This, from PNAS reviewing instructions, is actually pretty good:

"The purpose of peer review is not to demonstrate proficiency in identifying flaws."

@Neurograce thanks for sharing. As I found that sentence alone a bit problematic (I get the point, but fear it’ll be more confusing than elucidating to many), I got interested in its context, but couldn’t find it on the pnas website quickly (’ll look more carefully later). Anyway, what matters is that It’s in several websites as this 2001 “Resources for Research Ethics Education” topic page, where it might originate from?

http://research-ethics.org/topics/peer-review/?print

1/2

@Neurograce the full sentence is much clearer and important, I think - last sentence here: “Offer constructive criticism
Reviewers' comments should acknowledge positive aspects of the material under review, assess negative aspects constructively, and indicate clearly the improvements needed. The purpose of peer review is not to demonstrate the reviewer's proficiency in identifying flaws, but to help the authors or candidates identify and resolve weaknesses in their work.”

2/2

@Gontijo I don't know that it is on the PNAS website; may just be in material they send to reviewers. But makes sense that they took it from more general peer review guidelines (though as far as I recall, did not cite them!)
@Neurograce got it, thanks. Also suspected that was the case. About the lack of citation: it wasn’t cited in the few other sites I checked either, but also consider that I didn’t do a thorough enough search to certify that the 2001 post is the original quote. Cheers