3.1 H-index Score
H-index score is used as a metric for scientific output which considers the number of publications and the number of times each paper was cited. For example, an h-index of 10 means that an author has published 10 papers, each of which has been cited at least 10 times.1 All other papers that have not been cited by other literature are not included in the h-index score which means the total number of published works is not factored into this metric.
There are multiple academic search engines such as Scopus, Google Scholar, and World of Science, that automatically calculate an author’s h-index alongside other publishing statistics. The most commonly used database, Scopus automatically calculates a researcher’s h-index.2 But this only considers indexable articles which are found online, thus some articles by professors prior to major internet indexing prior to 1996 are likely to vary.2Google Scholar is available to the public for free which is a major advantage, however, discrepancies in h-index calculation have been found. World of Science requires an author’s last name and initials to search for publications which can lead to more time finding results. While Scopus links multiple variations of names and institutions to consolidate the database, Google Scholar does not and thus the calculated scores vary by institution.2
The number of times cited is largely dependent on the journal in which the work was published. For many specialties and subspecialties, journals and magazines are often smaller and not cited as frequently as larger and higher impact journals. Submitting original work to higher impact journals increases the likelihood of being cited, thus influencing a h-index score. It is also important to consider the impact of review articles and meta-analyses as these types of studies would be more likely to be cited than other study designs.3 In addition, keeping track of published work by linking variations of your name to an account on Scopus or ORCID ID would reduce the chance of a publication being missed by automated engines. Given that this metric identifies the greatest common factor between number of publications and number of times cited h-index scores can be inflated by citing one’s own work in subsequent papers. For example, if an author had three publications with three, three, and two citations, respectively, by citing the third paper in the next work, the author’s h-index would rise to three. Increasing one’s h-index score in this way could serve as an incentive to continue expanding upon one’s medical innovation.4
Lastly, although h-index is one of the most popular measures of research output, it is important to briefly discuss other measures that exist. In fact, the g-index and e-index were developed in response to limitations of the h-index score that may start playing a bigger role in the future. G-index was introduced in 2006 and it is defined as “the largest number such that the top ‘g’ articles received together with at least 2 citations”.5 For example, if you have 4 publications with citations of 12, 4, 3, and 0, you will have a g-index of 4 because the sum of citations is greater than 16 but not greater than 25, even though h-index would be 3. One can see how g-index is better at recognizing articles that have received considerably high citations, which shows the publication is valuable to the literature. E-index developed in 2009 is a metric used to be complementary to h-index but catches publications that are highly cited that were underestimated in the h-index.5 Awareness of these measures can be useful as they begin to play potential roles in multi-faceted estimations of impactful research output.
The lack of awareness of one’s personal h-index score or understanding of how the h-index score is calculated can hinder forward progress in academic output. In 2021, a study in Germany attempted to capture all university professors, including professors in medicine, and to measure their knowledge on self-estimating their h-index score. They found about 40% of their sample size of 1017 professors did not know the details of h-index or incorrectly estimated their h-index score when they thought they knew it.6 There was no report on how professors in medicine specifically did on competency of their own h-index score, and to our knowledge, there are no studies in the literature that have evaluated h-index awareness in otolaryngology. Future studies should further investigate the awareness of the h-index score within members of the otolaryngology department including faculty and residents to help determine how much education may be needed.
Further, there appears to be a gender gap between the h-indexes of women and men. While this difference could be attributed to bias, studies have offered a variety of reasons, which could give insight to factors that affect the h-index. Women comprise an underrepresented proportion of academic surgical subspecialties and even less so in leadership positions.7 One reason that women may have lower research productivity is due to the preexisting lack of women in the field and hence less availability of mentors.8 Other factors include having greater roles in supporting family life, educational medicine, or clinical service.8,9 Despite these obstacles, women are capable of raising their h-index to match or exceed their male peers.8 This demonstrates that despite a late start or other obligations, one can still recover later on and achieve higher academic ranking. As mentioned later in our guidelines, however, researching and publishing earlier in the career allows for more exposure, influence, and citations to be made, thus increasing the h-index score.
In an ever increasingly competitive world, measures of aptitude often become more important than the content itself. Though the h-index provides great convenience, it may become a higher priority than actual scientific novelty. Although the h-index measures research productivity, research itself is very diverse in nature. From clinical to bench to case reports, the h-index does not account for the type of research conducted.9,10 Impactful research stems from both basic science and clinical studies however the timeline of each varies greatly. Generally, basic science research takes place over a greater amount of time than clinical studies resulting in less publications. Though the publication could have lasting impacts, it would generally not be able to greatly raise a researcher’s h-index. Each research field has a different h-index compared to other fields so this could alleviate some of the disparity caused by research type. For example, a field focused on time-intensive basic sciences would have a relatively low h-index when compared to a field that mainly publishes fast-paced case reports frequently. While applying within a certain field, the disparity in h-index would likely not cause an issue however it could when translating to another field that has a higher relative h-index. Additionally, it is important to consider that the h-index score could underestimate quality work that is significantly valuable for the medical literature.5 For example, one manuscript can be cited 300 times in the literature but have a collective h-index score of 1 if two other manuscripts only received 1 citation each. G-index and e-index were developed to help amend this flaw, but they have yet to gain as much utilization and popularity as h-index.5