collaboration - How are citations used to fairly compare researchers: fewer publications and fewer co-authors versus more publications with many co-authors

As a recently graduated researcher in the field of physics, I am in the early stages of establishing my scientific career, which involves being hired by senior researchers and professors. Much of the likelihood of being hired in a reputable group relies on my publication record and, for good or for bad, on my citation count.

I have always played a significant role in all the papers I have written or coauthored, which justified my inclusion in the list of authors. Thus I feel that I have earned the many or few citations to my papers.

In the context of a competitive mindset in which your quality is often (perhaps unfairly) measured by the number of citations your work has attracted, it has always bothered me how endless author lists from large collaborations boost the citation counts of those people. It is just a matter of common sense to assume that not all of them have significantly contributed to a paper. I am thinking especially about particle-physics collaborations, such as LHC at CERN. As an example, take this highly cited paper with a couple of hundred authors sharing authorship. The same or very similar author lists appear in several other highly cited articles. I am sure most of these are highly capable and competent researchers, some of which are leaders in their field. But did they all really contributed enough to be credited as authors? Another question: how much is enough?

How can one trust the citation count model (whether it’s fair or not) when there are these collaboration-enhanced players in the game?

How much do professors and PIs rely on citation counts in order to make a decision on hiring a researcher?

Answer

A general rule of bibliometrics is that they shouldn't be used to compare people (or projects, or papers, or research projects) across different fields, because publication culture can vary wildly even within disciplines and between closely allied fields. To begin with, the size of the field - the number of papers published per year, for example - has a direct impact on how many citations each paper gets.

Your quandary is an example of this. In certain fields such as high-energy physics, astronomy, or parts of biology, a lot of the science is concentrated in very large collaborations, which produce papers with many citations and many authors. It is indeed unfair to use citation counts to compare such a CV with, say, a mathematician's, since papers there tend to have few authors and, in many specialized fields, be read by very few people indeed, even for high-quality papers.

Whether such bibliometrics are used in practice by hiring committees - well, that obviously depends on the field, the institution, and the specific people involved. If all the applicants are from similar fields then this may not be a huge problem, but the numbers need to be treated with some distance to avoid the problem you point out. If a hiring or review process places a large emphasis on citation counts (or other bibliometrics) for applicants from different fields, then that is indeed a problem.

One final thing you should keep in mind is that applicants with a high-citation-count, large-collaboration paper in their CV are likely to get asked at interview questions like

So, what was your role in this collaboration?

in any case, as part of the interview process.