Delta Think’s OA Market Sizing shows that the open access market continues to grow faster than the underlying journals publishing market, and faster than we previously expected. (Market Size represents revenue generated by providers or, conversely, costs incurred to buyers of content.) We estimate it to have been worth $675m in 2018 and on track to grow to over $758m in 2019.

Headline numbers

Updates to key industry indexes are released over the summer, and we combine these with benchmarks obtained from our publisher survey to size the market. Our models, examined in greater depth within the main Open Access Data & Analytics Tool, suggest these headlines for sizing:

In 2017, the global OA market was worth around USD $588m and grew to around $675m in 2018.

  • The 15% increase between 2017 and 2018 is larger than the growth in the underlying scholarly journals market, which is typically low to mid-single digit.
  • Trends in the data suggest that the growth rate in open access has been falling over previous years and will fall over the coming years to 10%-12% annually, but will remain above the underlying market rates. The open access market is on target for over $758m in 2019.
  • Just under 30% of all scholarly articles are published as paid-for open access, accounting for around 6.4% of the total journal publishing market value.
  • As we explored over the summer, the major selective article indexes suggest that there are around 4,500 fully OA journals, although there is an unindexed long tail of around 20k in the more inclusive indexes.

An important note about our method

We aggregate data from our annual publisher survey – which covers over 50% of indexed global output – and project it to model the entire market. As so few publishers account for such a large proportion of our market’s output and value, we need to compensate for variations exhibited by individual publishers that may not represent underlying trends. The compensation is a balance, as a few large players can move the market, so their variations cannot be ignored completely.

Our results are also sensitive to the models we use to project the market. This year we have moved to using Unpaywall data. Most of the major indexes use it and we believe it is the closest we can get to measuring open access output directly. In our opinion it also represents a more accurate global view of open access due to its more comprehensive sampling than other sources.

As a result, our numbers have changed as compared with our estimates from last year. To uncover underlying trends on a like-for-like basis, we have restated our historic numbers based on our new models.

Finally, we project trends out using “best fit” (aka regression) analysis of historical data points. We have a choice of methods, which may yield more or less aggressive estimates. We choose less aggressive trends to reflect the slow-moving nature of our market, and that underlying growth figures have not changed significantly for many years.

Trends and Drivers

We anticipate a 2018-2021 CAGR of 8.6% in OA output and 11.1% in OA market value. The underlying trends in the data are as follows:

  • Underlying growth is slowing, although it remains in double digits, but is still well ahead of the underlying journals market.
  • As discussed above, the market includes more fully open access articles than we had previously modelled. As we explored last month, just under 30% of global output is open access – excluding green and public access (aka “bronze”). This represents a change to our data from previous years.
  • Less hybrid going forward changes the dynamics. Globally, the strong growth in output appears to be driven by publications in fully OA journals, and this in turn influences the growth of value.
  • Hybrid APCs are higher than those for fully OA, but the gap is narrowing, and both show signs of long-term increases.

The overarching trends do mask important nuances. Individual publishers exhibit different dynamics. This is not surprising given how varied their portfolios can be. However, timing of their output also affects these figures.

  • For example, some publishers in our sample produced less than average in 2018 but made up the shortfall in 2019. Others saw accelerated growth in 2018, driven by increased numbers of articles published and increased prices. As a result, we see fluctuations in the overall numbers while the underlying trends remain consistent.
  • Hybrid proportion and growth varies considerably among publishers and can reflect timing in output or acquisitions.
  • Payments per article vary wildly depending on the sample. For example, the Open APC data suggest higher-than average numbers, reflecting their focus on high-output and European institutions. Meanwhile, some segments of the market may see fully OA APCs that are higher than hybrid APCs (counter to the overarching market averages).
  • Regions vary greatly. Waivers offered to low-GDP countries and how OA is funded are highly variable, and these affect the models as well.


We have highlighted just a few of the trends that our Open Access Data and Analytics Tool explores in depth, including projections of spending and output over the coming 3-5 years. As we have explored, the open access market remains buoyant and set to grow significantly faster than the underlying scholarly journals market.

Open access output now accounts easily for one-third of output (including Green), and even more if you include public access (Bronze). The proportion of money spent on open access continues to lag the proportion of output, but it appears to be gaining ground.

In our view, the twin drivers of cancellations of big deals and the rise of transformative agreements look set to accelerate the spending on open access. Subscription payments will inevitably be squeezed, and fully OA activity is taking an increasing share of value.

That said, we should not forget that ours is a global marketplace. For example, the problems facing scholarly communications in China tend to focus on quality and transparency, rather than cost and access. Meanwhile, many areas of the world with high OA adoption have low GDP and therefore limited effect on global payment averages. Funder mandates, transformative agreements, and cancellations of big deals may have a lesser impact on the OA landscape outside of Europe and North America.

