How many of my thesis references about open access were paywalled?

When I started my Master of Information Management thesis, I thought it would be interesting to analyse my final thesis references to find out how many journal articles about open access (OA) were paywalled. A paywalled journal article is where there is a cost to read the article, either via a one-off payment or a subscription (for example through a university library). The alternative to paywalls is open access, where research is free for all to read. Some journals are free for authors to publish as OA, and some journals require payment to publish as OA.

Now that I’ve submitted my thesis, I have more time to answer my questions about my thesis literature review:

Q1. What percentage of journal articles about OA were paywalled?
Q2. How much it would cost me to access these paywalled articles if I wasn’t a Curtin University student?
Q3. For the OA articles that required payment, how much did they cost?
Q4. For the paywalled articles, what rules did the journal have about OA? Is it possible that some of these paywalled articles could become OA?


I used the following steps to turn a list of references in a Word document into an OA status spreadsheet:

Extract journal article URLs from Word document

My thesis references contained 90 journal articles, webpages, grey literature and books (thanks free Zotero for painless reference formatting). 29 of these references were journal articles about open access and institutional repositories (digital archives used to preserve an institution’s research outputs, usually publicly accessible as a website). In exchange for a cup of tea, my software developer husband automagically extracted URLs from the References section of my thesis. After pasting the references into vim, he used the following commands to extract the URLs:

this command deletes all lines with no ‘http’


this replaces a whole line with just the URL


Run the URLs through Unpaywall’s Simple Query Tool

I ran the resulting text file through Unpaywall’s free Simple Query Tool which checks DOIs and returns a spreadsheet (or .csv or JSON) showing if the DOIs are OA or paywalled (closed). A DOI or Digital Object Identifier is ‘a unique, permanent identification number that will take you straight to a document no matter where it is located on the Internet’ (Victoria University, 2021). 

Unpaywall’s Simple Query Tool also returns (among other fields) whether the DOIs are green, gold, bronze, hybrid or closed where:

‘Gold: Published in an open-access journal that is indexed by the DOAJ.

Green: Toll-access on the publisher page, but there is a free copy in an OA repository.

Hybrid: Free under an open license in a toll-access journal.

Bronze: Free to read on the publisher page, but without a clearly identifiable license.

Closed: All other articles.’ (Piwowar et al., 2018, p. 5)

Manually check any URLs that are not DOIs

Some journals use URLs rather than DOIs, and Unpaywall can only check DOIs. I manually checked one URL to see if it was OA or paywalled. 

The resulting spreadsheet contained 29 journal articles, with their OA status and type. For the articles that Unpaywall reported were closed (paywalled and not OA), I opened them in an incognito Chrome tab to confirm. The reason for using an incognito tab was to make sure my Curtin University student credentials were not being used to give me access to full articles. 


Q1. What percentage of journal articles about open access were paywalled?

Almost a quarter (7) of the 29 journal articles I cited about open access were paywalled.

Pie chart with heading 'Paywalled vs open access'. A red section reads 'paywalled 24% (7 articles). A blue section reads 'open access 76% (22 articles).
Numbers of paywalled and OA articles (total = 29 articles)

Open access has lots of different types, and as mentioned above Unpaywall’s Simple Query Tool returns the OA types in its results. Note that some of the articles that are now green OA may have previously shown up as paywalled because publisher embargoes delaying OA publication were still in effect. For more discussion of OA types, read Aaron Tay’s blog post on this topic.  

Here’s the breakdown for this sample using Unpaywall’s OA types (listed above in the Method section). For each OA type, the number of articles and percentage of total journal articles (29 articles) is included.

Pie chart with heading 'Open access type breakdown'. Sections are:
red 'closed 24% (7 articles);
green 14% (4 articles);
gold 38% (11 articles); bronze (3 articles); hybrid 14% (4 articles).
Numbers of OA articles by type (total = 29 articles)

Q2. How much it would cost me to access these paywalled articles if I wasn’t a Curtin University student?

