Publication integrity in orthopaedic journals: the self-citation in orthopaedic research (SCOR) threshold.

Abstract

The impact factor (IF) is the most commonly used bibliometric method for rating academic journals. However, the practice of journals' self-citation may artificially elevate the IF. Additional bibliometric methods including Eigenfactor scale, SCImago Journal Ranking (SJR), and corrected IF (cIF) have been created. Comparing general-interest and specialized orthopaedic journals, the aims of this study were to assess: (1) the effect of journal´s self-citation on IF; (2) differences in bibliometric analysis; and (3) to determine thresholds for monitoring self-citation practices by defining the self-citation in orthopaedic research (SCOR) Threshold. The journal citation reports and SCImago Journal and Country Rank databases were queried for orthopaedic journals from 1997 to 2017. The following bibliometrics were compared between general-interest and specialized journals: IF, cIF, Eigenfactor, self-citation rates, and SJR. A novel metric, the cIF ratio, was proposed to represent the relationship between a journal's IF and cIF. Thresholds for cIF were based on statistical outliers of cIF ratio within general-interest and specialized journals were calculated. Outliers were defined as data points that were greater than the third quartile by 1.5 times the interquartile range using the last 10years studied (2007-2017). Specialized orthopaedic journals had a higher median self-citation rates compared to general-interest journals (11.85% vs. 6.36%, p < 0.001). Overall, cIF ratio declined over study period, and general-interest journals had a lower cIF ratio than specialized journals (8.77% vs. 19.54%, p < 0.001). Overall, general-interest journals had more favourable values for the bibliometric indices studied compared to specialized journals The SCOR threshold for cIF ratio was determined as 25.4% for general-interest journals and 53.3% for specialized journals. Overall, self-citation occurs at a higher rate in specialized versus general-interest orthopaedic journals. We propose the use of a cIF ratio along with the SCOR threshold as a tool to evaluate and monitor journal self-citation practices in orthopaedic research.