The ICSP and the Microbiology Society’s appeal to Clarivate regarding suppression of the IJSEM from the 2019 Impact Factor

Update: 28 July 2020

The ICSP and the Microbiology Society are pleased to announce that our appeal against Clarivate's decision to suppress the journal from the 2019 Journal Citation Reports has been successful. International Journal of Systematic and Evolutionary Microbiology will be reinstated in the 2019 Journal Citation Reports (JCR). The journal's metrics can be found on our Article and journal metrics page.

Our appeal

ICSP and the Microbiology Society are appealing Clarivate's decision to suppress International Journal of Systematic and Evolutionary Microbiology from the 2109 Journal Citation Reports. As transparent organisations we believe it is in the interests of the microbiology community for the text of the appeal to be made available, and it is therefore replicated here:

Dear [redacted],

To follow up on our previous conversations, I write regarding the suppression of International Journal of Systematic and Evolutionary Microbiology (IJSEM; eISSN 1466-5034) from the 2019 Journal Citation Reports, outlining why we believe the suppression to be unreasonable and to request Clarivate reinstate IJSEM in the JCR as a matter of urgency. Please note that at the request of the Editorial Board, and in line with the Microbiology Society's values, we will be posting this appeal to our website. 


IJSEM is owned by the International Committee on Systematics of Prokaryotes (ICSP), and is the official journal of both ICSP and the Bacteriology and the Applied Microbiology Division of the International Union of Microbiological Societies. To comply with the International Code of Nomenclature of Prokaryotes, ICSP requires that new bacterial names are published in IJSEM and nowhere else – something which is appreciated by the microbial systematics community as a benefit, particularly when compared with the far less codified mechanism for naming new viral taxa. In 2017 and 2018 articles describing new taxa made up 91% of published content in IJSEM. In highlighting these article types, we must add that the taxa described in such articles are frequently rare, have not been previously described, and may well be unique to a specific time or place (that is, they may not be seen again). In addition to these articles, IJSEM also publishes proposed changes, such as reclassifications of strains into new or different groups, which inform future iterations of the International Code of Nomenclature of Prokaryotes as well as future research that may well be published in the journal. 

Citations to IJSEM

As the premier venue for publishing microbial taxonomy, it must be clear to you that many articles published in IJSEM will have to cite articles previously published in the journal: there is no other publication source for this work. 

While IJSEM serves the wider microbiological community and in theory all references to the strains validly published in IJSEM should be cited by researchers working on those strains, there is a very peculiar convention among microbiologists who are not taxonomists which leads them not to cite the taxonomic papers in which their research subject was first described. This convention means that, despite taxonomy being critical to the discipline of microbiology, few articles in other journals will cite taxonomic papers. The primary audience of IJSEM is thus taxonomists, and these are the researchers citing IJSEM. This means taxonomic papers are heavily cited in major reference works such as Bergey’s Manual of Systematics of Archaea and Bacteria (BMSAB, described below). The exclusion of citations from Bergey’s to IJSEM in 2019 has artificially raised the self-citation rate in your dataset. The inclusion of Bergey’s, among other sources, in other datasets has resulted in the self-citation rate for IJSEM in 2019 falling to less than 35% from a peak of over 40% (Figure 1). As both Scopus and the Leiden University CWTS database release their data earlier than the JCR, we had no reason to suspect levels of self-citation at the rate you claim.

Figure 1. Self-citation rates in IJSEM, 1999–2019.

Having said this, we did identify eight of the 817 groups who published with IJSEM in 2019, that had been artificially inflating their own citation rates via 'salami slicing'. Despite this representing only 1% of publications in IJSEM, we have already put measures in place to prevent such activity and have applied those measures across the Microbiology Society portfolio. In fact, the current and previous Editors-in-Chief of IJSEM published an editorial calling on authors to avoid salami slicing in early 2018 (https://doi.org/10.1099/ijsem.0.002634) and early interventions to reduce such minimal publications were introduced then. 

