Impact Factor Denied to 20 Journals For Self-Citation, Stacking

This year, Clarivate Analytics, publishers of the Journal Citation Reports (JCR), suppressed 20 journals, 14 for high levels of self-citation and six for citation stacking — a pattern known informally as a “citation cartel.” In addition, it assigned an Editorial Expression of Concern to five journals after it became aware of citation anomalies following the completion of the 2018 report. Suppression from the JCR lasts one year.

Police officer writing ticket

Titles are suppressed when either self-citation or stacking distorts the Journal Impact Factor (JIF) and rank of a journal such that it does not fairly reflect the journal’s citation performance in the literature. This can happen through self-citation, particularly when there is a concentration of citations to papers published in the previous two years, or when there is a high level of JIF-directed citations between two or more journals. The first citation cartel was identified in 2012, involving four biomedical journals. Other cartels have been identified in soil sciencesbioinformatics, and business. The JCR publishes annual lists of suppressed titleswith key data and descriptions.


Full Title Category % Self cites in JIF numerator % Distortion of category rank
Aquaculture Economics & Management Fisheries 56% 35%
Archives of Budo Sport Sciences 45% 34%
Canadian Historical Review History 63% 49%
Chinese Journal of International Law International Relations 51% 33%
Chinese Journal of International Law Law 51% 34%
Chinese Journal of Mechanical Engineering Engineering, Mechanical 48% 27%
Eurasia Journal of Mathematics Science and Technology Education Education & Educational Research 62% 36%
International Journal of American Linguistics Linguistics 64% 36%
International Journal of Applied Mechanics Mechanics 48% 36%
International Journal of Civil Engineering Engineering, Civil 59% 27%
Journal of Micropalaeontology Paleontology 51% 40%
Journal of Voice Otorhinolaryngology 47% 45%
Maritime Policy & Management Transportation 54% 31%
Pediatric Dentistry Dentistry, Oral Surgery & Medicine 48% 44%
Pediatric Dentistry Pediatrics 48% 33%
Psychoanalytic Quarterly Psychology, Psychoanalysis 70% 46%


Recipient Journal Donor Journal % JIF Numerator % Exchange to JIF Years
European Journal of the History of Economic Thought History of Economic Ideas 56% 86%
Journal of the History of Economic Thought History of Economic Ideas 64% 88%
Liver Cancer Digestive Diseases 40% 95%
Liver Cancer Oncology 23% 85%


  • Nanoscience and Nanotechnology Letters
  • Journal of Biobased Materials and Bioenergy
  • Journal of Biomedical Nanotechnology
  • Journal of Nanoscience and Nanotechnology
  • Bone Research

The JCR has a public document explaining the guidelines it uses to evaluate journals for suppression. However, as illustrated through reverse engineering previously suppressed titles, threshold levels are set extremely high, so high, that a journal that increased its Impact Factor by nearly 5-fold and moved to first-place among its subject category can escape suppression. Nevertheless, suppression from the JCR has been shown to drastically reduce levels of self-citation following reintroduction. If the JCR were traffic cops, they appear to be stopping only the most reckless drivers.