Rising Influence: ‘Impact Factor’ of Society’s Journals Is Up

By Richard T. O'Grady, Chief Publications Officer; and Andrew Harmon, Director of Publishing Analytics and Development Editor

The Endocrine Society has been publishing cutting-edge research for more than 100 years, a milestone that we always are proud to tout. In fact, many of the endocrinology field’s seminal scientific discoveries and clinical breakthroughs over the past century were first revealed in the pages of our peer-reviewed journals. 

Endocrinology came to life in January 1917. Today our suite of journals has grown to four mastheads: Endocrine Reviews, The Journal of Clinical Endocrinology & Metabolism, Endocrinology, and Journal of the Endocrine Society.

We’re proud to note that the Society’s journals are more influential than ever. How do we know this? Three of our journals experienced significant “Impact Factor” increases last year, according to Clarivate Analytics’ recently released Journal Citation Report (JCR) for 2020, and our fourth and newest journal, the open access Journal of the Endocrine Society, is well-positioned to be considered for an Impact Factor next year.

Rising Impact Factors

The global analytic firm’s annual Impact Factor reports are a closely watched metric of influence in the highly competitive world of scholarly journals. 

The Society ranked 5th among publishers in the JCR category of “Endocrinology & Metabolism,” with an average Impact Factor of 10.188. Last year Clarivate categorized 179 journals in this category, of which 145 had an Impact Factor. 

Impact Factors and corresponding rankings are determined by the number of citations each journal receives. Specifically, Clarivate examines the following:

• Impact Factor is calculated by tracking how many times articles that a journal published during a two-year span were cited by authors during the subsequent third year. The number of citations is then divided by the total number of citable articles published in that journal in those two years.
• Immediacy Index looks at the number of articles published in a single year and averages their resulting citations within the same year.
• Citable is another term for scientific content. Clarivate indexes all journals individually and rules out items that are not seen as regular, editorial material. Items eliminated from the denominators above include editorials, errata, publisher’s notices, conference proceedings, meeting abstracts, and correspondence (letters to the editor and their responses).
• Cited Half-Life refers to the median age of articles cited in the given year. It measures citations in only one year, but it looks at the age of every article that is cited. Example: a Cited Half-Life of 10 in 2020 means that half the journal’s articles cited in 2020 were published in or prior to 10 years ago, and half were published within 10 years of 2020.

In 2020, all four Society journals combined received more than 155,000 citations. 

• Endocrine Reviews: The journal saw the biggest increase in Impact Factor, rising from 14.661 in 2019 to 19.871 in 2020. It ranks No. 4 in the category “Endocrinology & Metabolism,” behind Nature Reviews Endocrinology, Lancet Diabetes & Endocrinology, and Cell Metabolism.
• The Journal of Clinical Endocrinology & Metabolism: JCEM’s Impact Factor increased from 5.399 in 2019 to 5.958 in 2020. It publishes the second highest volume of articles in the category “Endocrinology & Metabolism” and is the most cited journal in the category, with more than 90,000 citations in 2020. In 2018, JCEM’s cited half-life surpassed 10 for the first time, meaning that the average citation lifespan of an article in JCEM is at least 10 years at its peak and 20 years at its longest.
• Endocrinology: The Society’s flagship basic science journal saw its Impact Factor increase from 3.934 in 2019 to 4.736 in 2020, and the publication has the highest cited half-life in “Endocrinology and Metabolism.” It is the sixth most-cited journal in that category, earning more than 46,000 citations in 2020. Endocrinology’s cited half-life has exceeded 10 since 2015.
• Journal of the Endocrine Society: Launched in January 2017, the Society’s open-access journal so far has not been assigned a Journal Impact Factor. Society staff monitor its citation activity using Clarivate’s Emerging Sources Citation Index. The journal is in the 2020 JCR, and in 2020, it received more than 1,600 citations.

