Towards a Plan S gap analysis? (1) Open access potential across disciplines

(NB this post is accompanied by a second post on presence of full gold open access journals in Web of Science and DOAJ)

In the proposed implementation guidelines for Plan S, it has become clear there will be, for the coming years at least, three ways to open access (OA) that are compliant with Plan S:

  • publication in full open access journals and platforms
  • deposit in open access repositories of author accepted manuscript (AAM) or publisher version (VOR)
  • publishing in hybrid journals that are part of transformative agreements

Additional requirements concern copyright (copyright retention by authors or institutions), licensing (CC-BY, CC-BY-SA or CC0), embargo periods (no embargo’s) and technical requirements for open access journals, platforms and repositories.

In the discussion surrounding plan S, one of the issues that keeps coming back is how many publishing venues are currently compliant. Or, phrased differently, how many of their current publication venues researchers fear will no longer be available to them.

However, the current state should be regarded as a starting point, not the end point. As Plan S is meant to effect changes in the system of scholarly publication, it is important to look at the potential for moving towards compliance, both on the side of publishers as well as on the side of authors.

To get a first indication as to what that potential for open access is across different disciplines, we looked at a particular subset of journals, namely those in Web of Science. For this first approach we chose Web of Science because of its multidisciplinary nature, because it covers both open and closed journals, because it has open access detection and because it offers subject categories and finally, because of its functionality in generating and exporting frequency tables of journal titles. We fully recognize the inevitable bias related to using Web of Science as source, and address this further below and in an accompanying blogpost.

For a number of (sub)disciplines, we identified the proportion of full gold, hybrid and closed journals in Web of Science, as well as the proportion of hybrid and closed journals that allows green open access by archiving AAM/VOR in repositories.  We also looked at the number of publications from 2017 (articles & reviews) that were actually made open access (or not) under each of these models.

Some methodological remarks:

  • We used the data available in Web of Science for OA classification at the article level. WoS uses Unpaywall data but imposes its own classification criteria:
    • DOAJ gold: article in journal included in DOAJ
    • hybrid: article in non-DOAJ journal, with CC-license
      (NB This excludes hybrid journals that use a publisher-specific license)
    • green: AAM or VOR in repository 
  • For journal classification we did not use a journal list, but we classified a journal as gold, hybrid and/or allowing green OA if at least one article from 2017 in that journal was classified as such. This method may underestimate:
    • journals allowing green OA in fields with long embargo’s (esp. A&H)
    • journals allowing hybrid or green OA if those journals have very low publication volumes (increasing the chance that a certain route is not used by any 2017 paper)
  • We only looked at green OA for closed articles, i.e. when articles were not also published OA in a gold or hybrid journal.
  • Specific plan S criteria are not (yet) taken into account in these data, i.e. copyright retention, CC-BY/CC-BY-SA/CC0 license, no embargo period (for green OA) and being part of transformative agreements (for hybrid journals)
  • For breakdown across (sub)disciplines, we used WoS research areas (which are assigned at the journal level). We combined Physical Sciences and Technology into one to get four major disciplines. In each major discipline, we identified 10 subdisciplines  with the highest number of articles & reviews in 2017 ((excluding ‘other topics’ and replacing Astronomy & Astrophysics for Mechanics because of specific interest in green OA in Astronomy & Astrophysics)
  • We used the full WoS Core collection available through our institution’s license, which includes the Science Citation Index Expanded (SCIE), the Social Sciences Citation Index (SSCI), the Arts & Humanities Citation Index (AHCI) and the Emerging Sources Citation Index (ESCI).

All data underlying this analysis are available on Zenodo:


As seen in Figure 1A-B, the proportion of full gold OA journals is relatively consistent  across major disciplines, as is the proportion of articles published in these journals. Both are between 15-20%. Despite a large proportion of hybrid journals in Physical Sciences & Technology and Life Sciences & Medicine, the actual proportion of articles published OA in hybrid journals is quite low in all disciplines. The majority of hybrid journals (except in Arts & Humanities) allow green OA, as do between 30-45% of closed journals (again except in Arts&Humanities). However, the actual proportion of green OA at the article level is much lower. As said, embargo periods (esp. those exceeding 12 months) might have an overall effect here, but the difference between potential and uptake remains striking.


Fig 1A-B. OA classification of journals and publications (Web of Science, publication year 2017)

Looking at subdisciplines reveals interesting differences both in the availability of open access options and the proportion of articles & reviews using these options (Fig 2).

  • In Physical Sciences and Technology, the percentage of journals that is fully gold OA is quite low in most fields, with slightly higher levels in energy fuels, geology, optics and astronomy. Uptake of these journals is lower still, with only the optics and geology fields slightly higher. Hybrid journals are numerous in this discipline but see their gold and green open access options used quite infrequently. The use of green OA for closed journals, where allowed, is also limited, with the exception of astronomy.  (but note that green sharing of preprints is not included in this analysis). In all fields in this discipline over 25% of WoS indexed journals seem to have no open options at all. Of all subdisciplines in our analysis, those in the  physical sciences fields display the starkest contrast between the ample OA options and their limited usage.
  • In Life Sciences & Biomedicine, penetration of full gold OA journals  is higher than in Physical sciences, but with starker differences, ranging from very low levels in environmental science and molecular biochemistry to much higher levels for general internal medicine and agriculture. In the Life sciences and Biomedicine discipline, uptake of gold OA journals is quite good, again especially in general internal medicine. Availability of hybrid journals is quite high but their use is limited; exceptions are cell biology and cancer studies that do show high levels of open papers in hybrid journals. Green sharing is a clearly better than in Physical sciences, especially in fields like neurosciences, oncology and cell biology (likely also due to PMC / EuropePMC) but still quite low given the amount of journals allowing it.
  • In Social Sciences there is a large percentage of closed non-hybrid subscription journals, but many allow green OA sharing. Alas the uptake of that is limited, as far as detected using Unpaywall data. In this regard the one exception is psychology, with a somewhat higher level of green sharing. Hybrid OA publishing is available less often than in Physical Sciences or Life Sciences, but with relatively high shares in psychology, sociology, geography and public administration. The fields with the highest shares of full gold OA journals are education, linguistics, geography and communication, with usage of gold in Social Sciences more or less corresponding with full gold journal availability.
  • In Arts & Humanities, the most striking fact is the very large share of journals offering no open option at all. Like in Social Sciences, usage of gold across Humanities fields more or less corresponds with full gold journal availability. Hybrid options are limited and even more rarely used, except in philosophy fields. Green sharing options are already limited, but their use is even lower.

