Beyond impact factor: citation skew and article-level influence in sleep medicine journals.

Abstract

Citation skew refers to the unequal distribution of citations to articles within a journal. The study aimed to assess citation skew in sleep science journals and whether the journal impact factor (JIF) predicts individual article citation rates. The top ten sleep science journals were identified via the Journal Citation Report (JCR), and the number of citations in 2022 for all original and review articles from 2020 to 2021 was analyzed. Among 3,949 articles with 16,373 citations, a substantial proportion had either zero (16.0%) or one citation (18.7%) in 2022. Only 27.7% of articles exceeded their journal's JIF, while 72.3% fell below it. Review articles demonstrated higher citation rates than original research. Citation distribution was highly skewed, with 12.5% of articles accounting for 50% of all citations. Although citation rate correlated significantly with JIF (r = 0.21, p < 0.001), JIF explained only ~ 4.4% of the variance in article-level citations. Citation distributions in leading sleep journals are highly skewed, and journal impact factor has limited utility for predicting individual article influence. These findings support interpreting JIF cautiously and emphasize the value of article-level indicators and qualitative appraisal when assessing research impact. Future studies incorporating multiple JIF cycles and article-level citation provenance, including self-citation and citation-network effects, are needed to better characterize the drivers and temporal stability of citation behavior in sleep medicine.