Peer Community In

“Peer Community in” (PCI) is a non-profit scientific organization that aims to create specific communities of researchers reviewing and recommending, for free, unpublished preprints in their field.

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The network image was drawn by Martin Grandjean: A force-based network visualization - CC BY-SA.

PCI Reviewer Guide

Reviewing an article submitted to a PCI is very similar to reviewing for a journal with one difference: contrary to what happens in most journals, the review history will be published by PCI if the article is accepted. (At PCI C Neuro, possibly also if the article is not accepted.)

Here, we provide guidelines for reviewers, which are derived from other services and organizations cited below. 


General advice

Be constructive, kind and respectful.

Be precise and clear.

Remain open to new approaches.·     

If you lack expertise on certain points, state it in your review.


What you should NOT DO

 You should not have a conflict of interest with the authors or with the content of the article (cf If you have a conflict of interest, you must decline the invitation. 

No need to examine whether the article falls within the scope of the PCI. Once a submission has been validated by the managing board, it is considered suitable for that PCI.

No need to comment extensively on typos, spelling and grammar (but you can if you want). If language is poor, just mention it, and suggest that a native English speaker read and correct the article.

No need to make recommendations about acceptance or rejection – this is the role of the recommender (the equivalent of an associate editor at a traditional journal) handling this preprint.

No need to check the format of references (but you can if you want).

Don’t discredit negative results.

Don’t ask for new experiments if the study is already well performed and the conclusions clear enough. You can suggest that authors perform further experiments, but only if they are really necessary in order to boost confidence in the interpretation of the results.

Avoid unconstructive, ambiguous, and unsupported comments.

What you should DO

In general

Promptly accept or decline invitations to keep the time to decision short.

Try to keep to the deadline: it shows respect towards the authors. Post your review within three weeks after accepting the invitation. In case of anticipated delays, please inform the PCI recommender and managers.

Check carefully that you do not have any conflict of interest with the content or with the authors of the article. If so, you must not review the article. If you are unsure whether or not you have a conflict of interest, ask the PCI managers by writing them an email at

Provide a detailed, objective report on the merits of the preprint.

Identify flaws (if any) in the design of the research, and in the analysis and interpretation of results.

Expose your concerns (if any) about ethics or scientific misconduct.

State the preprint’s strengths as well as the weaknesses.

If there is something critically missing, report it

Provide specific suggestions for improvements.


Check that the introduction clearly explains the motivation for the study.

Check that the research question/hypothesis/prediction is clearly presented.

Check that the introduction builds on relevant recent and past research performed in the field.

Materials and methods

Check that scripts, simulation code, software parameters, etc. are available to the reader (e.g. repository link/DOI or appendix).

More generally, check that sufficient details are provided for the methods and analysis to allow replication by other researchers.

Check that the statistical analyses are appropriate.


Check that raw data are available to the reader.

Check that all tables, figures, data, and any supplementary documents referred to in the text exist and are available to the reader (e.g. repository link/DOI of) or appendix).

If needed, and if you can, run the data transformations and statistical analyses and check that you get the same results.

In the case of negative results, check that there is a statistical power analysis (or an adequate Bayesian analysis).


Check that all references are appropriate and that necessary references are present.


Check that the conclusions are adequately supported by the results and that the interpretation of the analysis is not overstated.

Check that the discussion takes account of relevant recent and past research performed in the field.

When you review a revised version of a preprint

Evaluate how the authors addressed your comments.

If you have new requests of modification, please state them clearly. But in general, try not to start new lines of interrogation if the previous points were addressed adequately.


Fossils and shit: so you want to do a peer review

Plos: how to write a peer review

EASE: how to serve as an effective referee