Ethical considerations

Many microbial taxonomists are from countries which prohibit publication in journals which do not have a Journal Impact Factor, such as the Republic of Korea (107 corresponding authors in 2019). In the week since the JCR was released we have already received emails stating that researchers in Korean institutions are not permitted to submit future work to IJSEM, or that such work will not be considered when researchers apply for grants or roles. It is not our Korean authors alone who are concerned: a large proportion of articles published in IJSEM are from author groups in low and low-middle income countries, or countries where the Journal Impact Factor is still a primary driver of funding and promotion, and it is these authors who are fundamentally disadvantaged by your decision. 

In a time of global awareness of the dangers posed by microorganisms, we must also draw your attention to a letter from one of our Editorial Board members, who writes:

“For decades, we have been isolating new bacterial species from human specimens, either as pathogens or commensals. To date, we have described more than 700 new species. As a medical doctor, it is crucial for me to report the discovery and description of these species in order to allow other physicians to identify correctly these microorganisms when they face them, and thus treat their patients appropriately. As the official journal of the International Committee for the Systematics of Prokaryotes, IJSEM plays an essential role in keeping scientists updated on new species. Removing the Impact Factor of this well respected journal with a high standard of taxonomic descriptions will create confusion, as in some countries (China notably), it is requested to publish in journals with an Impact Factor only. The risk of the present situation is that scientists from these countries will no longer submit their articles to IJSEM and the quality of taxonomic descriptions may decrease, with a direct impact on patient management.”

Subject-matter expertise

Clarivate has long claimed that the JCR is supported by subject-matter expertise on the part of the editorial team. The suppression in 2019 of two journals of systematics, in the form of IJSEM and Zootaxa (eISSN 1175-5334), suggests a lack of understanding on the part of the Clarivate team of the nature of systematics and taxonomy. We know that many of the Zootaxa community share our opinion, as for example the letter from the President of the International Society of Arachnology shared on Twitter (https://twitter.com/ISArachnology/status/1279099807068352512). 

Your email claimed that suppression is based on self-citation rates deviating from the norm for a particular category – in the case of IJSEM, Microbiology. One must wonder whether establishing a category for systematics and taxonomy might be a satisfactory solution, and better reflect the unique nature and importance of these titles to their communities.

To summarise

International Journal of Systematic and Evolutionary Microbiology is the official journal of record for prokaryotic names and serves a highly valuable role within the microbiological community by validating newly discovered taxa. As no other journal will publish such material, the small community of taxonomists who produce the articles published in IJSEM cite similar strains that were previously published in the journal, leading to self-citation. 

I look forward to hearing from you soon,

Best wishes,

Tasha Mellins-Cohen

Director of Technology and Innovation, Microbiology Society.

Supporting information about Bergey's Manual of Systematics of Archaea and Bacteria (BMSAB)

Since its formation in 1936, Bergey's Manual Trust has provided comprehensive and authoritative descriptions of bacteria and archaea through the publication of its Manuals on Systematic Bacteriology. The result of a collaboration between the Trust and nearly 1000 microbiologists from all over the world, the Manual provides extensive descriptive information of the taxonomy, systematics, physiology, ecology and habitats of individual prokaryotic groups as well as a natural classification of prokaryotes that reflects their evolutionary history.

About 100 new genera and 600+ new species have been described per year for each of the last 5 years. To remain abreast of this explosion in knowledge of the microbial world, an electronic manual with frequent updates is necessary. The BMSAB is an essential tool for anyone at the forefront of research in microbiology.

Bergey's is the most complete and authoritative description of bacterial and archaeal diversity.

BMSAB is managed by Bergey’s Manual Trust, a nonprofit organization and its income is used solely for the purpose of preparing, editing and publishing revisions and successive editions of the Manual and any supplementary publications, as well as providing for any research that may be necessary or desirable in such activities.


1. Background

Impact Factors are released annually by Clarivate through the Journal Citation Reports and are important to many researchers, including our members and authors. Clarivate have decided not to give a 2019 Impact Factor to International Journal of Systematic and Evolutionary Microbiology (IJSEM).

2. FAQs

Why has IJSEM not been given a 2019 Impact Factor?

