Why do some journals get their Impact Factor suppressed?
Clarivate removes journals from Journal Citation Reports when it identifies patterns that artificially inflate the Impact Factor. The most common reason is excessive self-citation, but citation cartels (groups of journals citing each other systematically) also trigger suppression. Suppressed journals are excluded from that year's release; some return the following year after fixing patterns, others do not.
Detail
The main triggers
Watch for: excessive self-citation, anomalous citation patterns (citation cartels), retracted paper impact, failure to meet indexing criteria. All can lead to a journal being suppressed from JCR release.
Excessive self-citation
Every journal has some self-citation (an author cites their own earlier work in the same journal, or a follow-up to a series). Clarivate tolerates this. What triggers suppression is a pattern — the journal's editors systematically encouraging citations to boost the next year's JIF.
Citation cartels
Groups of journals that agree, formally or informally, to cite each other. This artificially raises everyone's numbers. Clarivate has become better at detecting these; suppressions for cartel behaviour have increased year-over-year.
Impact of retracted papers
Since 2021, Clarivate excludes citations to and from retracted content from the JIF numerator. A journal with many retracted papers can see its JIF drop even without misconduct — the retracted works no longer accrue citations.
What suppression means for authors
If your paper was published in a journal that later gets suppressed, the paper itself is still legitimate. But your CV entry may need footnoting: 'published in [Journal], suppressed from JCR [year]'. This is a signal to promotion committees.