Self-citation rates among medical imaging journals and a possible association with impact factor

Purpose: Since conceptualisation in 1955, journal impact factors (IFs) have evolved as surrogate markers of perceived 'quality'. However, no previous research has explored the relationship between IF and journal self-citation rate, which may inflate this measure. Given Radiography's ongoing push to achieve Medline and ISI database inclusion, this paper aimed to quantitatively explore the frequency of self-citation and correlate this with ISI-reported IF. Methods: A review of articles published in two peer-reviewed, Medline and ISI-listed, imaging journals (Radiology and Academic Radiology), and Radiography, within in a 12-month period, was performed. The total number of citations and self-citations per article was recorded, and the results compared. Basic statistical and correlation analyses between listed IF ratings and self-citation indices were also performed. Results and Discussion: To our knowledge, this work represents the preliminary investigation exploring the association between ISI-listed IF and self-citation frequency. From the current results it can be suggested that such a relationship does exist, as demonstrated by the strongly positive correlation statistic (Pearson's r2 = 0.99). Radiology was noted to have a considerably larger mean number of self-citations per article than the other two journals (p < 0.01), despite near-equivalent numbers of references per article. Conclusion: Our findings suggest that there may be relationship between an ISI-listed IFs and journal self-citation rates. It is hoped that this paper will be of interest in academic and research circles, both within medical imaging and more widely, and may provide impetus for discussion relating to self-citation frequency and influence on resultant IF calculations.