Demystifying Plan S

Table of Contents

• Introduction
• The Core Principles of Plan S
• Compliance Routes: The Three Pillars
  • Route 1: Publishing in an Open Access Journal or Platform (The “Gold” Route)
  • Route 2: Publishing in a Journal Under a Transformative Arrangement
  • Route 3: Publishing via an Open Access Repository
• The Financial Realities: APCs and Transformative Agreements
• Impact on Researchers and Research Culture
• Challenges and Criticisms
• Technological Underpinnings and Future Trends
• Conclusion

Introduction

Plan S was launched in 2018 by a coalition of research funding organizations known as cOAlition S. The original mandate was to accelerate the transition to full and immediate open access for scholarly publications. It’s a bold, disruptive, and arguably long-overdue attempt to change how publicly funded research is disseminated fundamentally. 

For years, the traditional subscription model, in which publishers lock content behind paywalls, has been criticized for hindering scientific progress (especially in developing nations) and for forcing institutions to pay exorbitant fees for access to research they often funded in the first place. Plan S steps into this fray not with a gentle suggestion, but with a firm, non-negotiable set of requirements.

To understand Plan S, you need to appreciate the current landscape. Academic publishing is a multi-billion-dollar industry, dominated by a handful of major players who have built their business models on the labor of academics (who write, review, and edit mostly for free) and the public purse (which funds the research and then pays for access to the final papers). It is a peculiar system. Plan S seeks to break this cycle by mandating that all scholarly articles resulting from research funded by cOAlition S members must be published in compliant open access venues. 

This isn’t just about making papers free. Rather, it’s about making them immediately and openly available under a Creative Commons license (typically CC BY), which permits maximum reuse. The implications for researchers, universities, learned societies, and commercial publishers are massive, necessitating a complete overhaul of established practices.

The initial announcement and subsequent rollout of Plan S have generated debate, anxiety, and strategic maneuvering. Some view it as a necessary and righteous crusade against the profiteering of major publishers. Others see it as an unworkable, restrictive, and potentially damaging policy that could destabilize societies and fragment the research ecosystem. Regardless of where one stands, ignoring Plan S is simply not an option. Its influence, backed by significant research funding, is already rippling through journal policies, institutional strategies, and publishing technologies.  

The Core Principles of Plan S

Plan S is built on several core principles that articulate cOAlition S’s vision. These principles are not merely guidelines. They are the philosophical underpinning of a mandate designed to ensure that publicly funded research is treated as a public good. It is a statement of intent that leaves little room for ambiguity about the desired end state. The principles emphasize immediate access, robust licensing, transparency, and a shift away from journal prestige as the sole measure of research quality.

One important aspect of Plan S is the requirement for immediate open access. This means no more embargo periods, which have historically been a common feature of green open access policies where the final accepted manuscript is made available after a delay (often 6 to 12 months). Plan S insists on “zero embargo,” ensuring the research is accessible the moment it is published. 

Under Plan S, scholarly publications must be made available under an open license, with the Creative Commons Attribution license (CC BY) as the preferred standard. The CC BY license is key because it permits not just reading but also reuse, adaptation, and data mining of the content, provided the original author is credited. This is where open access gets its real muscle.

Mandates on licensing and repository deposits are equally important. Plan S stipulates that authors retain copyright to their publications and that any article must be immediately deposited in an open access repository, in addition to being published in a compliant journal. This dual-route approach gives authors and institutions control over the dissemination of their work, insulating them from the potential instability of a single publishing venue. 

Another pivotal aspect focuses on transparency in publication costs and services. cOAlition S is deeply skeptical of the opaque pricing models of major publishers, particularly concerning Article Processing Charges (APCs). The principle demands that publishers clearly state the services provided and the corresponding costs, allowing funders and institutions to assess value for money.

Finally, principles cover important areas such as the role of institutional repositories, support for diverse business models beyond APCs, and the disavowal of the Journal Impact Factor (JIF) as a funding or assessment criterion. This last point is a significant cultural shift. By stating that the intrinsic merit of the work, not the venue of publication, should guide assessment, cOAlition S is directly challenging the established hierarchy of journals. 

