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Assessing an article

Comprehensive peer review training

On this page you can find an overview of how to critique a scientific manuscript and what to look for when acting as a peer reviewer. However, IOP Publishing also offers a free, comprehensive online training course leading to IOP Trusted Reviewer certification.

Our Peer Review Excellence course takes around 90 minutes to complete. You can register for free here: Peer Review Excellence.

When you review a manuscript for any IOP Publishing journal you are eligible for IOP Trusted Reviewer certification.

Our editors rate all of the reviews we receive on a scale of 1-5, with 5 representing a review of outstanding quality. Any reviewer who submits a report rated 5 will achieve IOP Trusted Reviewer status and become eligible for our Reviewer Awards. For reviewers who have completed our Peer Review Excellence training, the threshold for IOP Trusted Reviewer status is a review rated 4 or above.

Please note that in cases where the manuscript editor rescinds a reviewer report due to excessive self-citation, citation manipulation, or any other form of reviewer misconduct, the re-submitted report will receive a maximum rating of 2.

This document shows how we use the 5-point Reviewer score to rate reviews.

These documents contain examples of outstanding reviews in the fields of:

This document contains examples of reviews rated 1, 3, and 5.

What to check for as a journal reviewer

Scientific rigour

  • Is this paper understandable?
  • Is the paper scientifically correct and robust?
  • Are the mathematics or statistics correct?
  • Has the author made reference to the most recent and most appropriate work?
  • Are the scientific arguments and interpretation accurate and consistent with the results presented?


  • What impact do you think this paper will have on the field and surrounding areas?
  • How timely is this paper?
  • Why should this work be published?


  • Is the work relevant and novel?
  • Have any parts of the manuscript been published before?
  • Does it add significantly to results that are already published?
  • Is this paper likely to be cited in future?


Some articles will be required to include an ethical statement if their research involved human or animal subjects. In journals that operate double-anonymous peer review, ethical statements are not revealed to reviewers as they may gives clues to the author’s identity. Our editorial team check all ethical statements are appropriate for the study being reported. If a reviewer feels they need to see an ethical statement, they are advised to contact the journal to discuss.

Please contact us if you suspect any ethical wrongdoing related to the paper, including but not limited to:

  • Plagiarism
  • Self-plagiarism
  • Parallel submission
  • Fabrication of results
  • Undeclared conflict of interest
  • Inaccurate authorship declarations
  • Unnecessary self-citations.

We follow the COPE guidelines on responding to whistleblowers, which includes protecting your anonymity.


  • Is the title adequate and appropriate?
  • Is the paper well written and the work clearly communicated? Please note we will edit upon acceptance and correct any grammatical or typographical errors.
  • Does the abstract contain the essential information about the paper? Is it complete by itself and suitable for direct inclusion in an abstracting service?
  • Can the paper be shortened without detriment to the content? Are the text and mathematics brief but still clear? If you recommend shortening, please suggest what could be omitted.
  • Are diagrams and tables clear and essential, and captions informative?
  • Does the paper contain a carefully written conclusion, summarizing what has been learned and why it is interesting and useful?

What you do not need to check for

Reviewers are not expected to correct spelling, grammar or use-of-English mistakes, as most journals have copy editors who can correct minor problems with the language. However, if the paper is written so poorly that you cannot clearly understand what the authors mean, or there are so many errors that reading the paper becomes very difficult, then that should be reported back to the journal.

Implicit bias in peer review

We all have implicit biases based on our background and experiences. They can cause us to take shortcuts in decision making which can serve us well and save us time, but often they are wrong and end in unfair assessments.

During the peer review process the following biases can influence how you assess a paper and what conclusion you come to:

  • Gender bias
  • Bias for or against authors from a geographical area
  • Language bias, if a paper is translated poorly
  • Bias for or against authors from specific institutions
  • Bias against researchers at the beginning of their research career

We can all address our implicit biases through self-awareness. You can minimise the influence of your implicit biases during the peer review process:

  • Be aware that you have implicit biases that may affect your decision making
  • Treat the paper as if you did not know the authors’ names and institutions
  • Focus on facts rather than feelings
  • Slow down your decision making
  • Consider and reconsider the reasons for your conclusions.
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