Frequently Asked Questions

One of our faculty members was on the old list of Highly Cited Researchers but doesn’t appear in the new list. Shouldn’t she be on the new list?

Not necessarily, although there are many researchers who, in fact, appear on the both the old and new lists. The period of analysis used for the new list is limited to 2002-2012 and our method of identification and selection of highly cited researchers has changed. Thomson Reuters will retain and provide the old list side-by-side with the new list. In any case, once a researcher is designated as Highly Cited by Thomson Reuters, that researcher is always deemed Highly Cited in our view.

You posted a preliminary list of the new highly cited researchers a year ago (2013) for review and comment, and I was on it, but my name does not appear now in the list. What happened?

We apologize for that. The list posted a year ago, as you noted and as we stated, was preliminary. But it was also defective in two ways. First, there was an error in the processing steps used to generate these data, which we identified after the preliminary list was posted. Second, we attempted to use Web of Science categories to define fields (actually subfields), but the assignment of journals (and papers in specific journals) to multiple, rather than single, areas proved problematic. For example, if a paper was published in a journal assigned to three WoS categories, it was difficult to know which to use as a baseline to measure the impact of the paper against others of similar type. That is why we opted instead, to use ESI field categories, in which journals and individual papers are assigned to a single field.

Why does a junior member of our faculty appear on the Highly Cited Researchers 2014 list, but a more senior member does not?

Again, the specific methodology used in generating the new list (see above) can turn up researchers – even so-called junior researchers – who have contributed multiple Highly Cited Papers during 2002-2012, whereas more senior and even more cited scientists may not have been identified because they did not publish as many Highly Cited Papers in this field (as we defined it, see below) during this period. We think the result conforms to what we were trying to achieve – the identification of researchers with substantial contemporary impact as measured by the number of Highly Cited Papers produced, even if those papers, in terms of total citations, do not sum to more than that of other researchers who have longer publication and higher citation records over their entire careers.

I have been named a Highly Cited author in Engineering but my field and departmental affiliation is actually Mathematics. Would you change my designation to Mathematics?

We understand that you identify yourself as a mathematician, but we found your greatest impact, according to our analysis, to be in Engineering as it is defined in ESI. There is no universally agreed field classification scheme, and the use of journals to define fields is approximate at best. The practical advantage of our method is that we can fairly compare individuals against one another in the same consistently defined sphere.

I have a very common name, and some other people with the same name form (surname and initials) actually work in the same field that I do. How did you make sure not to confuse me and my papers with others and their papers in your analysis?

Ensuring correct attribution of papers to authors involved a manual inspection of each Highly Cited Paper. The Highly Cited Papers in an ESI field for a specific name and its variants (such as, for example, surname plus one initial or two) were ordered in chronological sequence, the subject of the papers examined as well as the journals in which they were published, the institutional addresses reviewed, and the co-authorships inspected. Often this was sufficient to resolve questions of authorship for a unique individual. Original papers were sometimes consulted to obtain a full name not present in the Web of Science bibliographic record (papers indexed before 2006). Reference was made to websites of researchers themselves and their curricula vitae if questions remained, which sometimes arose when a researcher changed institutional affiliations several times during the period surveyed. We would like to think our efforts to resolve authorship questions resulted in 100% clean data, but with any such effort, and more than 3,000 researchers, we likely fell short in some few specific instances and will make adjustments where required.

You say you selected top researchers according to specific fields as defined in ESI. But what about researchers who have Highly Cited Papers across several fields, such as Molecular Biology and Genetics, Clinical Medicine, and Psychiatry/Psychology? How did you account for such cross-disciplinary impact?

We analyzed each ESI field seperately. If we had attempted to identify researchers across fields we would have faced the problem of determining a cross-field baseline for inclusion in an all-field list. In other words, the percentage of Highly Cited Papers required for inclusion differs across fields. In some fields, the number of Highly Cited Papers required for selection was low compared to others – as much as five to one – and each individual would present a different mix of fields in which they published their Highly Cited Papers and in different quantities, thereby creating an unmanageable number of combinations by which to calculate a baseline for inclusion.

Did you apportion credit for Highly Cited Papers according to the number of authors on a paper? You know, in some fields and especially with some highly cited reports (high-energy physics, for example), papers reflect the work of large teams.

You raise the issue of whole vs. fractional counting, which has been likened to measuring participation versus contribution, respectively. The question is a good one but the solution to apportioning credit is not straightforward, and it highlights deep questions about the contemporary meaning of authorship. First, we should recognize that scientists themselves do not explicitly apportion credit on their papers, although there has been discussion about making individual contributions more transparent on papers. The norm – and appearance – is that each author contributed significantly to the publication. How much is left opaque. Let us postulate that fractional credit is better than full credit for each author, i.e., whole counting. In this case a paper with five authors would yield .2 of a paper for each. But, in the absence of specific information on contribution, is not fractional counting just as arbitrary a choice as whole counting? There is more. What does one then do with the citation counts to the paper with respect to each author? Should the total citation count, too, be divided proportionally among the authors? This is an even more perplexing question, calling into question whether contribution may be partial but influence whole. There seems to be a qualitative difference between credit for contribution and credit for impact. Finally, what would appear to be fairer in terms of assigning credit using fractional counting may in fact bias an analysis against papers resulting from teamwork, since some fields, such as mathematics, typically exhibit a very low average number of authors in comparison to, say, biomedical fields. Fractionating credit may undercount contributions from team members and overcount contributions in fields that typically show many single-author publications.

Despite discounting the superiority of fractional counting of publications over whole counting above, we must here comment on an exceptional procedure used in the treatment of Highly Cited Papers in Physics and the selection of Highly Cited Researchers in Physics, 2002-2012. The rise of papers with hundreds and even thousands of authors is a fairly recent phenomenon, one that reveals important changes in the scale of collaboration required in certain realms (see: Multiauthor Papers: Onward and Upward) . High-energy physics is one such area, and others that may be cited are large-scale clinical trials, genome mapping studies, and astronomy projects and related space-based deployments of new instrumentation. But the phenomenon is particularly acute in high-energy physics and evident on many Highly Cited Papers of recent vintage, such as those of the CMS and ATLAS teams at CERN. A preliminary analysis of Physics, using the methodology described above, resulted in a list that included high-energy physicists only, most of whom achieved their ranking through vanishingly small fractional credits. This outcome, and its effect of suppressing all else in physics, required a different approach. In the case of Physics – and Physics only – we removed from our analysis any paper with 30 or more institutional addresses (n = 436 out of 10,373), and this eliminated the problem of dealing with high-energy physics papers exhibiting ‘a cast of thousands.’ The use of 30 as a threshold for institutional addresses was determined heuristically through examination of all Highly Cited Papers in physics, their content, and the desire to include reports deriving from extensive multi-institute collaborations but not those from huge teams, as found in many high-energy physics experiments. The result was a more balanced view of high-impact researchers and topics in Physics. High-energy physicists, especially theoreticians, nonetheless do appear on the new list. This ‘Gordian-knot’ solution will not please some, but it solved the problem we faced in a practical way.

I believe I have a method that produces a result more consistent with the scientific community’s perception of top researchers in a field. Would you take into account my feedback?

We would appreciate your feedback! Please contact us at Tech Support.

I want to talk to someone at Thomson Reuters in detail about the methods used to generate this new list. How may I do so?

Thank you for your interest in our work. We’d be glad to communicate with you. Please contact us at Tech Support

I am a Highly Cited Researcher; how do I update my primary or secondary affiliation to show my current position?

To update your primary or secondary affiliation please contact us at Tech Support.