Why are there so many co-authored papers?

A loyal MR reader asks:

I’m reading (grr) a lot of academic papers lately and, to keep myself awake, have wondered: why do they almost always have more than one author? Is it like cops in New York City–they’ve got everyone persuaded it’s too dangerous to go alone? Is there some networking benefit, professional or psychological? Does it just enable everyone to claim more publications? Has anyone studied which fields have the highest and lowest average number of authors per paper?

I thought you could blog something interesting on this. I might add that the papers couldn’t be any duller, and I wonder if committee authorship plays a role in this as well.

I believe that co-authored papers are correlated with:

1. The existence of a laboratory

2. Senior scholars who generate funding and thus gains from trade

3. Empirical work, which tends to be more divisible than theory; co-authored papers are relatively rare in pure economic theory and in philosophy

Co-authored papers are becoming increasingly common in economics, also because the effort requirements for top publications have been rising.  In most cases a co-authored piece is worth at least 2/3 of a singly-authored piece, so the incentives for co-authorship are strong.  Here is an earlier post on co-authorship.


#2 reminds me of popular novelist James Patterson, who has been releasing a stream of co-authored books lately. Some cynics wonder if he has written much more than his name on the cover and the check endorsements.

A. Smith suggests: "The division of labour, however, so far as it can be introduced, occasions, in every art, a proportionable increase of the productive powers of labour."

In my experience, single authorship is the norm in the humanities. Sociology has less co-authored papers than economics and psychology, which in turn have less than the natural sciences, where single authorship is rare.

All of which fits nicely with your hypotheses above.

"In most cases a co-authored piece is worth at least 2/3 of a singly-authored piece, so the incentives for co-authorship are strong."

Is there some objective valuation behind this statement?

Don't forget the grad student - advisor dynamic.

from my experience, it is both more fun and a better way of learning to discuss your ideas with a colleague (who may give you a different perspective) and look for solutions together. Hence, I prefer to co-author my papers.

Laboratory and empirical work both imply you looking for a "right" answer, so if you make a mistake your result will likely be proved wrong at some later date. Two or more people working together are less likely to make embarrassing mistakes.

Outside the halls of academia it may be seen by some companies as a way to increase the worth of their employees in the eyes of the client and to provide an instant patina of expertise.

Multiple authorship is not a new phenomenon, although the increases in the number of co-authors is somewhat amazing (and apparently also a possible source of research fraud, but that's another story). It does have a lot to do with the sociology of the particular discipline. Isaac Asimov tells the story in the first volume of his autobiography of working really hard one summer to complete the research for, and write, a paper for a chemistry journal, which was, in fact, published. And for which he caught a lot of flak from his colleagues--single-authoring was just not the way things were done. In, as I recall, 1948 or so. In chemistry.

By "co-authored," I presume you mean 2 P.I.s?

As in, not "co-authored" as in the graduate student who did all the work and his advisor, right?

"And for which he caught a lot of flak from his colleagues--single-authoring was just not the way things were done"

Single authorship might imply being hard to work with. But a single instance of it is hardly a trend. Cooperation can be good, not always, and should be used on its merits, not encouraged beyond its benefits. Solitude can be good, too. The right tool for the job should be found over time through experience, not heavy-handed arbitrary incentivization.

It annoys me when people make virtues of necessity and vice versa.

Might "fun" and "ease" have anything to do with it? At least in some cases?

FWIW, I've co-authored some long-form fiction, and I loved the process: No loneliness, both of you jogging each other out of delusions and mopes ... Loads of fun.

In fact given what a drag it can be to sit alone for months in front of a keyboard, I'm amazed that more people don't co-author long-form fiction. That does depend on personality and chemistry, of course.

The simplest explanation: papers with multiple authors are higher quality and so are accepted more often. This isn't too hard to believe, since each author can focus on different aspects of the work, and more eyes means more bugs and errors are found. I agree with previous comments that there is a division of labor advantage going on.

In computer science I would say the norm is 1-4 authors per paper. The best papers tend to have 2-3 authors. Single author papers can be good, but often lack polish or completeness.

Positive externalities of human capital. And a more competitive research environment (the internet has leveled the playing field.)

As Lucas remarked in his "Mechanics of Economic Growth" article, this is why the better the department, the more rabid (slight paraphrase here) they are about recruiting the best new doctoral grads.

At least in the physical and life sciences, virtually all areas of significant research require significant interdisciplinary or inter-specialty collaboration. It should hardly be surprising there are so many multiple-author papers. This is true even at primarily undergraduate institutions. A happy by-product of collaboration is the everyone can share the wealth--it's really not so much about dispersing the responsibility.

On the costs side - the internet has lowered the transactions cost of collaborating.

I think I've got it! Since putting 10 economists in a room typically yields 11 different opinions, this is a concerted effort - even if unwittingly - to bring those #s into alignment ;)

thank you for this information

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