Introduction
The scientific impact indicators that determine the academic productivity of scientists from all disciplines are important parameters to demonstrate academic performance.Reference Jamjoom, Wiggins, Loan, Emelifeoneu, Fouyas and Brennan1–Reference Efron and Brennan8 For this purpose, the number of published works of an academician and the citations of these works are basic indicators of academic activity. Academic performance is important not only for academic promotion, but also for job vacancies, grant evaluations, tenure and so on.Reference Jamjoom, Wiggins, Loan, Emelifeoneu, Fouyas and Brennan1–Reference Minasny, Hartemink, McBratney and Jang4
The h-index (sometimes referred to as the Hirsch index), which has been used since 2005, is the most commonly used indicator to determine the ranking of academic activity.Reference Jamjoom, Wiggins, Loan, Emelifeoneu, Fouyas and Brennan1–Reference Ortega and Aguillo3 A large number of other indices (bibliometrics) have been introduced to demonstrate academic productivity, including hi-norm, hi-annual, hc-index, g-index, m-quotient and e-index. Every index has some advantages and disadvantages when they are applied to an academician and/or institution to determine academic performance.Reference Minasny, Hartemink, McBratney and Jang4–Reference Doja, Eady, Horsley, Bould, Victor and Sampson9
The h-index is a whole number value that reflects a researcher's ‘h’ number articles, each of which has at least ‘h’ citations. This value is used to indicate the value of these publications. However, this index is clearly greater for senior researchers who have more articles with possible higher citations over a greater period of time. In this regard, this value is not a realistic bibliometrics value when comparing senior and junior scientists. Therefore, a few bibliometrics in addition to the h-index have been introduced to address the disadvantage of this indexing system.Reference Jamjoom, Wiggins, Loan, Emelifeoneu, Fouyas and Brennan1, Reference Venable, Khan, Taylor, Thompson, Michael and Klimo2, Reference De Groote and Raszewski7–Reference Linder, Kamath, Pratt, Saraykar and Volk10 The m-quotient, which was also proposed by Hirsch, uses the h-index divided by the years from the first publication of a particular author. This value can provide a more accurate index to compare senior and junior scientists.Reference Jamjoom, Wiggins, Loan, Emelifeoneu, Fouyas and Brennan1–Reference Ortega and Aguillo3 Similarly, the g-index considers highly cited articles, and the hc-index provides a high value for newer publications compared with older publications.
This study investigated the top 100 otorhinolaryngology and head and neck surgery physicians worldwide under all subspecialties of this main medical branch by ranking them using the h-index. The institutions that these individuals work for were verified by double-checking the institutions’ websites. The physicians’ e-mail addresses in the most recent studies and the institutions’ websites were collected and verified. Reverse checking was also applied to prevent attribution to the wrong studies and incorrect author citation as a result of name similarity.
Materials and methods
The study was performed between June and August 2016, following local ethics committee approval. Google Scholar was scanned, and the h-indices of the scientists worldwide working in the otorhinolaryngology and head and neck surgery specialty, and all subspecialties and specific fields of this branch, were noted. This study exclusively included scientists with available Google Scholar accounts. Scientists without Google Scholar accounts were not included.
An Internet search was performed using different keywords that cover all of the main branches and sub-branches, and we consequently reached out to or identified the scientists. The following keywords were used: otology, otolaryngology, neurotology, head and neck surgery, otorhinolaryngology, rhinology, rhinoplasty, ear, nose, throat, ENT, tinnitus, vertigo, audiology, thyroid surgery, parathyroid surgery, skull base surgery, endoscopic ear surgery, cochlear implantation, ear surgery, inner ear, facial plastic surgery, chronic rhinosinusitis, paediatric otolaryngology, hearing loss, hearing disorders, endoscopic sinus surgery, hearing sciences, speech and communicative sciences, endoscopic endonasal surgery, hearing, sinus surgery, sleep disorders, obstructive sleep apnoea, and medicine.
To prevent mistakes that may occur as a result of name similarities, the first name, middle name (if any), and last name were entered and verified on the Web pages of the institutions where the scientist works. Thus, mistakes that could result from name similarities and working in different branches were avoided.
