Viewpoint
March 20, 2023
The Rapid Growth of Mega-Journals: Threats and Opportunities
John P. A. Ioannidis, Angelo Maria Pezzullo, Stefania Boccia
JAMA. Published online March 20, 2023. doi:10.1001/jama.2023.3212
Mega-journals, those that publish large numbers of articles per year,1 are growing rapidly across science and especially in biomedicine. Although 11 Scopus-indexed journals published more than 2000 biomedical full papers (articles or reviews) in 2015 and accounted for 6% of that year’s literature, in 2022 there were 55 journals publishing more than 2000 full articles, totaling more than 300 000 articles (almost a quarter of the biomedical literature that year). In 2015, 2 biomedical research journals (PLoS One and Scientific Reports) published more than 3500 full articles. In 2022, there were 26 such prolific journals (Table). The accelerating growth of mega-journals creates both threats and opportunities for biomedical science.
Several criteria have been proposed to define mega-journals, but not all mega-journals fulfill all criteria.1-3 Here, for operational purposes, we define mega-journals as open-access peer-reviewed journals that charge article processing fees and publish more than 2000 full articles in a calendar year. The 2 early-launched mega-journals, PLoS One and Scientific Reports, were also characterized by very broad publishing scope, covering scientific topics in general. Most mega-journals in 2022 seem to have had more focused publishing objectives (eTable in the Supplement). Moreover, issues that cover specialized topics are very popular,4 recruiting tens of thousands of guest editors and attracting hundreds of thousands of authors. Guest editors may vary in competence and level of involvement, which may contribute to a more disorganized, inconsistent author experience from article to article.
Mega-journals maintain respectable journal impact factors that make them attractive to authors seeking to place their work (Table). Some mega-journals have high self-citation rates, but not high enough to get them into trouble (eTable in the Supplement). One of the earliest specialized mega-journals, Oncotarget, grew rapidly to the point of publishing 10 336 items in a single year (2017) at its peak; then Clarivate delisted it from Journal Citation Reports under contested circumstances.5 Without an impact factor, its output decreased to a mere 159 articles published in 2022.
Mega-journals typically claim to publish articles based on whether they are scientifically sound rather than important and novel. Accordingly, their acceptance rates, when disclosed, are 20% to 70% (eTable in the Supplement). Although mega-journals promise rapid peer review, disclosed average review times are not necessarily short (eTable in the Supplement). Many higher-impact journals have faster turnaround.
The rise of mega-journals has coincided with a similar rise in preprints in biomedicine. Preprint servers only screen articles before posting them rather than conduct detailed review, and their acceptance rates are typically greater than 70%. The revenue model of mega-journals is based entirely on charging article publication fees. The publishers increase these fees when a journal improves its impact factor ranking. The model secures high journal revenue but poses difficulties for authors with limited discretionary funds.
The growth of discipline-specific mega-journals testifies to the large demand for publishing scientific articles in journals with high enough impact factors despite efforts like that of the Declaration on Research Assessment (DORA) to dismantle attention to impact factor.6 In this vein, mega-journals may perpetuate and accentuate an already dysfunctional system of scientific evaluation and publication. Moreover, perhaps some authors do not find peer review helpful and are looking for easiest paths for publishing, or they conduct trivial research that, regardless of its results, would never compete in the highest-impact journals.
It would be unfair, nevertheless, to dismiss mega-journals as simply a negative development. Several of their characteristics could be aligned also with desirable scientific practices. First, open access is a good starting point, and it can be coupled with greater transparency. If these journals routinely adopt transparent research practices, such as sharing of data, code, protocols, and statistical analysis plans, they can have a transformative effect, given their large output. Several older, broad-scope mega-journals (eg, PLoS One, Royal Society Open Science) have already championed such efforts. It is crucial that disciplinary-focused mega-journals do the same. Second, publishing technically sound scientific work regardless of the nature of the results is highly commendable. It offers opportunities to curb publication and selective reporting bias. Empirical studies are needed to investigate whether mega-journals do achieve this goal or still have selective reporting biases and variants thereof (eg, “spin”). Third, mega-journals may allow publication of results deemed undesirable in traditional specialty journals with entrenched, inbred publishing practices. Enhanced diversity of perspectives and opportunities to challenge orthodoxy are welcome, provided the journals publish rigorous data and safeguard against conflicts of interest. Securing editorial independence and maximizing transparency about conflicts for editors, reviewers, and authors will be key in reaping such benefits.
More important, mega-journals may change medical and scientific publishing at large through indirect effects on other journals. Mega-journals create journal- and publisher-level competition. Broad-scope mega-journals such as PLoS One and Scientific Reports never seriously threatened traditional specialty journals7: the latter continued to dominate their specialized niches in both volume and influence. Conversely, some discipline-focused (specialty) mega-journals already publish more articles than all the classic journals in the same field combined. Coupled with lucrative impact factors, their competition may be transformative or lethal for traditional, respectable journals. For example, in 2022 the International Journal of Environmental Research and Public Health (impact factor of 4.614) published 16 889 full articles (original articles or reviews) and Frontiers in Public Health (impact factor of 6.461) published 5043 full articles, whereas the American Journal of Public Health, European Journal of Public Health, American Journal of Epidemiology, and Epidemiology published only 514, 238, 222, and 101 full articles, respectively.
Competition may also arise regarding rapid publication. Some mega-journals adopt policies to facilitate a rapid review process; for example, reviewers who provide timely peer-review reports receive vouchers entitling them to a discount on their next publication (eTable in the Supplement). Empirical studies are needed to compare the rigor of the peer-review process by traditional journals vs mega-journals. This will require making peer reviews available for content analysis. Mega-journals may drain an already strained pool of reviewers from traditional journals.
At the publisher level, competition may have major indirect effects on medicine and science at large. Scientific publishing has an annual work cycle exceeding $30 billion and very large profit margins, which are possible in part because approximately 100 million hours of peer reviewers’ time is offered free yearly.8 The publishers behind the new generation of specialized mega-journals (Table) are taking this money-making recipe to new heights. Science and scientists may feel thwarted, if not entirely powerless, while big publishing corporations fight for field domination. However, it would be to the benefit of all if scientists, medical and research institutions, and funders gave credit to and rewarded journals (and publishers) that promote more transparent research and more rigorous research practices. Scientists could prioritize submitting to and citing work from these journals, and institutions and funders might offer incentives for preferring publication in these venues. Moreover, journals that do not depend on commercial publishers and have more secure finances (eg, large general medical journals published by medical associations, such as JAMA and BMJ) could lead in raising the standards of transparency and rigor and in spearheading new initiatives therein. They could offer paradigms to also steer the journals that publish the bulk of the literature.
The explosive growth of mega-journals may be accompanied by the fall of some previously prestigious journals. Journals are not permanent: of 27 general medical journals publishing in 1959, only 6 published continuously with the same name until 2009.9 The half-lives of scientific journals may be shortened in the current shifting environment. What matters is whether journals that publish the lion’s share of the literature endorse and facilitate the best research practices.