Once OA adoption in the vanguard regions reaches saturation, then we may see growth of full OA slow significantly as the remaining regions show weaker drivers. We mentioned above that we err on the side of conservatism in our projections. But equally mathematically-valid alternatives suggest that OA growth could slow to single digits over the next 4-5 years.

Given researchers’ ambivalence and variations in global policies, OA’s continued phenomenal growth is by no means a given.

This month’s major update to the OA Data and Analytics Tool’s Market Sizing section shows the latest market projections. Our subscribers can see seven years’ data now, including historical trends and future projections for volume and value of the open and subscription access market places – including hybrid break-outs.

Our comprehensive data also shows analysis of growth factors, revenue benchmarks under different business models, adoption of the different types of open access, and a sense for how open access influences impact and citation metrics.

To learn how you can explore this data, contact us at info@deltathink.com to schedule a demonstration.


NIH Requests Public Comment on a Draft Policy for Data Management and Sharing and Supplemental Draft Guidance – November 6, 2019

“The National Institutes of Health (NIH) released a Draft NIH Policy for Data Management and Sharing and supplemental draft guidance for public comment. The purpose of this draft policy and supplemental draft guidance is to promote effective and efficient data management and sharing that furthers NIH’s commitment to making the results and accomplishments of the research it funds and conducts available to the public.”

SPARC Europe releases summary of Open Data Directive and guidance for its implementation – October 31, 2019

“In July of this year, The Directive on open data and the re-use of public sector information, also called the “Open Data Directive” went into effect. To aid in the implementation of this new legislation, of which members states have until 16 July 2021 to transpose, SPARC Europe today is releasing a summary coupled with implementation guidance.”

SCOAP3 extended until 2022 – October 31, 2019

“The SCOAP3 Collaboration announces today that CERN, the European Organization for Nuclear Research, as ‘host organization’ of SCOAP3 has signed contracts with 11 leading commercial and society publishers to extend this large-scale Open Access initiative for a 3rd three-year term, covering the years 2020-2022. With the conclusion of the formal contracts, SCOAP3 will continue supporting authors worldwide to publish their research Open Access at no cost or burden.”

Knowledge Unlatched and ScienceOpen cooperate for better Open Access Analytics
October 25, 2019

“Knowledge Unlatched (KU), the central platform for Open Access (OA) financing models and ScienceOpen, a freely accessible discovery network, cooperate to provide better reading analytics for books and journals funded through KU.”

A View of Plan S from the International Alliance of Research Library Associations
October 24, 2019

“The member organisations of IARLA — LIBER, ARL, CARL, CAUL and RLUK — welcome moves towards an open access environment for journal articles and aligned funder policies to achieve this. We are therefore supportive of the overall objectives of Plan S as published by cOAlition S.”

UC Irvine first campus to launch Presidential OA Policy – October 23, 2019

“This week, UC Irvine became the first UC campus to launch the UC Presidential Open Access Policy implementation, enabling UC Irvine Health Science Clinical Professors and Librarians to join their Academic Senate colleagues in using the UC Publication Management System to make their scholarly articles freely available in eScholarship, UC’s open access repository and publishing platform.”

Open access popular with researchers but full potential remains untapped, says new global study – October 21, 2019

“Researchers are in favor of widening access to research but remain largely unaware of initiatives and services that have been established to encourage growth of open access (OA). New figures released for Open Access Week, reveal little consensus when it comes to permitting reuse of published research. A survey of 2,755 Taylor & Francis authors also finds they are failing to take advantage of the open access options available to them.”

The British Academy publishes new report on open access and book chapters
October 18, 2019

“The British Academy has published a new report exploring the opportunities and challenges of widening open access for book chapters. ‘Open Access and Book Chapters’ was commissioned by UK Research and Innovation (UKRI) to inform future open access policy and to underpin the decisions that UK higher education funding bodies will need to take for the Research Excellence Framework (REF) after REF 2021.”


October 30, 2019

BMJ launches new open access journal on integrated care

“”Leading healthcare knowledge provider BMJ has added a new title to its expanding portfolio of more than 70 specialist journals, with the launch of the Integrated Healthcare Journal. Integrated Healthcare Journal is a new online only Open Access journal co-owned by the Royal Pharmaceutical Society (RPS).”

October 21, 2019

Thieme expands subscription journal for cardiac surgeons by adding open access supplement for pediatric cardiologists

“Thieme is expanding the specialist journal The Thoracic and Cardiovascular Surgeon by adding the new Open Access offering Pediatric and Congenital Cardiology. All contributions to the new supplement are freely accessible online. With this new model, Thieme for the first time integrates an extensive Open Access offering directly into an established subscription journal.”