Review confidentiality vs Collaborator Interest conflict

Question

The prevailing view at Are abstracts confidential during the review process? is that all information in the review process is considered confidential, including the information sent to you before you agree (authors, title, abstract).

Two days ago, a collaborator sent me an interesting project proposal which I thought was a really good idea. Yesterday, I received a request to review a paper (from a different group) that seems to have done pretty much the same thing.

I don't want my collaborators to waste time doing something already done. I also don't want to break confidentiality by telling the collaborators one of the leading groups in the field has already done the thing. What would be the 'correct' thing to do here? I have accepted the review because it's within my area of expertise, but I don't know what, if anything, I can tell my collaborator about the fact that their idea has already been done in a paper I'm reviewing.

Answer 1

I don't think it would be unethical to tell them that what they propose is very close to a paper currently under review. Suggest they wait before spending too much effort.

Don't give details, even if pressed. You don't need to say you are the reviewer and especially details about the paper. All you reveal is the existence of such a work.

This doesn't seem to break the rules at Nature as given in an answer to the linked question.

You could finesse it also, by saying you think it better to wait a bit before pursuing that - giving even less information.

You could also, of course, seek some advice from the editor.