On 19 June 2020, Clarivate contacted the Society stating that IJSEM “will not be included in the upcoming release of the Web of Science Journal Citation Reports (JCR) from Clarivate due to atypically high levels of journal self-citation.” They added that their analysis of 2019 citation data for the journal showed: “56.6% of all 2019 outgoing citations from the journal to 2018 or 2017 scholarly literature were journal self-citations. These citations account for 40.7% of the JIF numerator.” Clarivate have been very clear that IJSEM is not suspected of any misconduct, simply that it is an outlier in citation behaviour within the Ecology, Evolution, Behavior and Systematics category of the JCR.

Is the claim that IJSEM has very high self-citation true?

No. The Society team have investigated Clarivate’s claims and cannot find any evidence to support the assertion that 56.6% of 2019 citations were self-citations. For example,

  • Data from Scopus [1] showed that 1838 of 5514 citations in 2019 were self-citations (33.3%), continuing a five-year trend towards decreasing self-citation.
  • Data from the CWTS Journal Indicators database from Leiden University [2] put 2019 self-citations at 34.5%, again in line with a continuing downward trend.

Data from other sources, including Crossref and Google Scholar, are in line with that provided by Scopus and Leiden University.

What is the Society doing to get a 2019 Impact Factor for IJSEM?

On 19 June 2020, Clarivate contacted the Society to inform us that IJSEM was not being awarded a 2019 Impact Factor. We immediately responded to the message to ask for an explanation, and to request that Clarivate share their data to allow us to properly investigate their claim. In that message we reminded Clarivate of the unique nature of IJSEM as the only journal publishing bacterial taxonomy, which naturally limits the range of sources that authors are able to cite, and presented them with publicly-available information about self-citation rates that does not tally with their assertions.

Clarivate acknowledged receipt of our emails on 25 June 2020, and on 3 July indicated that they would be open to an appeal (detailed above). We are maintaining open lines of communication and will update these FAQs as more information becomes available.

What should the 2019 Impact Factor for IJSEM be?

Scopus provides a metric called ‘citations per document’, which counts the number of citations received by documents (articles) from a journal in a year, and divides them by the total number of documents published in that journal in the past two years. This is the Scopus equivalent of an Impact Factor. For 2019, Scopus reported that the 2-year citations per document score was 2.53, increasing from 2.26 in 2018. This puts IJSEM in the top quartile for the Ecology, Evolution, Behavior and Systematics category, and the second quartile for the Microbiology category.

The CWTS Journal Indicators database from Leiden University also provides a metrics comparable with the Impact Factor, called Impact Per Publication (IPP), calculated as the number of citations given in the present year to publications in the past three years divided by the total number of publications in the past three years. For IJSEM, the 2019 IPP was 2.27, up from 1.98 in 2018.

The Society is a signatory to DORA, the Declaration on Research Assessment, why does it care about Impact Factors?

We are indeed DORA signatories, which means we believe that research should be judged on its own merit and not on the basis of where it is published. Similarly, one of our key values is transparency and the Impact Factor calculation is shrouded in secrecy. We are, however, appealing against Clarivate’s decision for two reasons: first, because we know that many of our members and authors care deeply about Impact Factors and similar metrics; and second because we believe the decision, which could have significant implications for a journal critical to the community, is based on incorrect data and a misunderstanding of the nature of the journal, and thus unreasonable.

What does this mean for my article published in IJSEM?

The Society has displayed article-level metrics for all articles published on microbiologyresearch.org for many years. In 2020, we added Altmetric attention scores and Dimensions citation information to all articles, including those in IJSEM. This means you can see how frequently your article has been cited, based on openly available information, as well as social media mentions and downloads of the full-text of the article, on the article homepage. These article-level metrics are produced by third parties who are independent of both the Microbiology Society and Clarivate.  

Can I still submit articles for peer review and publication in IJSEM?

IJSEM remains the journal of record for publication of novel microbial taxa and the official publication of the International Committee on Systematics of Prokaryotes and the Bacteriology and Applied Microbiology Division of the International Union of Microbiological Societies, and it is still open for submissions.

What about the Society’s other journals?

None of the Society’s other titles are affected, and they received Impact Factors as usual when the 2019 Journal Citation Reports were released. You can find their Impact Factors, alongside other article- and journal-level metrics, here.  

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