Background: One of the disadvantages of the Impact Factor (IF) is self-citation. The SCImago Journal Rank (SJR) indicator excludes self-citations and incorporates quality of citations that a journal receives by other journals, rather than absolute numbers. This study re-evaluated self-citation influence on the 2007 IF for 17 major orthopaedic journals and the difference in ranking using IF or SJR was investigated.
Methods: Divided in a general (n = 8) and specialized (n = 9) group, all journals were analysed for self-citation rate, self-cited rate and citation density. Rankings of the 17 journals for IF and SJR were determined and the difference in ranking was calculated.
Results: Specialized journals had higher self-citation rates (p = 0.05), self-cited rates (p = 0.003) and lower citation-densities (p = 0.01). Both groups correlated for self-citation rate and impact factor (general: r = 0.85 ; p = 0.008) (specialized: r = 0.71 ; p = 0.049).
When ranked for SJR instead of IF, five journals maintained rank, six improved their rank and six experienced a decline in rank. Biggest differences were seen for BMC MD (+7 places) and CORR (− 4 places). Group-analyses for the IF (general: 7.50 – 95%CI 3.19 to 11.81) (specialized: 10.33 – 95%CI 6.61 to 14.06) (p = 0.26), SJR (general: 6.63 – 95%CI 2.66 to 10.60) (specialized: 11.11 – 95%CI 7.62 to 14.60) (p = 0.07) and the difference between both rankings (general: 0.88 – 95%CI –1.75 to 3.50) (specialized: − 0.78 – 95%CI –2.20 to 0.65) (p = 0.20), showed an enhanced underestimation of sub-specialist journals.
Conclusion: Citation analysis shows that general journals tend to use more citations per published article and a larger portion of self-citations constitutes citations of sub-specialist journals compared to more general journals. The SJR excludes the influence of self-citation and awarded prestige by the SJR implies a different quality-evaluation for most orthopaedic journals. A disadvantage using this indicator, is an enhanced effect of underestimation of sub-specialist journals.
