Adjusted Citation Rate, an Alternative Metric to Measure the Impact of General Radiology Journals

Abstract

Rationale and objectives: The journal impact factor (JIF) is often used to assess the prestige of scientific journals. Citations from original articles and reviews as well as citations from noncitable items contribute to the numerator in these calculations. However, since noncitable articles are not included in the denominator, the JIF may be skewed by the types of articles and not accurately reflect the prestige of the journal. The purpose of our study was to develop an alternative and complementary metric by which journals may be assessed. This "adjusted citation rate metric" is based on citations that originate only from citable items in the journal.

Material and methods: We tabulated the number of citations and citable items for original articles from the Web of Science Core Collection for 5 consecutive years (2010-2014) for 20 general radiology journals. The adjusted citation rates (CR) per original article and reviews were calculated using only citations that originated from citable items.

Results: The adjusted CR in 2015 was similar to the JIF in 14 of the 20 journals, higher in four journals, and lower in two journals. Using this system, Radiology, Investigative Radiology, and European Radiology remained first, second, and third respectively among journals published in the field of general radiology. To allow for equal distribution of original articles vs reviews among general radiology journals, we calculated the adjusted CR where the standard distribution of original articles is 50%.

Conclusion: Adjusted citation rate is an objective index for assessing journal impact that can serve as an alternative and complementary metric with which to measure the journal impact.

Keywords: alternative metric; citation rate; journal impact factor; radiology journals.