Data about scientific activities are increasingly used to map out, evaluate, or govern science. Therefore, we agree with Pandit et al1 that bibliometric analyses performed should follow a strict methodology that must be specified, to the extent possible, in the published works. Following the principles of the Leiden Manifesto (http://www.leidenmanifesto.org. Accessed August 2017), we have proposed that “Data collection and analytical procedures must be open, transparent, and simple” and that “Data and analyses must be open to verification by those evaluated” (Leiden Manifesto principles 4 and 5). In this line, our methodology clearly specifies the data sources (Web of Science and Scopus), the download date, the search strategy, the terms used, and the document types that were considered.2 This is done with the objective of supporting reliability and avoiding misunderstandings.
Our choice of the terms “difficult* airway*” is supported by the universal acceptance of this expression when dealing with this topic, as established in national and international guidelines (in American Society of Anesthesiologists since 1993), scientific societies (such as the Difficult Airway Society), or in numerous publications. In MeSH (PubMed), we can see that the hierarchically superior term of difficult airway (DA) would be “Airway Management,” but this is too generic and broad to download documents about the specific topic DA, as shown by its thematic structure (National Library of Medicine. MeSH Database. Available at: https://www.ncbi.nlm.nih.gov/mesh/68058109. Accessed August 2017).
Moreover, the restriction to “article” and “review” is justified by the desire to analyze homogeneous document types and to avoid mixing in letters, corrections, or proceedings that have a clearly different structure and behavior from the document types used in the work.
Pandit et al1 mention that they have participated in 29 works on DA. Consulting our original database, we found that our numbers are very similar to what they indicate. However, when we limited the search and adjusted it to the criteria of document types stated in the methodology (article and review), we noted that 14 are letters and editorials; therefore, they are excluded from our analysis. Furthermore, we have seen that of Pandit's remaining works, several may be considered related to “Airway Management” or “Airway Control,” but not specifically “difficult.” As we indicated above, our search strategy was deliberately limited to the terms “difficult* airway*” (DA). The absence of these terms in many of Pandit's works in the fields “Topic” (WoS) and “Article Title, Abstract, Keywords” (Scopus) prevents the articles from being found. Therefore, after reviewing our data and contrasting them with his, we have noted that despite having similar values, the results differ once the indications stated in the methodology are applied. Our data are reliable, transparent, consistent with the published methodology, and replicable. Perhaps, direct comparison of the results of analyses performed with different methodologies (and therefore very different results) has led to a misunderstanding with regard to our results, leading Pandit et al to think that we were not valuing their work adequately. This is not the case. We have a great appreciation for their unquestionable contribution to anesthesiology and airway management.
In their letter, Pandit et al1 state that the University of Oxford and Oxford Radcliffe Hospital are, for research purposes, the same institution. Following the procedures for identification of institutions within the field (explained above), we do not speculate with possibilities like that. Instead, as bibliometrists, we limit ourselves to the rigorous analysis of institutions as they appear in the documents analyzed.