Subspecialty Virtual Impact Factors within a Dedicated Neuroimaging Journal

Discussion

Citation patterns of Original Research and Review Articles in AJNR varied widely on the basis of subsections, with Review Articles accumulating the greatest number of citations within the first 2 years after publication. Understanding these citation patterns for specific topics and subsections of a journal may aid editors in evaluating the appropriate balance between topics and allow authors to determine whether their articles are being cited at levels expected for similar topics in a journal.

The highest number of citations was for articles classified as “Expedited Publication,” which is not unexpected because these are presumably important and timely topics. Thus, encouraging the submission of such articles has the potential to influence the Impact Factor of a journal. Expedited peer review and waived fees, such as those for color figures or article length, may be ways to encourage such submissions as AJNR does.

Articles that received the designation of “Editor's Choice” and “Fellows' Journal Club” were cited more often than others in their given journal categories. These designations are chosen by the Editor-in-Chief, and it is possible that the assigned designations improved recognition of the articles and resulted in increased citations. In addition, the articles chosen for these categories are usually those with state-of-the-art topics, clinically important, and of higher evidence-based levels, which may also contribute to their increased citations. Articles related to spine intervention trended toward a higher number of citations than diagnostic spine articles overall, probably because they are viewed and cited by specialists outside of just imaging.

Limitations in our study include the inability to determine the exact parameters that compose the official JIF because this is a proprietary algorithm that is modified with time. Additionally, the JIF changes with time, and we only used a single JIF for this investigation, the 2013 JIF, which was the most recent one available at the time of analysis. As with all citations, it is not possible to determine citations when the original article serves as a foundation for future work or when it is criticized or refuted. Many articles are well-received by readers, becoming popular reading but are not cited. One of the reasons many journals have decreased or eliminated case reports, despite their popularity among readers, is the negative effect on the JIF. We created our VIF on the basis of citations in the first 2 years after publication, mirroring the methodology of the JIF. The JIF also can be calculated for other periods of citations, in particular the 5-year JIF, which may give additional information about the longevity of impact of an article; however, we chose to perform a 2-year analysis because the 2-year JIF is the most commonly used metric.

The resultant quality of articles in a journal is a factor of the quality of work being performed in a given area, the alternative outlets for publication that a given author may choose, and the quality of the editorial review process. It is possible that areas such as interventional, in which many reviewers practice for a large percentage of their careers, receive higher quality reviews because the reviewers want to simultaneously select the best articles and provide the best feedback to the authors during the review process to improve the articles. In contrast, a smaller number of radiologists have most of their practice in head and neck and likely even fewer have their practice and academic interests primarily in spine.

Beyond neuroradiology journals, there are spine-focused journals in neurosurgy and orthopaedic surgery (eg, Journal of Neurosurgery–Spine, and Spine). These 2 journals have JIFs of 2.355 and 2.447, respectively, very similar to the 2.319 VIF for articles with a spine topic in AJNR. Comparisons such as this may help determine whether subsections and/or topics are being cited like those in journals with a potentially overlapping focus.

Knowledge of subsection VIF may allow prediction of the influence on the JIF, with reallocation of journal pages between sections. Page allotment limitations from print journals may be mitigated as they shift toward on-line publications.

Because the financial and logistic barriers for creating larger new journals has decreased, it may be tempting for physicians with a narrow area of interest to contemplate creation of a focused journal on a given topic, and understanding citation trends may provide evidence that a narrowly focused journal may or may not have the ability to survive. For example, it is clear from our investigation that for subspecialties such as spine and head and neck imaging, creating their own freestanding journals may be difficult and physicians are better served by remaining within a larger journal with a higher JIF than they would in independent journals dedicated to their specialty. In addition, authors of articles with a given topic may be able to better recognize the expected citations of their article and whether submitting to a specific journal such as AJNR is best for them. For instance, the author of a diagnostic spine imaging article in AJNR, which will have fewer citations than the average article in the journal, may be less discouraged if they know their article has been cited more than other diagnostic spine articles in the same or other journals. Thus, encouraging all journals to calculate and publish their virtual JIF by sections may be useful to prospective authors.