When Scientists Pay to Unlock Their Research: Does Free Access Mean More Readers?

The problem:

It is a golden age for science. Researchers are connected all over the world, and the ease of sharing information nowadays allows knowledge to spread quickly and easily. Because we are so well-connected, scientists can concentrate on conducting research, and our globalized websites, platforms, and networks take care of everything else. Right?

Unfortunately, it is not so easy. To understand why, we have to take a closer look at how science is shared. New studies are published in scientific journals, which may still be printed, but mainly run through their websites where people can download whole issues or single articles. Different journals focus on different areas of science. But depending on the way a journal chooses to share its articles and make money (the publishing model), studies (controversially many of which are funded with taxpayer money) may be hidden behind a paywall. In that case, only those with a subscription to the journal or who pay for individual access can read the study.

Scientists are interested in making their work accessible to everyone. This allows their work to be recognised, built upon, and absorbed into a bigger body of knowledge. The number of times other researchers refer to their work by citing it in their papers is often understood as a way of measuring impact and success. To maximise this and make sure that their work will not end up behind a paywall, scientists can pay money to publishing journals to make their research ‘open access’. This is often very expensive and can cost up to 5000 US dollars for a single article.
There are different kinds of open access:

In gold open access, articles are free to read right away. Some journals only contain these freely accessible studies paid for by the authors. Hybrid journals have most articles behind a paywall, but authors can pay a fee to make theirs free.

Bronze open access means journals themselves choose to make some articles free, though this may only be temporary.

Green open access is when authors share their own copy, such as a preprint or a version stored in a university archive; this option is usually free but sometimes has restrictions or time delays.

But does paying for gold open access actually deliver what scientists hope for? If they spend the money, does it really make their work more visible and more cited?

The approach of the study:

To answer this question, the lead authors Amanda Clark and Tanner Myers and their team looked at over 146,000 studies from journals covering multiple areas of biology, such as Zoology, Cell Biology, and more.

The researchers wanted to see if free-to-read articles got more citations, while also checking other things that might influence the results. Because citation numbers are very uneven (some articles get thousands, many get few), they used a special kind of maths model, which works well for rather messy data. Then they ran statistical analyses to answer their questions.

First, they looked at all articles to see if they were open access. They noted down author count, journal popularity, and year to find possible explanations for differences in citations.

Second, they only looked at journals that had both open access publications and articles behind paywalls. This allowed them to compare studies from the same journal and ensured that journal popularity did not skew their results. This is because we know that journal popularity itself influences how much attention a study gets.

Third, they looked only at open access articles to test whether the amount of money paid (the so-called Article Processing Charge or APC fee) was linked to how many times the article was cited.

For their work they used so-called “generalized linear models”. This is a maths tool that can test how one factor (like being free to read) affects the results (citation count) while keeping the influence of other factors (APC cost, number of authors) checked. All the analyses were run in the R computer program, which is often used by researchers.

Key findings:

What did the researchers find? At first glance, paying seemed to increase citations as open-access studies had an average of 31.1 citations. Paywalled studies had an average of only 19.3 citations.

However, there were two things that influenced the findings: Number of co-authors and cost.

So, how did the number of co-authors influence the citation number?

The number of authors on a study made a big difference. For studies with only one author, paying to make the study open-access (gold open access) seemed to pay off more: these studies received almost three times as many citations when compared to articles behind paywalls. They had more citations than articles the journals themselves made freely accessible (bronze open access). They also had an advantage over articles published in free journals or on free websites (green open access).

For studies with multiple authors, however, the picture was a different one. The more authors on a study, the smaller the advantage in citation numbers became. If a study had over 16 authors, it no longer mattered for citations whether it was published as open-access or behind a paywall.
Did paying a higher price for gold open access also increase citation number?

The second big factor influencing citation count initially seemed to be cost; the study showed that the more it cost to make an article open access, the more citations it got. But this may be easily explained: the more popular a journal, the more money they feel they are able to charge. When the researchers took this into account, they no longer saw this effect – it was the popularity of the journal that mattered, not the cost of publishing open-access itself.

Interestingly, publishing research in free journals or on free websites, also led to a slight increase in citation number over paywalled publications, although the effect was smaller. Therefore, simply paying a higher fee did not lead to more citations.

How good was the study?

This study has some strong points. First, it looked at a really big set of data – over 146,000 articles from 152 different biology journals. The researchers didn’t just compare across different journals but also looked at articles in the very same journal and even the same issue, which makes the test fairer. They checked the question from several angles, using three types of analysis, and used good maths tools that can handle messy data. They also gave practical tips to help scientists decide if paying for open access is worth it.

But the study also has some limits. It only included a selected group of 152 biology journals, so it doesn’t show the full picture for all journals or for other fields. The prices of open access fees they used were from 2021, not the actual prices authors paid back in 2013–2018, when the papers they looked at during the study were actually published.

It was also hard to know exactly when some articles became free or for how long due to different kinds of open access models (if you want to find out more, browse online to understand the differences between the different options, for example ‘bronze’ compared to ‘green’ open access). This could change the results. And for papers with very large teams of authors, the advantage of open access was smaller or sometimes not there at all. The researchers don’t offer a concrete reason for this, but one possible interpretation (based on citation studies) is that big-team papers already get wide attention because of their networks, so being open access doesn’t add much extra visibility compared to smaller-team papers.

Why does this matter?

So, what does this all mean? If you are a scientist and want to make sure that many people see and cite your research, you might be considering paying a journal a lot of money so that everyone can easily access your article. But not all researchers have the funding to do this- so, are researchers in low-income countries or with small or no funding automatically at a disadvantage?

This research shows that paying to make an article open access was usually linked to more citations, with the biggest advantage seen in studies with only a few authors. For papers with many authors, the effect was much smaller, likely because large teams already spread their work widely. Still, the results need careful interpretation: authors may be more likely to pay for open access when they think a paper is especially important. If that is true, then some of the citation advantage comes from the paper’s quality or significance, not just from being open access, so the effect may be smaller than it first appears.

The study authors recommend choosing the journal that best fits your research, whether or not you decide to pay for open access. Many journals also let you self-archive your article for free after 6 months to 2 years (this is called an ‘embargo’). You can self-archive on institutional repositories, which are universities’ online libraries of research, or on preprint servers, which are public websites for early versions of papers. This brings you a small citation boost but, most importantly, it helps make science accessible to everyone.