The impact of the open-access status on journal indices: a review of medical journals

Introduction

Open access (OA) journals allow free (access to/availability of) academic articles, they enable any user to read, search, download, share, use them for indexing, print the full texts, or utilize them as data for software without being charged¹. Over the past 20 years, there has been an increase in the number of OA medical journals. According to Web of Science, published OA articles as a proportion of total publications increased from 9.5% to 24% from 1998 to 2018. These OA journals provide an easily accessed source of information, a source that is accessible even for developing and low income countries².

Bibliometric analysis are methods or applications used to measure the influence of authors or scientific papers, of which, citation analysis is the most commonly used methods³. Now several citation databases have become available, with the three largest being Web of Science, Scopus and PubMed. These databases record the number of times that a journal article has been cited by other papers⁴. The use of bibliometric analysis is becoming more popular to assess the performance of different aspects of the scholarly and scientific fields. Analysis can be at the level of the researchers themselves, journals, departments, universities, national organizations, and even entire nations^5–8. There are several databases that can be used to perform the bibliometric analysis, with each database having its own characteristics; these include Google Scholar, Pubmed (Only biomedical citations), Scopus, and Web of Science⁴. According to the number, coverage, and quality of citations covered by the databases, Scopus has wide coverage of high quality journals, compared to high number of citations at the expense of quality for Google Scholar, and high quality at the expense of number of citations for Web of Science^9–11.

It is claimed that the emergence of OA journals has led to better dissemination of knowledge with the additional benefit of more citations for the authors, although this is still a matter of debate¹². In this study, we aim to study the OA status of medical journals and the impact of the open-access status on journal indices using the Scopus database.

Methods

Results

In the 2017 Scopus list of journals, there was 5835 medical journals. Regarding the 5 most common publishers, 890 (15.3%) journals were from Elsevier, 653 (11.2%) Springer Nature, 196 (6.8%) Taylor & Francis, 360 (6.2%) Wiley-Blackwell, and 304 (5.2%) Wolters Kluwer. 1293 (22.2%) journals were OA journals. Table 1 indicates the minimum, maximum, mean, and standard deviation of medical journal indices.

Upon analyzing the difference between medical OA and non-OA journals, we found significant differences in the following indices:

Upon comparing open access journals between the 5 most common publishers, we found a significant difference (p< 0.001). Post-hoc analysis showed that Wiley-Blackwell has significantly lower number of open access journals 16 (4.4%) open access journals compared to others. Table 2 shows the open access status for the most common publishers.

Discussion

Our study found that OA medical journals had significantly higher CiteScores, Percent cited and SNIP; which is consistent with a number of previous studies made across a variety of disciplines including philosophy, political science, engineering, mathematics, physics, computer science and agriculture; all of which concluded that open access publications have a greater research impact (higher citation rate) than non-open access publications^12,14–16. On the other hand, in a randomized controlled trial conducted on 11 biological and medical journals, it was found that only 2 of these journals showed positive and significant OA effects. In addition, it was found that OA advantage is declining by about 7% per year, from 32% in 2004 to 11% in 2007¹⁷. Chua et al. found that there was significantly more citations in OA articles than in non-OA articles within almost identical journals’ impact factor¹⁸. Moreover, comparing citations in OA and non-OA articles in the same journal showed significant citation privilege for OA publications in several studies. For example, for the Journal of Postgraduate Medicine a comparison of citations per 100 articles per year before and after the journal became open access showed an increase between 3 and 4.5 times in citations¹⁹. In a longitudinal study of a cohort of OA and non-OA articles, it was shown that OA articles are cited earlier, and almost 2 times more frequently than non-OA articles in the first 4–16 months after publication in the same journal²⁰. Regardless of all the aforementioned findings, our study found that non-OA medical journals have significantly higher Scholarly Output which can be strongly linked to the fact that most non-OA medical journals have been established years before OA journals, which have only recently emerged²¹.

We found that the number of OA journals varied among publishers, with Whiley-Blackwell having the least, with only 16 journals (4.4%), and the most with Springer Nature (206, 31.5%). In a previous study that analyzed OA articles published by different publishers, regardless of the discipline, they found that Elsevier had the highest number of OA articles, followed by Springer Nature and Whiley-Blackwell²². A longitudinal study comparing hybrid open access articles between publishers found great variation depending on the discipline²³. For instance, medicine is the discipline which most frequently publishes in hybrid OA²³.

Our study has potential limitations. In this study, we didn’t account for the effect of publishing OA articles in non-OA journals (hybrid journals), as “Gold” OA publishing (i.e. fully OA journals) relates to publication of articles that are freely available to view and these may occur in OA or hybrid journals. Moreover, future studies should consider analyzing specialties within medicine (e.g. oncology), where we believe there will be variations in the effect of OA publishing within these specialties.

Data availability