They explicitly encourage funders, universities, and research institutions to change their hiring, promotion, and funding criteria to align with this principle. These ten tenets collectively form a comprehensive strategy for a fundamental change in scholarly communication, moving the focus from exclusive subscription to inclusive, immediate, and reusable open access.

Compliance Routes: The Three Pillars

To comply with the Plan S mandate, authors funded by cOAlition S organizations have three primary routes for publishing their work. These routes are designed to offer flexibility while ensuring the core principles of immediate open access and open licensing are met. Understanding these routes is critical for researchers planning where to submit their next paper.

Route 1: Publishing in an Open Access Journal or Platform (The “Gold” Route)

The first (and most straightforward) route is publishing in an open access journal or on an open access publishing platform. The journal or platform must be fully open access, and the articles must be published under a CC BY license. This model typically involves the author or their institution paying an APC to cover publication costs. The journal makes all content immediately and permanently free to read for everyone. 

For cOAlition S, this is the preferred long-term solution, as it aligns completely with the goal of open access publishing. This ensures that the journal is truly open access, subject to proper peer review, and operates ethically. The catch, of course, is the often-high cost of APCs, which has raised concerns about equity and the potential for APCs to simply replace subscription fees, shifting the financial burden from libraries to researchers and funders.

Route 2: Publishing in a Journal Under a Transformative Arrangement

The second route facilitates the transition of subscription journals toward full open access. This is the Transformative Agreement (TA) route. A TA is a contract negotiated between a research institution/consortium and a publisher that converts the former subscription expenditure into a payment covering both subscription access to the publisher’s entire portfolio and the APCs for the institution’s authors to publish open access in that publisher’s journals. 

In essence, libraries are “flipping” the money they once spent on reading into publishing expenditures. The agreements are designed to be temporary, with the goal that the publisher’s journals will eventually transition to fully open access. To be Plan S-compliant, the agreements must meet specific, strict criteria, including a clearly defined end date for the transition and mechanisms to discourage cost increases. 

This route has been instrumental in securing compliance from major commercial publishers, allowing researchers to continue publishing in high-impact journals while meeting the mandate. While highly successful in Europe, this model faces geographical and financial hurdles in global adoption.

Route 3: Publishing via an Open Access Repository

The third route, which has perhaps been the most contentious, is publishing in any journal (subscription or open access) and then securing immediate open access via a repository (often an institutional repository). Historically, this “green OA” route was limited by publisher embargo periods. Plan S’s innovation here is the Rights Retention Strategy (RRS). 

The RRS mandates that, as a condition of receiving cOAlition S funding, the authors must grant a prior license to their Author Accepted Manuscript (AAM) or Version of Record (VoR) immediately upon publication. Specifically, authors must apply a CC BY license to the AAM, which is the version of the paper after peer review and final author revisions but before the publisher’s copyediting and formatting.

This strategy legally overrides any subsequent, more restrictive publishing agreement the author might sign with a journal. This means that, irrespective of the journal’s standard embargo policy, the author’s institution or a central repository can legally upload the AAM with a CC BY license and make it immediately available. This route is a powerful lever for change, as it allows researchers to publish in their preferred journals while simultaneously complying with the open access mandate. It directly challenges the publisher’s claim to exclusive rights over the accepted manuscript and is a key mechanism for accelerating open access where the other two routes are not yet viable.

The Financial Realities: APCs and Transformative Agreements

The shift to open access fundamentally changes the financial flows of scholarly communication, moving away from a ‘pay-to-read’ model funded primarily by library subscriptions to a ‘pay-to-publish’ model that relies heavily on APCs. Plan S has been forced to grapple with the complex financial realities this transition creates. The price of an APC for a high-prestige journal can easily exceed $5,000, creating an immediate and serious financial barrier for researchers without robust funding or institutional support. 

cOAlition S acknowledges the potential for APCs to simply replicate the exclusivity of the subscription model in a new form. Their response has been multifaceted. Firstly, Plan S mandates transparency. Publishers that charge APCs must detail what services are covered by that charge (e.g., peer review management, copyediting, hosting, indexing, archiving). This is intended to curb excessive pricing and allow institutions to negotiate based on clear value. 

