Journal Citation Reports editorial expression of concern

Our suppression principles

At Clarivate, we believe in the importance of maintaining the integrity of the scientific record. We apply rigorous selection criteria for the inclusion of content in our databases. As a responsible bibliometrics provider, we also monitor, survey and curate our data to identify anomalies that lead to distorted metrics and rankings. We have no doubt that distortion of citations is harmful as it creates an inaccurate reflection of the connections between articles and their contribution to the scholarly network.

We realize that suppression of a journal from the Web of Science Journal Citation Reports™ (JCR) affects publishers, authors, editors and peer reviewers; we do not take this action lightly. The importance of our data and metrics to the research and publishing communities means we have a particular and extraordinary responsibility to interrogate, curate and edit these data ourselves. We review the citation patterns to ensure that our data is as accurate as it can be, but we do not assume motive on behalf of any party. Read more about our suppression principles.

2020 Summary

While researching data relevant to journal self-citations, we detected instances of unusual article citation behavior.

The titles below contain journal self-citations that are highly concentrated to the Journal Impact Factor™ numerator. They had one or more published items with an atypically large contribution of journal self-citations. These citations were disproportionately concentrated into the JIF numerator.

The data that have raised this concern are fully transparent to all JCR users through the “Journal Impact Factor Contributing Items” in the “Citations in 2019” tab.

The titles listed represent extreme examples. As part of our commitment to data transparency and responsible metrics, we will continue to review content of this type in order to develop additional screening for distortions of the citation network and the JIF.


Journal Title
JIF numerator
single- paper journal
Total journal self-citations
Annals of Allergy Asthma & Immunology




Applied Surface Science




Arteriosclerosis Thrombosis and Vascular Biology




Artificial Organs

707 155


British Journal of Biomedical Science

198 52


Cardiovascular Research




International Archives of Allergy and Immunology




Journal of Allergy and Clinical Immunology-In Practice




Journal of Cardiovascular Magnetic Resonance




Journal of Cleaner Production




JACC-Cardiovascular Imaging




Minerva Anestesiologica








Sociology of Sport Journal




Structural Chemistry






2019 Summary

Our team has conducted a detailed review of the 2015-2019 content, citations, authorships and editorial membership of the five journals named in our 2018 Editorial Expression of Concern (below). We found a pattern of highly concentrated referencing among four journals:  Nanoscience and Nanotechnology Letters, Journal of Biobased Materials and Bioenergy, Journal of Biomedical Nanotechnology, and Journal of Nanoscience and Nanotechnology, and including citations to a fifth journal  Bone Research.  The result of these citations was a distortion of the Journal Impact Factors of all five titles in 2017, leading to the original Editorial Expression of Concern. In addition, we found continuing distortion in four of these titles in 2018, leading to their suppression from the 2019 JCR.

The three following journals are suppressed from the JCR for citation stacking: Nanoscience and Nanotechnology Letters, Journal of Biobased Materials and Bioenergy, Journal of Biomedical Nanotechnology.  

We found no anomaly in the content, citations, or authorships of Bone Research in the years reviewed.  Unfortunately, the distortion of the  Bone Research  metrics, introduced by citation stacking from the journals listed above prevents us from publishing accurate 2018 JCR citation data, and the title will not be listed in the JCR this year.

The  Journal of Nanoscience and Nanotechnology  did not show evidence of anomalous patterns of citation in 2018 and will not be suppressed. 

Similar analysis of year to date 2019 indicated no continuation of the citation anomalies, so that the journals will not be removed from indexing in Web of Science at this time.


More details

Four journals in 2017, and three in 2018, contained a pattern of citations concentrated to the JIF numerator of each of the other journals in the set:

  • Nanoscience and Nanotechnology Letters  (2017, 2018)
  • Journal of Biobased Materials and Bioenergy (2017, 2018)
  • Journal of Biomedical Nanotechnology  (2017, 2018)
  • Journal of Nanoscience and Nanotechnology  (2017)

We will refer to these journals collectively as “the Citing Journals.”

The four Citing Journals published sets of articles characterized by large numbers of cited references concentrated exclusively to the prior two years of content in  Bone Research  or one of the other journals in the set under investigation.  For some articles in this group, references that contributed to the JIF represented 50% of their total reference list, and over 90% of their references to any content in the prior two years of scholarship.

The references demonstrated additional abnormal characteristics:

  • The articles contain few or no references to published works on bone biology and research other than the concentrated citations to  Bone Research .
  • The references are primarily located in introductory or discussion sections of the papers as generalized, non-specific demonstrations that the subject being discussed in the paper is being actively researched.
  • The references appear in bulk, from five to as many as 30 in a single body-text reference.

The majority of over 13,000 authors in the five journals had regular publication patterns. However, a small cluster had large numbers of papers published in more than one of the Citing Journals. Three authors published over 50 papers in one or more of the Citing Journals.  These authors were also affiliated with the editorial board of one or more of the Citing Journals.  Finally, each had one or more highly cited papers in  Bone Research  that appear in that year’s JIF denominator as citable items.

Overlapped editorial boards and repeated authorship among a subset of the journals contributed to the magnification of the JIFs.

The net result of these actions has been a gross distortion of the JIF of  Bone Research, and each of the Citing Journals, and elevated citation rates for groups of individual articles authored or co-authored by members of the editorial management of the Citing Journals.

We have communicated with the affected publishers throughout, and have been assured of their cooperation and internal review of the matters described to them.



JCR Editorial Expression of Concern – 2018

It has come to the attention of the editorial and management team for the Journal Citation Reports that there has been a problematic pattern of citations amongst the journals Nanoscience and Nanotechnology LettersJournal of Biobased Materials and BioenergyJournal of Biomedical Nanotechnology and Journal of Nanoscience and Nanotechnology (all published by American Scientific Publishers), and including a particular concentration of citations to the journal Bone Research (published by Springer Nature, in partnership with the West China School of Stomatology, Sichuan University, and the International Chinese Musculoskeletal Research Society).

The possibility of manipulation of citation metrics is a serious matter, and we are the original bibliometrics provider to monitor, survey and curate our data to identify anomalies that lead to distorted rankings.

We have initiated a process of investigation of the journals named above, along with affiliated publications. When we have completed a thorough review, we will take any appropriate action; this may result in one or more journals being removed from the JCR, with a possible further action of removal from indexing in Web of Science.

Because these citations have affected the published metrics for several journals, Clarivate Analytics is publishing this Editorial Expression of Concern to alert our users to this information.