Question

what does a reviewer do during peer-review

Answer 1

they are usually called referees now days, basically:

The first one is more like an editor.. they decide if the paper you are submitting is relevant to the journal you are submitting it to. If that person thinks it isn't they reject your paper and tell you why.

The second set (which can be 2 or more, my paper I recently got published ended up having 15) look at your paper first categorically; is the basis correct (is your general idea sound), is it important (why would anyone care), is there any major error in the way you did something, has this been done before.
When those questions are answered (you would want: yes, yes, no, no) then you move on to checking the science. Since we know you did everything correct, did you draw the correct conclusions, could something be added? did you assume too much in your conclusions? Did you adequately discuss limitations or drawbacks to what you did? Did you include figures where they should be? Are they easily understood? Do you need new ones, or fixed ones?

And throughout the process everyone looks for things like grammar, syntax, word usage. The final step is taking into account all your discussions with the referees fixes to the manuscript, etc. to rewrite/fix the paper and submit for final publication.

It is important to note that the reviewers and the writers dont have to agree on most things--the main point of the process is that you can adequately \(\sf defend\) your position to someone else highly regarded in the field. And if you cannot defend a particular position you are able to \(\sf amend\) your position to an acceptable one (for both you and the review pannel).



Lastly, I'd like to note that people with PhD's are used to this type of thing. The last thing you do before being awarded a PhD is the disertation/thesis defense. Which is basically a multi-hour multi-day review of your research that you have done for the last 3+ years against a pannel of professors that were helping you the whole way, that are completely aware of where you made mistakes and point them out to force you to understand your position.