To the Editor: The 2-year impact factor (IF) from Journal Citation Reports (JCR) is the most commonly used bibliometric index for assessing the influence of a scientific journal. It reproduces the citations of articles within JCR publications over the previous 2 years.1 In 2019, the Journal of the American Academy of Dermatology (JAAD) had 4296 citations from 519 citable articles published in 2018 and 2019, resulting in a 2019 IF calculated as 4296/519 = 8.277.
The time trend of a specific journal's IF can reflect effective editorial policies.2 However, self-citations, open access, industry sponsorship, type of article (eg, reviews), amount of citable articles, and social interest (eg, COVID-19) have been proven to influence the IF.2 , 3
Several indexes have been proposed to assess different aspects of scientific influence. For example, the Immediacy Index reflects the citations of articles in the same year they were published, indicating that the contemporaneity of the journal matters. Because up to 20% of a journal's IF can be inflated through self-citations, the 2-year IF without self-citations reflects the actual external influence of the articles. The Eigenfactor Score is a 5-year index weighted by the influence of the citing journals in the entire JCR network, which results in a robust bibliometric index to evaluate the impact of a journal, because self-citations are excluded, despite being inflated by the amount of citable articles of the journal.4 , 5
Here, we report a 10-year analysis on 3 bibliometric indexes of the main dermatology journals: IF, Eigenfactor Score, and Immediacy Index. The median IF of dermatology journals increased by 27.1% (from 1.667 to 2.118), whereas the dermatology journals accounted for in JCR increased by 23.6% (from 55 to 68) between 2010 and 2019.
The 5 highest-rated dermatology journals in 2019 accounted for 38.1% of all dermatology citations (107,634 of 282,798). A greater IF increase in the last decade was observed in journals that publish preferably clinical articles (Fig 1 ): JAAD (94%), JAMA Dermatology (83%), and the British Journal of Dermatology (61%).
Fig 1.
Trends in the 2-year Journal Citation Reports impact factor for the 5 highest-rated dermatology journals. JAAD, Journal of the American Academy of Dermatology—2019: 4296 citations; JAMAderm, JAMA Dermatology—2019: 1834 citations; JID, Journal of Investigative Dermatology—2019: 3486 citations; BJD, British Journal of Dermatology—2019: 3836 citations; JEADV, Journal of the European Academy of Dermatology and Venereology—2019: 2,944 citations.
The trend of the Eigenfactor Score for these journals (Fig 2 ) disclosed a noteworthy performance of Journal of the European Academy of Dermatology and Venereology (91%), in contrast to the Journal of Investigative Dermatology (−33%), while the other journals had a slight variation of this index.
Fig 2.
Trends in the 2-year Journal Citation Reports Eigenfactor Score for the 5 highest-rated dermatology journals. JAAD, Journal of the American Academy of Dermatology—2019: 283 citable articles; JAMAderm, JAMA Dermatology—2019: 109 citable articles; JID, Journal of Investigative Dermatology—2019: 218 citable articles; BJD, British Journal of Dermatology—2019: 237 citable articles; JEADV, Journal of the European Academy of Dermatology and Venereology—2019: 308 citable articles.
Finally, the Immediacy Index has confirmed the increase in the rising influence of the dermatology clinical journals: JAAD (388%), British Journal of Dermatology (383%), JAMA Dermatology (235%), and Journal of the European Academy of Dermatology and Venereology (126%). Supplemental Fig 1 (available via Mendeley at https://data.mendeley.com/datasets/t33tkw2cpw/1) presents the trend on Immediacy Index, and Supplemental Table I presents the 2019 most important bibliometric index from the 20 highest-rated dermatology journals.
Clinical journals account for most of the citations and overall impact in dermatologic science. The performance of dermatology journals regarding their bibliometric indexes is important in competing for research funding or scholarships.5
Finally, bibliometric indexes are based on the performance of all articles from a specific journal. A high-impact journal is not a guarantee of value for an article published in it, nor are only weak articles published in low-impact journals. Furthermore, it is time to move forward in understanding other bibliometric indexes for a more complete evaluation of journals' scientific influence.4
Footnotes
Funding sources: None.
Conflicts of interest: None disclosed.
IRB approval status: Not applicable.
Reprints not available from the authors.
References
- 1.Yuen J. Comparison of Impact Factor, Eigenfactor Metrics, and SCImago Journal Rank Indicator and h-index for neurosurgical and spinal surgical journals. World Neurosurg. 2018;119:e328–e337. doi: 10.1016/j.wneu.2018.07.144. [DOI] [PubMed] [Google Scholar]
- 2.Nestor M.S., Fischer D., Arnold D., Berman B., Del Rosso J.Q. Rethinking the Journal Impact Factor and publishing in the digital age. J Clin Aesthet Dermatol. 2020;13(1):12–17. [PMC free article] [PubMed] [Google Scholar]
- 3.Mansour A.M., Mollayess G.E., Habib R., Arabi A., Medawar W.A. Bibliometric trends in ophthalmology 1997-2009. Indian J Ophthalmol. 2015;63(1):54–58. doi: 10.4103/0301-4738.151471. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Time to remodel the journal impact factor. Nature. 2016;535(7613):466. doi: 10.1038/535466a. [DOI] [PubMed] [Google Scholar]
- 5.Rodríguez-Lago L., Molina-Leyva A., Pereiro-Ferreirós M., García-Doval I. Influence of article type on the impact factor of dermatology journals. Actas Dermosifiliogr. 2018;109(5):432–438. doi: 10.1016/j.ad.2018.01.003. [DOI] [PubMed] [Google Scholar]