PT 1-2 large

LM 1-2 largeSOC 1-2 large

AH 1-2 large

Fig 2. OA classification of journals and publications in different subdisciplines (Web of Science, publication year 2017)

Increasing Plan-S compliant OA 

Taking these data as a starting point (and taking into account that the proportion of Plan S compliant OA will be lower than the proportions of OA shown here, both for journals and publications), there are a number of ways in which both publishers and authors can increase Plan S-compliant OA (see Fig 3):

  • adapt journal policies to make existing journals compliant
    (re: license, copyright retention, transitional agreements, 0 embargo)
  • create new journals/platforms or flip existing journals to full OA (preferably diamond OA)
  • encourage authors to make use of existing OA options (by mandates, OA funding (including for diamond OA) and changes in evaluation system)

We also made a more detailed analysis of nine possible routes towards plan S-compliance (including potential effects on various stakeholders) that might be of interest here.

Towards compliancy

Fig 3. Ways to increase Plan S-compliant OA

Towards a gap analysis? Some considerations

In their implementation guidance, cOAlition S states it will commission a gap analysis of Open Access journals/platforms to identify fields and disciplines where there is a need to increase their share. In doing so, we suggest it would be good to not only look at the share of currently existing gold OA journals/platforms, but view this in context of the potential to move towards plan S compliance, both on the side of publishers and authors. Filling any gaps could thus involve supporting new platforms, but also supporting flipping of hybrid/closed journals and supporting authors in making use of these options, or at least considering the effect of the latter two developments on the expected gap size(s).

Another consideration in determining gaps is whether to look at the full landscape of (Plan S-compliant) full gold journals and platforms, or whether to make a selection based on relevance or acceptability to plan S-funded authors, e.g.  by impact factor, by inclusion in an ‘accepted journal list’ (e.g. the Nordic list(s) or the ERA-list) or by other criteria. In our opinion, any such selection should be presented as an optional overlay/filter view, and preferably be based on criteria other than journal prestige, as this is exactly what cOAlition S wants to move away from in the assessment of research.  Some more neutral criteria that could be considered are:

    • Language: English and/or at least one EU language accepted?
    • Content from cOAlition S or EU countries?
    • Readership/citations from cOAlition S or EU countries?
    • Editorial board (partly) from cOAlition S or EU countries?
    • Volume (e.g. papers per annum)

Of course we ourselves already made a selection by using WoS, and we fully recognize this practical decision leads to limitation and bias in the results. For a further analysis of inclusion of DOAJ journals in WoS per discipline, as well as the proportion of DOAJ journals in ESCI vs SCIE/SSCI/AHCI, see the accompanying blogpost ‘Gold OA journals in WoS and DOAJ‘.

To further explore bias in coverage, there are also other journal lists that might be worthwhile to compare (e.g. ROAD, EZB, JournalTOCs, Scopus sources list). Another interesting initiative in this regard is the ISSN-GOLD-OA 2.0 list that provides a matching list of ISSN for Gold Open Access (OA) journals from DOAJ, ROAD, PubMed Central and the Open APC initiative. It is especially important to ensure that existing (and future) publishing platforms, diamond OA journals and overlay journals will be included in any analysis of gold OA publishing venues. One initiative in this area is the crowdsourced inventarisation of (sub)areas within mathematics where there is the most need for Fair Open Access journals.

There are multiple ways in which the rough analysis presented here could be taken further. First, a check on specific Plan S compliant criteria could be added, i.e. on CC-license type, copyright retention, embargo terms, and potentially on inclusion of hybrid journals in transitional agreement. Many of these (though not the latter) could be derived from existing data, e.g. in DOAJ and SherpaRomeo. Furthermore, an analysis such as this would ideally be based on fully open data. While not yet available in one interface that enables the required filtering, faceting and export functionality,  a combination of the following sources would be interesting to explore:

  • Unpaywall database (article, journal, publisher and repository info, OA detection)
  • (article, journal, affiliation and funder info, integration with Unpaywall)
  • DOAJ (characteristics of full gold OA journals)
  • SherpaRomeo (embargo information)

Ultimately, this could result in an open database that would allow multiple views on the landscape of OA publication venues and the usage thereof, enabling policy makers, service providers (including publishers) and authors alike to make evidence-based decisions in OA publishing. We would welcome an open (funding) call from cOAlition S funders to get people together to think and work on this.


2 thoughts on “Towards a Plan S gap analysis? (1) Open access potential across disciplines

  1. Pingback: New Article/Blog Post: “Towards a Plan S Gap Analysis: Open Access Potential Across Disciplines” | LJ infoDOCKET

  2. Pingback: Towards a Plan S gap analysis? (2) Gold open access journals in WoS and DOAJ | Innovations in Scholarly Communication

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