Secondly, cOAlition S has put a strong emphasis on TAs as a necessary, albeit temporary, transitional mechanism. The TAs are designed to ensure that the total money spent on reading and publishing open access does not exceed the amount previously spent solely on subscriptions, ideally leading to cost savings over time as the market adjusts.

However, TAs are controversial. While they allow many researchers to publish open access without individual APC payments, they have been criticized for entrenching the dominance of the largest publishers, making it difficult for smaller, non-profit, or university-press publishers to compete. Critics argue that TAs merely re-bundle the costs and complexity, failing to address the fundamental issue of high publisher profit margins. Furthermore, while TAs work well for institutions in well-funded regions like Europe and North America, they offer little relief to the rest of the world that lacks deep pockets.

The ultimate aim of cOAlition S is to promote a diversity of non-APC-based models in the long run. They strongly support diamond open access, in which neither the author nor the reader pays, with publishing costs subsidized by institutions, governments, or endowments. They fund and champion various initiatives focused on developing sustainable, non-commercial open access infrastructure. The financial journey is far from over, and the tension between the immediate need for compliance and the long-term goal of an equitable, affordable open access ecosystem remains one of Plan S’s most pressing challenges.

Impact on Researchers and Research Culture

Plan S is not just a publishing policy. It’s a culture-changing intervention. For the individual researcher, the mandate directly affects where they can publish, how they manage their intellectual property, and even how their career progression is evaluated. The initial reaction from many researchers was one of confusion and anxiety, often centered on the potential loss of the ability to publish in high-prestige journals. These non-compliant journals are often essential for career advancement in a system heavily reliant on Journal Impact Factor (JIF).

The shift from the traditional model requires researchers to become more actively engaged in the legal and technical aspects of publishing. They must understand the nuances of CC BY licenses, the Rights Retention Strategy, and the compliance status of their target journals. For many, this is a significant and unwanted administrative burden. However, the core benefit for the research community is immense: immediate, free access to the global body of publicly funded research. This accelerates discovery, facilitates interdisciplinary work, and is transformative for researchers at institutions that cannot afford the expensive subscription fees charged by publishers. 

A profound impact stemming from the Plan S is the commitment to eliminate the use of the JIF as a measure of research quality. This principle, which aligns with the broader DORA (Declaration on Research Assessment) movement, seeks to shift evaluation toward the paper’s intrinsic merit rather than the perceived prestige of the journal in which it appears. 

While a laudable goal, changing deeply ingrained academic hiring, promotion, and tenure practices is notoriously difficult. University administrators and promotion committees are slow to abandon familiar metrics. cOAlition S is actively pushing institutions to sign DORA and implement narrative-based CVs and other non-JIF-dependent evaluation methods.

This effort is an uphill battle but crucial for the long-term success of the open access movement, as it removes the incentive to prioritize non-compliant, high-JIF journals over fully compliant open access venues. The success of Plan S ultimately hinges on whether the academic community can genuinely embrace a more holistic and quality-driven approach to assessment.

Challenges and Criticisms

Plan S has faced a torrent of criticism and numerous implementation challenges since its inception. The resistance is diverse, coming from commercial publishers, societies, and academics concerned about specific aspects of the mandate. The criticisms generally fall into categories of feasibility, equity, and unintended consequences.

A loud criticisms came from the learned societies, which are often non-profit organizations that use the surplus revenue from their subscription journals to fund scholarly activities, conferences, and grants. Many argued that Plan S would cripple their ability to self-fund by forcing them to choose between their financial stability and compliance. Moving their journals to a fully APC-based open access model is risky and complex for smaller operations, potentially leading to the closure of specialized, high-quality titles essential to niche fields. 

Another challenge is global adoption and equity. The Plan S mandate is primarily driven by well-funded, mostly European and North American organizations. While its goal is global access, the financial mechanisms, particularly APCs and Transformative Agreements, favor the wealthiest institutions. Researchers in the Global South, often without grant funding for APCs, fear they will be marginalized, becoming perpetual readers but rarely able to afford to publish in the newly “gold” open access journals. The Rights Retention Strategy offers a partial workaround, but the underlying funding inequality remains a systemic issue that Plan S alone cannot fully resolve.

