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scientific organization that aims to create specific communities of researchers reviewing and recommending, for free, unpublished preprints in their field.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.

Only agree to review manuscripts that you can assess in a timely manner.


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 check that scripts, simulation code, software parameters, etc. are available to the reader (e.g. repository link/DOI or appendix); this is a prerequisite for submission to 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 check for potential plagiarism. All the articles submitted to PCI are checked with the Ithenticate tool.

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

Try to consider both the technical merit and the scientific significance of the preprint.

Provide specific suggestions for improvements.

Evaluation of the different components of the article


Check that the title clearly reflects the content of the article.


Check that the abstract is concise and presents the main findings of the study.


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

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.


If possible, evaluate the consistency of raw data and scripts.

If necessary, 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).

Inform the recommender and the managing board if you suspect scientific misconduct.

Tables and figures

Check that figures and tables are understandable without reference to the main body of the article.

Check that figures and tables have a proper caption.


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.

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

Report any reference cited in the text that does not appear in the reference list.

When you review a revised version of a preprint

Evaluate how the authors addressed your comments.

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

If you disagree with the other reviewer(s) and agree with the authors’ explanation and defense of their original article, help the recommender out by discussing these issues.


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