For scientists with the same h-index, the ranking was made according to the number of citations. If the h-index and the number of citations were the same, the sequence was sorted according to the surname.
Based on the review process and on the reviewer comments, the initial keywords used were not considered to cover all the authors who work in otorhinolaryngology and head and neck surgery. Therefore, we decided to re-perform the search using additional keywords. The revised keywords included: acoustic neuroma, acoustic schwannoma, airway disorders, allergic rhinitis, allergy, antiaging, audiology, auditory brainstem implantation, auditory implants, auditory neurobiology and implantology, auditory neuroscience, auditory physiology, balance, biomechanics of vocal fold vibration, cholesteatoma, chronic rhino sinusitis, chronic sinusitis, clinical practice guidelines, cochlea, cochlear implants, cochlear implantation, congenital hearing loss, common cold and flu, cortex, cranial base, deafness, deafness and hearing loss, dizziness, drug delivery, ear, ear disorders, ear surgery, endoscopic ear surgery, endoscopic surgery, endoscopic sinus surgery, endoscopic skull base surgery, ENT, evidence-based medicine, facial plastic surgery, head and neck oncology, head and neck surgery, hearing, hearing disorders, hearing impairment, hearing loss, hearing sciences, inner ear, imaging, laryngology, laryngeal physiology, medicine, Meniere's disease, microbiome, middle ear, minimally invasive techniques, motion sickness, nasal, nasal and sinus surgery, nasal polyps, nasal polyposis, neural mechanisms of learning, neural prostheses, neuroanatomy, neuroscience, neurosurgery, neurotology, nose, orbital, otitis media, otolaryngology, otolaryngology head and neck surgery, otorhinolaryngology, otology, otology and neurotology, otoneurosurgery, otosclerosis, ototoxicity, pathogenesis of chronic rhino sinusitis, paediatric obstructive sleep apnoea, paediatric otolaryngology, paediatric sleep disorders, plasticity, plastic surgery, psychoacoustics, regeneration, rhinology, rhinoplasty, rhinology and skull base surgery, sinonasal and skull base disorders, sinus, sinusitis, sinus surgery, skull base, skull base disorders, skull base surgery, sleep apnoea, sleep medicine, sleep and snoring disorders, speech, speech and communicative sciences, speech perception, speech production, speech recognition, superior canal dehiscence, surgery, throat, thyroid and parathyroid surgery, tinnitus, tissue engineering, vertigo, vestibular, vestibular implant and prostheses, vestibular system, vestibulology, voice, voice disorders, voice surgery, laser surgery, smell disorders, and odour tests. Consequently, the list of the top 100 scientists changed.
Finally, we checked institutions to ensure that the authors were working in the field of otorhinolaryngology or a subspecialisation. On 15 November 2017, all the information about the authors was revised accordingly, and the study was concluded.
Results
In this study, 36 204 scientists were identified as a result of scanning the keywords listed in the Materials and methods. From these, the scientists who work in otorhinolaryngology and head and neck surgery and sub-branches were selected. Thus, the first 100 scientists were ranked by accessing the Google Scholar information of 5934 scientists from all over the world.
The first 100 scientists who work in otorhinolaryngology and head and neck surgery departments and their sub-branches worldwide were sorted based on their h-index as of 15 November 2017 (Table 1). Given the existence of scientists with the same h-index, we added 3 more scientists; thus, the table reflects the top 103 scientists.
Top 103 scientists worldwide working in ORL-HNS departments and sub-branches*
*Sorted based on the Google Scholar h-index as of 15 November 2017. Note: obtaining the Google Scholar h-index and citations is not possible for scientists who do not have Google Scholar accounts; thus, only scientists with Google Scholar accounts could be listed. SUNY = State University of New York; ORL-HNS = otorhinolaryngology and head and neck surgery
We observed that the h-index of the scientists with the highest h-index varied between 25 and 81 (mean (± standard deviation) = 37.83 ± 11.49). Approximately three-fourths of the scientists working in otorhinolaryngology and head and neck surgery, and its sub-branches, have an h-index score of 30 or greater.
