a recent interview with Richard Poynder, Robert-Jan Smits declared, “It is for publishers to provide Plan S-compliant routes to publication in their journals so that researchers can choose where to publish when accepting funding from those who sign Plan S.” Smits apparently discussed the Elsevier title recently and was reportedly lukewarm to the concept.

While mirror journals seem to fit the bill for publishers enabling “Plan S-compliant routes,” they will not provide the sought after financial relief that seems to motivate the plan for banning hybrid OA as an option. Plan S members would be voluntarily taking on the additional financial burden of paying for their own authors’ OA publications while still having to pay to subscribe to access the research published by the rest of the world.

Some academics have made the argument that academic freedom is being impinged when they cannot choose the appropriate venue for their work. Others have raised concerns about what happens to society publishers in the face of any wide-spread Plan S-like provisions. To that, Smits reportedly stated that societies will need to “bite the bullet and go open access.”

Mirror journals allow for the authors to remain within the journal communities they already support, be it commercial journals or society journals, while still providing a Plan S-compliant avenue for their papers. This may be the only option for many research societies other than shunning Plan S researchers entirely.

As long as APCs are not capped (another principle of Plan S) at a rate lower than what publishers of ALL sizes can afford, mirror journals will stand alone and not be dependent on revenue from the subscription journal. If the OA version fails to displace content from the subscription journal, both versions of the journal will continue to co-exist. If, over time, the majority of content moves over to the fully-OA version, the two titles can eventually be merged back into one.

Putting the considerations for Plan S aside, mirror journals may provide a better path to full OA in that there is no risk with having to flip an already profitable or break-even journal. Both parts of the journal can peacefully co-exist until such time that the OA journal is outpacing the subscription journal making the subscription journal obsolete.