Personal contribution in N-author articles vs single author articles

Question

In a given field there are essentially two types of articles, N-author articles and single author articles. Related to this fact, I wonder how a committee when evaluating someone for a tenure promotion establishes the personal contribution of an N-authors article? Just to give an example, suppose that we have two candidates which one has in total 20 articles, all co-authored, and another candidate which has in total 15 articles, with only two co-authored articles, and the rest are single authored. Assume also that both candidates have published their work in the best journals in their working field.

Based on your experience and on my example above, how is in reality determined the PERSONAL contribution of an N-authors article? Would this contribution just be 1/N? Which of the candidates in the example which described above would be more likely to be selected for a promotion? How in reality are seen single author articles published in the best journals in a given working field?

An observation: Usually people who work with several co-authors tend to have more publications than someone who works alone. Also in many fields, in an N-authors article, the author names are put in alphabetic order.

EDIT NR.1: My question is mostly related to theoretical fields, such as mathematics, theoretical physics and computer science. In these fields usually the number of co-authors is N<10.

Answer 1

There isn’t a precise rule about such things, but to the extent that one can formulate a general principle, I’d say that the credit for an N-author article would almost always be greater - often significantly greater - than a 1/N fraction of the total credit. That is why collaboration is generally a profitable activity - it allows two or more people to leverage their skills and abilities and together create something that is worth more than the sum of its parts: the very definition of synergy.

Another synergistic effect in collaborations is that your coauthors will be going around giving talks and telling people about your joint paper. If effect, you get double (or five, or ten times) the “marketing” or “buzz” about your paper for the same effort on your part: the credit you get is higher simply by virtue of more people getting to hear about your paper. Moreover, when your coauthors give talks about your paper they can say flattering things about you that you probably wouldn’t dare to say about yourself, or that if you did say about yourself people wouldn’t be as impressed by (and it works both ways, you say nice things about your coauthors’ contributions when you give talks about the joint papers of course).

I estimate that close to half of my papers are solely authored, and the others are joint. I enjoy both styles of work, although I think these days I most enjoy the freedom that comes with writing papers by myself. I often reflect about the (small) injustice that comes with the fact that those papers usually take longer to make a splash than my jointly authored ones, for the reasons I mentioned above. Oh well. Not every decision we make is driven by some ultra-rational cost-benefit analysis. Do what makes you happy, and what you feel you are good at. Some people excel at collaborating, others are solitary thinkers.

My experience is with pure mathematics, and applies mostly to papers with 1-4 authors. In math, for papers where the number of authors is, say, 6-10 (which are quite a rarity), the credit might start getting seriously diluted, to the point that I’m not sure how much of what I wrote above is accurate - probably it would depend quite a lot on the specific details of who the authors are and what their paper is about.

Answer 2

This depends on the type of evaluation the committee is doing.

In a "gross" evaluation, such as an evaluation done by non-specialists, or at the stage where a committe selects 30 out of 150 applications, the difference between single-authored and multi-authored papers can get lost in the noise. In particular this will happen if people use coarse bibliometric indicators such as the h-index.

In a "fine" evaluation comparing a few candidates on a shortlist, there is more time for actually reading papers, and single-authored papers can become disproportionately influential because there is no question of who did what.

Answer 3

That depends on your field.

In my field (bioinformatics / biomedicine) co-authorships have almost no value (because being author number 12 out of 23 is not much of an achievement). What really counts is if you are first author (=first position) or senior author (=last position). But authoring a paper alone looks also a bit odd as you might look like a weirdo/loner (but in other fields like math this is more common).

Answer 4

You equate theoretical physics with math/comp sci in this question. But a major difference that I am used to from physics (all of it) to math is first author emphasis versus alphabetical author list. If you are looking at a field where first author prominence is acknowledged, then there's nothing to worry about with adding more "bodies on the sleigh" (assuming you are first). If it's not, then you have more concern and should try to do sole-author papers.

Answer 5

Based on your experience and on my example above, how is in reality determined the PERSONAL contribution of an N-authors article?

The correct answer is that you should not try to quantify or judge performance based on authorship alone. Additional, qualitative information is always important. You must know what was in the publication, and how the publication has been used.

In practice, I recommend asking the authors to explain their individual contributions.

Answer 6

As mentioned above, it depends. First authorships matter, last authorships matter, solo authorships matter, authorships without your supervisor / mentor / head of department matter, impact factors matter. I've even seen mentions of a points system, where each publication was awarded some number of points and you need to have so and so many to pass your habilitation (which is something like a tenure evaluation in Germany).

So, what can be recommended? Try both. Being on a huge paper in a highly praised journal, even if it's a collaborative effort with 100 people, will do you some good. Publishing a paper completely on your own, even if the target journal is less well ranked, will do you good. How much good it is, depends on your area.

Some journals, esp. in biomed area, have a thing called author contribution list, where is stated who did what. Similar statements are sometimes required for all of your publications by some hiring committees.