Discussion
The academic performance of scientists is assessed by their publications and references made to their studies. In 2005, the h-index proposed by Hirsh quickly became popular, and currently serves as an important criterion for the quantitative and qualitative evaluation of academic productivity.Reference Jamjoom, Wiggins, Loan, Emelifeoneu, Fouyas and Brennan1–Reference Ortega and Aguillo3, Reference Hirsch11 Although alternative indices have been proposed, the h-index remains the most important academic indicator.Reference Jamjoom, Wiggins, Loan, Emelifeoneu, Fouyas and Brennan1, Reference Doja, Eady, Horsley, Bould, Victor and Sampson9 Thus, we preferred to use the h-index, ranking the top 103 scientists with the highest academic performance in the otorhinolaryngology and head and neck surgery field, including all its sub-branches and special branches.
The most commonly used databases for analysing and evaluating the h-index are: Web of Science, Scopus and Google Scholar. Although these databases have similarities, there are some differences. Within these, Google Scholar has the broadest database. Minasny et al.Reference Minasny, Hartemink, McBratney and Jang4 reported that Google Scholar has 2.3-fold more articles and 1.9-fold more citations than the Web of Science. The Scopus database contains 1.1-fold more articles than the Web of Science, and the number of citations was similar. All results indicate that Google Scholar contains more articles and citations than the other two databases.Reference Minasny, Hartemink, McBratney and Jang4, Reference Falagas, Pitsouni, Malietzis and Pappas12, Reference Kulkarni, Aziz, Shams and Busse13 Regarding potential explanations, the Web of Science scans fewer journals, whereas Google Scholar also includes other publications, such as book chapters and electronic publications. The academic productivity of scientists can be assessed using these databases. In addition, Google Scholar is a free browsing portal accessible to anyone with access to the Internet. In the current study, the Google Scholar database was used to reveal almost all the scientific productivities of the scientists.
Studies on the h-indices of scientists working in several different fields are available in the literature, albeit in limited numbers. Our study is the first to focus on otorhinolaryngology and head and neck surgery, and its related sub-branches and specific branches. In a study based on neurosurgeons’ works in the UK, the average Google Scholar h-index was reported to be 5.Reference Jamjoom, Wiggins, Loan, Emelifeoneu, Fouyas and Brennan1 In another study using the Scopus database, the h-index value was 6.Reference Wilkes, Akram, Hyam, Kitchen, Hariz and Zrinzo14 According to the results from a study on neurosurgeons in the USA, the h-index value was between 11 and 16.Reference Khan, Thompson, Taylor, Venable, Wham and Michael15 In that study, Khan et al. focused exclusively on scientists working in major centres, and excluded a large group of scientists outside of these centres.Reference Khan, Thompson, Taylor, Venable, Wham and Michael15 Thus, the results in that study may not accurately reflect the true h-index. A study of scientists in otorhinolaryngology and head and neck surgery and its related sub-branches, conducted using a national database, revealed that the h-index scores of the top 100 authors were between 4 and 23 (mean, 9.29).Reference Kalcioglu, Ileri, Ozdamar, Yilmaz and Tekin16 In the current study, we sought to obtain a realistic result by including all scientists working in otorhinolaryngology and head and neck surgery, and all subspecialties and specific fields.
All publications related to examining the bibliometric scores of academicians are mostly made on a national basis and partly among certain universities. To the best of our knowledge, no other study has analysed scientists worldwide using h-index scores. The current study is the first in which scientists working worldwide in otorhinolaryngology and head and neck surgery, and its subspecialties and specific fields, have been examined using h-index scores.
In a study on otorhinolaryngology and head and neck surgery physicians in the USA, h-index scores increased significantly in proportion to the title of the academicians, such as assistant professors, associate professors and professors, with average values of 4.62, 8.13 and 15.6, respectively.Reference Svider, Choudhry, Choudhry, Baredes, Liu and Eloy17 This result is normal. The academic title increases with experience and scientific background. As expected, scientists with higher academic titles had higher h-index scores. However, no significant differences in h-index scores were noted between the professors and the academicians in terms of management positions. These mean scores were 15.6 and 16.4, respectively. In our study, we assessed the top 103 academicians with the highest h-index, regardless of their academic title.