Finally, the mandate’s immediate nature and the Rights Retention Strategy itself have been sources of tension with publishers. Publishers argue that the RRS, by unilaterally applying a CC BY license to the Author Accepted Manuscript, constitutes a form of ‘contractual override’ and infringes on their ability to manage their journal content effectively. Many journals have had to adapt their publication workflows and author agreements to accommodate the RRS, often with reluctance. 

The RSS, however, is fundamental to the mandate, as it provides a non-negotiable legal basis for achieving Zero Embargo open access, a core principle that publishers were otherwise unwilling to adopt universally. The ongoing negotiations and adaptations reflect the profound disruption Plan S is designed to cause in the established publishing order.

Technological Underpinnings and Future Trends

The Plan S transition is impossible without advancements in publishing technologies and infrastructure. Open access is not just a policy change. It requires a robust, interoperable, and globally connected technical ecosystem. Publishers and institutions are investing heavily in new platforms and tools to meet the demands for immediate open access, transparent pricing, and repository integration.

One critical technical component is the development of metadata standards and interoperability. For an article to be genuinely open access, it needs to be easily discoverable, harvestable, and linkable. This means rigorous application of Digital Object Identifiers (DOIs) and adherence to standards like the JATS (Journal Article Tag Suite) XML format. 

Repositories must be well-indexed and comply with the OpenAIRE guidelines, a European infrastructure designed to support the monitoring and tracking of open-access publications. The ability to track compliance and expenditure (a key part of Plan S accountability) relies entirely on this seamless technological plumbing. For example, systems need to accurately link a grant number to an author, a published article, the payment of the APC, and the final repository deposit.

The concept of Open Science platforms is another key trend accelerated by Plan S. These are non-journal-based publishing venues that often employ preprints, immediate publication, and post-publication peer review. Platforms like Wellcome Open Research and F1000Research offer rapid dissemination and structured peer review, bypassing the often lengthy submission and acceptance cycles of traditional journals. cOAlition S supports these platforms as compliant publishing venues, encouraging innovation beyond the traditional journal format.

Looking ahead, the future of scholarly publishing, shaped by Plan S, points toward a highly decentralized, more machine-readable environment. There will be a continued move toward modular publishing, where the research paper is broken down into its constituent parts, each separately identified and citable. Furthermore, AI and machine learning will become increasingly vital for data mining the vast corpus of immediately available open access content, leading to new forms of research synthesis and discovery. In short, Plan S is pushing the entire system toward a more technologically sophisticated and globally interconnected knowledge infrastructure, ensuring that technology facilitates rather than hinders the free flow of research.

Conclusion

Plan S aims to be that one powerful, funder-led attempt to correct the historical anomaly where publicly funded research was locked behind commercial paywalls. Through its core principles and compliance routes, cOAlition S is systematically dismantling the old subscription model and establishing immediate, open access under a CC BY license as the new standard for funded research. This is not a gentle nudge but rather a clear, decisive, and non-negotiable policy mandate.

The initiative has created undeniable momentum. It has forced major publishers to embrace Transformative Agreements, significantly increasing the volume of open access content globally. Crucially, by championing the Rights Retention Strategy, Plan S provides a mechanism for authors to achieve compliance even when publishing in non-open-access journals, securing the public’s right to immediate access regardless of the publisher’s business model. It has also helped revitalize the conversation around research assessment, pushing institutions away from reliance on the Journal Impact Factor toward a greater focus on the intrinsic quality of the research itself.

Yet, serious challenges remain. Issues of cost, equity, and the sustainability of publishing models for smaller societies must continue to be addressed. The global transition to a truly open, affordable, and equitable scholarly communication system is a marathon, not a sprint. 

Plan S is a foundational leap forward, creating the legal and financial scaffolding necessary for this new ecosystem. Its ultimate success will depend on the continued commitment of funders, the strategic adaptation of institutions, and, most importantly, the research community’s willingness to embrace and utilize the new freedom it provides.