Impact factor correlations with Scimago Journal Rank, Source Normalized Impact per Paper, Eigenfactor Score, and the CiteScore in Radiology, Nuclear Medicine & Medical Imaging journals

Radiol Med. 2019 Jun;124(6):495-504. doi: 10.1007/s11547-019-00996-z. Epub 2019 Feb 6.


Introduction: In the last decade, several journal's editors decided to publish alternative bibliometric indices parallel to the impact factor (IF): Scimago Journal Rank (SJR), Source Normalized Impact per Paper (SNIP), Eigenfactor Score (ES) and CiteScore™ (CiteScore); however, there is scarce information about the correlations among them. In this study, we aimed to evaluate the associations between this bibliometrics in the Radiology, Nuclear Medicine & Medical Imaging category of the Web of Knowledge. We hypothesized the IF did not show the best correlation with other metrics.

Methods: Retrospective study. We used bibliometrics recorded from the 2017 publicly available versions of the Journal Citation Reports (JCR), SJR ( ), SNIP ( ), and CiteScore ( ); we also included the Total Cites. We measured the correlations using the Spearman correlation coefficients (RS) for all combinations of the bivariate pair, performed pairwise comparisons of the RS values, and calculated the coefficients of determination. We also tested the statistical significance of the difference between r coefficients between groups. All analyses were conducted with the JMP Pro software.

Results: The stronger bivariate correlations were represented by the ES↔Total Cites RS = 0.968, p < 0.001, R2 = 0.937; and the CiteScore↔SJR RS = 0.911, p < 0.001, R2 = 0.829. From 105 possible combinations of pairwise comparisons, 38 depicted a p value > 0.050 which would suggest interchangeability among bivariate correlations.

Conclusions: Our findings support our hypothesis that the IF does not show the best correlation between other metrics. Radiologists, interventional radiologist, or nuclear medicine doctors should have a clear understanding of the associations among the journal's bibliometrics for their decision-making during the manuscript submission phase.

Keywords: Algorithms; Bibliometric analysis; Citation; Journal impact factor; Literature-based discovery.

MeSH terms

  • Bibliometrics*
  • Diagnostic Imaging*
  • Humans
  • Journal Impact Factor
  • Models, Statistical
  • Nuclear Medicine*
  • Radiology*
  • Retrospective Studies