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.
2021 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 (JIF)™ 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. Although this pattern of citation distorts the JIF and rank in category, it does not meet the current parameters for suppression for journal self-citation. Instead, our concern regarding this unusual activity has been flagged as an Editorial Expression of Concern in JCR Help.
An Editorial Expression of Concern of is not a suggestion of citation manipulation or deliberate action on the part of the journal.
The data that raised this concern are fully transparent to all JCR users through the Journal Impact Factor Contributing Items in the Citing journals feature.
In 2022, suppression analysis of the 2021 JCR data will include review of items with an atypically large contribution of journal self-citations to the JIF numerator. The specific parameters for this analysis are not yet final.
| Journal Title | JIF Numerator | Highest Single-Paper Journal Self-Citations | Total Journal Self-Citations |
| Arteriosclerosis Thrombosis and Vascular Biology | 3974 | 189 | 582 |
| Artificial Organs | 889 | 124 | 260 |
| British Journal of Biomedical Science | 268 | 50 | 77 |
| Clinical and Translational Allergy | 546 | 61 | 86 |
| European Journal of Epidemiology | 1677 | 180 | 209 |
| European Journal of Histochemistry | 255 | 69 | 80 |
| Histochemistry and Cell Biology | 792 | 58 | 92 |
| International Journal of Cardiovascular Imaging | 1021 | 109 | 186 |
| Journal of Allergy and Clinical Immunology-In Practice | 3895 | 147 | 664 |
| Journal of Neurosurgical Anesthesiology | 358 | 91 | 117 |
| Journal of Raman Spectroscopy | 1273 | 200 | 320 |
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 (JIF)™ 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. Although this pattern of citation distorts the JIF and rank in category, it does not meet the current parameters for suppression for journal self-citation. Instead, our concern regarding this unusual activity has been flagged as an Editorial Expression of Concern in JCR Help.
The data that raised this concern are fully transparent to all JCR users through the Journal Impact Factor Contributing Items in the Citing journals feature.
| Journal Title | JIF Numerator | Highest Single-Paper Journal Self-Citations | Total Journal Self-Citations |
| Annals of Allergy, Asthma & Immunology | 1,605 | 66 | 605 |
| Applied Surface Science | 38,702 | 111 | 9,432 |
| Artheriosclerosis, Thrombosis and Vascular Biology | 3,368 | 119 | 1,344 |
| Artificial Organs | 707 | 155 | 777 |
| British Journal of Biomedical Science | 198 | 52 | 136 |
| Cardiovascular Research | 2,335 | 105 | 632 |
| International Archives of Allergy and Immunology | 524 | 86 | 122 |
| JACC-Cardiovascular Imaging | 2,772 | 127 | 1,493 |
| Journal of Allergy and Clinical Immunology-In Practice | 1,024 | 191 | 494 |
| Journal of Cardiovascular Magnetic Resonance | 47,493 | 102 | 27,429 |
| Journal of Cleaner Production | 2,790 | 126 | 1,136 |
| Minerva Anestesiologica | 582 | 86 | 375 |
| Respirology | 1,469 | 53 | 437 |
| Sociology of Sport Journal | 166 | 67 | 87 |
| Structural Chemistry | 741 | 72 | 354 |
2019 Summary
Our team 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. 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
- Journal of Nanoscience and Nanotechnology
- 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 following three 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. As such, 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 (Citing 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)
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.
2018 Summary
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 among the following journals, all published by American Scientific Publishers:
- Nanoscience and Nanotechnology Letters
- Journal of Biobased Materials and Bioenergy
- Journal of Biomedical Nanotechnology
- Journal of Nanoscience and Nanotechnology
- 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 Clarivate Analytics is the only bibliometrics provider to monitor, survey, and curate our data to identify anomalies that lead to distorted rankings. We have initiated a process of investigating the aforementioned journals, along with affiliated publications. When we have completed a thorough review, we will take any appropriate action; this may result in us removing journals from the JCR, possibly removing them from indexing in Web of Science.
Because these citations have affected the published metrics for several journals, Clarivate™ is publishing this Editorial Expression of Concern to alert our users to this information.