First time reviewer here. My purpose as a reviewer is to make recommendations on how the manuscript can be improved, right? In this effort, should I distinguish my solid expert opinion from mere suggestions?
For example, if I see an error, then I believe I should professionally but firmly point it out:
"X is not a valid conclusion because of y. It should be removed."
However, what if the issue is not a clear-cut error but rather a matter that, in my opinion, would strengthen the quality of the manuscript?
Should I use the same firmness? (Option A)
"X should be added because of y."
or distinguish this as an opinion (Option B):
"Perhaps it would be beneficial for X to be added. Consider including x due to y."
As an author on the other side of things, I would appreciate the distinction so that I understand what either needs to be changed in a revision (or needs to be strongly justified why the reviewer was wrong) versus what I can freely disagree with the reviewer about without having to make a strong justification about why I disagree.
This issue is giving me pause because I've rarely or never seen Option B in reviews of my own manuscripts. All comments by reviewers are similar to Option A.
My apologies if my examples are too vague. I tried to make the applicable to the whole community here which requires ambiguity unfortunately.
You have space. If you have a scheme of what to do, just follow it. Read further if you don't have any scheme:
Your purpose as a reviewer is typically NOT to make recommendations on how the manuscript can be improved. You are NOT asked for suggestions how to improve. You are asked for an evaluation. I suggest the following scheme:
X is not a valid conclusion because of y. It is wrong to include x into the paper.
Perhaps it would be beneficial for Z to be added. Consider including Z due to W.
Include "improvement suggestions" only if you really wish to or if you are asked for that explicitly. If in addition you are asked for "nondisclosed comments to the editor / program-committee" or something else, then include such parts, too.