In the comparison between specialties, differences in h-index scores were identified. In a local study, the mean scores of anaesthesia, radiology, and otorhinolaryngology and head and neck surgery branches were 12.3, 15.2 and 15.8, respectively.Reference Pagel and Hudetz18–Reference Svider, Mauro, Sanghvi, Setzen, Baredes and Eloy20 The mean h-index scores in orthopaedics, neurosurgery, internal medicine and general surgery branches were 19.4, 20.3, 24.6 and 27.8, respectively.Reference Svider, Mauro, Sanghvi, Setzen, Baredes and Eloy20, Reference Lee, Kraus and Couldwell21 The weakness of these studies is that they were exclusively performed on a national scale. In the current study, the average h-index value of the top 103 scientists according to the Google Scholar h-index ranking of scientists in otorhinolaryngology and head and neck surgery specialty, and its subspecialties and related special branches, was 37.83 ± 11.49. Given that we could not identify any other study of scientists worldwide that used the h-index scores of familiar branches, we could not compare the data of the first 103 otorhinolaryngologists in the world with other branches in terms of the h-index.
The h-index scores of scientists benefiting from research funds have also been investigated. The relationship between the bibliometric scores of academicians and the utilisation of National Institutes of Health funds has also been evaluated. In addition, studies have assessed whether the index scores of academicians benefiting from these funds are higher than those who do not benefit. These studies have been performed in numerous fields, such as neurosurgery, radiology, anaesthesiology, and otorhinolaryngology and head and neck surgery.Reference Venable, Khan, Taylor, Thompson, Michael and Klimo2, Reference Pagel and Hudetz18–Reference Svider, Mauro, Sanghvi, Setzen, Baredes and Eloy20 In all of these studies, academicians benefiting from these funds had higher h-index scores than academicians who did not use these funds. According to a study of 477 scientists from 20 otorhinolaryngology and head and neck surgery departments, 158 scientists who were supported by National Institutes of Health funds had higher h-index scores than the other 319 unsupported scientists.Reference Svider, Mauro, Sanghvi, Setzen, Baredes and Eloy20 From 158 academicians supported by National Institutes of Health funds, 35 had Doctorates of Medicine (MD), 111 had Doctorates of Philosophy (PhD), and 12 had Doctorates of Medicine and of Philosophy (MD/PhD) academic degrees. The average h-index values were 20, 14.8 and 14.6, respectively. A positive contribution to the h-index scores is expected given the potential among scientists who are performing research using various funds to cite every novelty or difference. Surprisingly, the average h-index values of Doctorates of Medicine degree graduates are greater than those with Doctorates of Philosophy and Doctorates of Medicine and of Philosophy degrees. We believe this issue should be assessed in further studies.
• The h-index score is one of the most important bibliometrics to evaluate scientific productivity
• Web of Science and Scopus use the h-index, but Google Scholar has the broadest database
• The h-index scores of the top 100 otorhinolaryngologists were evaluated
• The otorhinolaryngologists’ h-index ranged from 25 to 81 (mean, 37.83 ± 11.49)
Conclusion
The h-index is an objective value that qualitatively and quantitatively assesses the scientific productivity of an academician. This is the first study in which academicians worldwide and working in a specialty were examined based on the Google Scholar h-index score. In the current study, the average h-index score of the top 103 scientists in otorhinolaryngology and head and neck surgery, and its subspecialties and specific fields, ranked according to the h-index values was 37.83. Approximately three-fourths of the scientists working in otorhinolaryngology and head and neck surgery and its sub-branches have an h-index score of 30 or greater. It is not possible to obtain the Google Scholar h-index and citations of scientists who do not have Google Scholar accounts. Thus, only scientists with Google Scholar accounts were included in this study.
The h-index score, which is a generally new metric, has rapidly gained popularity and is currently widely used. We believe that this scoring system will remain important in the future and may represent a critical criterion in hiring scientists who can benefit from scientific funding.
Competing interests
None declared
