Conflict of interests and the assignment of referee for a very narrow field

Question

Consider a very small scientific field with three major contributors and a total of 15 authors, all of them had coauthored with everyone else.

In this field how could the editor choose referee for new papers, if he must adhere to the conflict of interests policies?

I know that some editors handle coauthor/students' paper or assign the paper to the previous coauthor of the author. Is that a common practice for a small field?

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The small field was naturally extended from some important results back to 50s -70s, some of those researchers are still alive, but inactive. The importance cannot be doubt by the larger field, also because of those important results historically.

Answer 1

It's hard to believe a field can be completely cut off from the rest of the world and have only 15 active contributors. Even the pariah field of cold fusion has some 100-200 researchers. Granted because cold fusion is such a small field, even 100-200 active researchers might not suffice to find reviewers who have never worked with each other. It's also a polarized field where much of the rest of the world believes the 100-200 people still working on it are wasting their time.

That said, one can still find reviewers. I know one editor which implemented a 1-1 system: each paper would be reviewed by one person in the field and one person outside the field. As a concrete example, a theoretical paper on cold fusion can likely be critiqued by someone who knows Quantum Field Theory (which is much broader and largely independent of cold fusion).

Of course there's a bias here that you'll likely get one "accept" review and one "reject" review. The editor is aware of that however, and will take it into account.

Answer 2

Even if the field is small, one can usually find referees in cognate fields with no conflicts: presumably papers by these groups have a bibliography that extends beyond these groups, else the interest is overly narrow and the paper can be rejected as such.

(Aside: the handling editor is not necessarily a “he”.)