Putting the Numbers in Context

Clarivate’s 2020 JCR included 20,932 publications with a Journal Impact Factor. An additional 5,742 titles had no Journal Impact Factor last year. Each journal was indexed into one or more of Clarivate’s 254 scientific categories.

Impact Factors and other metrics are not perfect measurements, and many publishers argue against relying on them unilaterally. Additional details, including comments on changes that Clarivate has made to its calculation methods, are provided in our Author Resources Center.

We’d also note that journals vary by practice and scientific specialty, and each practice and specialty has a different average rate of citations. Also, journal types vary. Review journals tend to have higher Journal Impact Factors than clinical journals, which tend to have higher Journal Impact Factors than basic science journals. 

Megajournals, especially ones with high acceptance rates, do not tend to publicize the Journal Impact Factor because theirs tend to be low as a result of the volume of content being published, much of which doesn’t get cited at all or immediately.

On the other hand, high-publicity journals with a brand awareness transcending a single practice or specialty, especially one of a moderate or small size, will perform more successfully than one with a narrow specialty, even if that narrow journal is well regarded internationally. Clarivate also accounts for journals’ self-citations (an article citing another article in the same journal), displaying statistics and offering an alternative Journal Impact Factor without them.

To accommodate journals whose citation activity is better measured over a longer period of time, JCR offers a 5-year Impact Factor, which, in this case, averages citations in 2020 to journal articles published in 2016–2019 (four published years + 1 citation year = 5 years).

Continuing the Tradition of Excellence

Publishing peer-reviewed journals is a natural part of the Society’s mission to unite, lead, and grow the global community of researchers, educators, and practitioners in endocrinology. It is an endeavor that can only be accomplished when that same community vigorously participates in the Society’s journals as authors, editors, reviewers, and readers — again, on an inclusive, global scale.

Fortunately, our membership is very engaged, and we have maintained high levels of participation with the journals over the decades. We also have a deep pool of leadership talent from which to draw. 

We recently announced the appointment of two outstanding new Editors-in-Chief. Ashley Grossman M.D., F.R.C.P., of Barts and the London School of Medicine in London, U.K., will succeed Daniel J. Drucker, MD, of University of Toronto and Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, Toronto, Ontario, Canada, to lead Endocrine Reviews; and Zeynep Madak-Erdogan, Ph.D., of the University of Illinois at Urbana-Champaign, will succeed J. Larry Jameson, MD, PhD, of the University of Pennsylvania, to lead the Journal of the Endocrine Society. 

Drs. Grossman and Madak-Erdogan start their three-year terms in on January 1, 2022. They join our on-going Editors-in-Chief, Paul M. Stewart, MD, FRCP, FMedSci, of University of Leeds, Leeds, U.K., with JCEM; and Carol A. Lange, PhD, of University of Minnesota, with Endocrinology.

With our Editors-in-Chief and their teams, we continually expand our efforts to publish the very best articles in our journals, across all topic areas. We utilize professional networking, conference attendance, literature research, and a variety of online metrics — including citations, Altmetric scores, h index, and preprints — to identify authors and key topics around the world. Then we follow up with personal contacts to authors to encourage and invite submissions of research articles, reviews, commentaries, and other article types. 

We also look for innovative ways to share journal content with readers. Each month, we publish online a thematic issue of top articles on a given topic drawn from across our journals. And last year we created the Endocrine Feedback Loop, a journal club podcast series that features an expert educator and a topical specialist dissecting recently published journal articles and discussing implications for clinical practice. 

In our online Author Resource Center, authors can find information, services, and advice — including language editing and graphics preparation services. 

Finally, we encourage all members to follow the journals on Twitter, @EndoSocJournals, where you can learn of the latest journal developments and find new content releases. Authors also can share their work here, and the Endocrine Society will re-tweet posts when they mention @EndoSocJournals and use the corresponding hashtags: #JCEM, #EndocrineReviews, #Endocrinology, or #JES.