For the closed journal articles, I looked up the current cost to buy the closed articles on journal publisher websites. If I didn’t have access via Curtin University Library subscriptions, the approximate cost to read all 7 paywalled articles would be approx. $365 AUD ($280 US).

Q3. For the OA articles that required payment, how much did they cost?

For the journal articles that were OA but had a cost to publish, I looked up the current Article Processing Charges (APC). Where a publisher website did not specify a currency, I assumed USD.

The total cost to publish 9 articles was approx. $29,200 AUD ($22,600 USD), and this money went to the journal publishers. The authors may have been able to pay these APCs with funding from their research grant, or support from their institution. Keep in mind that the true cost of publishing for the authors who paid may have been lower due to factors such as: transformative agreements; discounts and waivers dependent on the country of the corresponding author; and institutional and society discounts.

A system where the author pays the publisher an APC to make research available to all sounds better than paywalls. However, consider researchers in developing countries who cannot afford these costs, even with APC waivers in place.

Q4. For the paywalled articles, what rules did the journal have about OA? Is it possible that some of these paywalled articles could become OA?

My next question was could any of the paywalled articles be available as OA in any way, for example adding a pre-print to an institutional repository. Some researchers are unaware of a website called Sherpa Romeo, where you can check what rules publishers have about sharing publications as OA.

Using Sherpa Romeo, I checked the OA rules for the journals of the 7 paywalled articles. Almost all journals allowed green OA (some with embargoes which have passed). The exception was one journal which only allows green OA for specific funders after a 12 month embargo. This suggests at least three reasons why these paywalled articles are not available as green OA:

  • that the authors of the paywalled articles didn’t get around to sharing them as green OA via institutional repositories or personal websites
  • when the article was published the publisher did not allow green OA
  • Unpaywall couldn’t find a green OA copy but it exists somewhere.


Many OA researchers work within library and information science as part of a humanities faculty, therefore reasons given by humanities researchers for not publishing OA are relevant. These reasons are summarised in Arthur et al. (2021, p. 11). Looking at these reasons in the context of articles written about OA, we can probably assume that the authors understand OA concepts and the importance of institutional repositories. Therefore, some of the remaining reasons applicable for not publishing articles about OA as open access are:

  • a dependency on prestigious journals for career progression (Arthur et al., 2021, pp. 11-12)
  • not having access to funds to pay APCs (Tenopir et al., 2017, p. 839). 


Writing this blog post satisfied a curiosity to find out how many journal articles in my thesis references about open access were paywalled. Piwowar et al. predict that by 2025, ‘44% of all journal articles will be available as OA’ (2019, p1). Compared to this estimate, the result in this small sample that 76% of journal articles are available as OA is positive (or 24% paywalled). However, the situation where some readers have to pay for an article about open access shows just how broken the academic journal publishing system is.    

Learn more

Read more about OA

If you have time for a documentary, watch for free ‘Paywall: The Business of Scholarship’


Arthur, P. L., Hearn, L., Montgomery, L., Craig, H., Arbuckle, A., & Siemens, R. (2021). Open scholarship in Australia: A review of needs, barriers, and opportunities. In Digital Scholarship in the Humanities. (read the free pre-print at

Piwowar, H., Priem, J., Larivière, V., Alperin, J. P., Matthias, L., Norlander, B., Farley, A., West, J., & Haustein, S. (2018). The state of OA: A large-scale analysis of the prevalence and impact of open access articles. PeerJ, 6, 1–23.

Piwowar, H., Priem, J., & Orr, R. (2019). The future of OA: A large-scale analysis projecting open access publication and readership. BioRxiv, 795310.

Tenopir, C., Dalton, E. D., Christian, L., Jones, M. K., McCabe, M., Smith, M., & Fish, A. (2017). Imagining a gold open access future: Attitudes, behaviors, and funding scenarios among authors of academic scholarship. College & Research Libraries, 78(6), 824–843.

Victoria University. (2021). Library guides: APA 7th referencing.

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