How to Write Peer Review Comments: Guide & Examples
Writing peer review comments is an essential academic skill, but even experienced researchers can find it challenging to communicate criticism clearly and professionally. Reviewers must identify meaningful weaknesses, recognize research strengths, and suggest improvements without making their feedback vague, overly harsh, or unnecessarily demanding.
If you are learning how to write peer review comments, the most effective approach is to explain what the issue is, why it matters, and what the authors can reasonably do to address it.
A useful review should help authors improve their manuscripts while providing journal editors with an informed evaluation of research quality.
This guide explains how to organize reviewer comments, write constructive criticism, distinguish major and minor revisions, and communicate recommendations for scientific and academic research papers.
What Are Peer Review Comments?
Peer review comments are written observations and recommendations provided by reviewers after evaluating a research manuscript.
In academic publishing, journal editors invite subject-matter experts to examine submitted papers and assess their originality, methodology, findings, and scientific contribution.
Reviewers communicate their evaluation through comments that highlight strengths, identify problems, and recommend possible improvements.
Comments may address significant research issues, such as inappropriate statistical analysis, or smaller presentation concerns, such as unclear tables.
According to Wiley's reviewer guidance, constructive, organized feedback helps authors respond effectively and supports editorial decision-making.
The purpose of reviewer comments is not to rewrite a manuscript or criticize its authors. It is to provide an independent, evidence-based assessment of the work.
How to Write Peer Review Comments: 7 Essential Steps
Writing a professional review becomes easier when you follow a systematic approach rather than recording disconnected criticisms.
Step 1: Read the Manuscript Before Writing Comments
Begin by reading the complete research paper to understand its objectives, methodology, main findings, and conclusions.
Avoid forming a final judgment based only on the abstract or introduction.
During the first reading, identify the study's overall contribution and note any questions about its scientific validity.
During a second reading, examine the methodology, data analysis, and interpretation more carefully.
Record the manuscript sections, figures, tables, or line numbers associated with your concerns.
These references will help authors locate the issues you identify.
Step 2: Start With a Brief Summary
A professional reviewer report normally begins with a short explanation of the manuscript's research question and contribution.
This demonstrates that you understand the work and gives context for your subsequent comments.
For example:
"The manuscript investigates the relationship between renewable energy integration and electricity grid stability. The topic is relevant to current energy systems research, and the study presents several potentially useful observations."
Keep the summary objective. Avoid repeating the entire abstract or describing every result.
Step 3: Identify the Manuscript's Main Strengths
Before discussing weaknesses, recognize meaningful strengths supported by the paper.
These might include an important research question, a suitable methodology, a valuable dataset, or a clear presentation of findings.
For example:
"The study addresses a relevant research gap, and the experimental design is generally appropriate for the stated objectives."
Positive feedback should be specific and proportionate.
Do not exaggerate a manuscript's strengths if it contains fundamental problems affecting the validity of its conclusions.
Step 4: Separate Major and Minor Concerns
Organize your observations according to their importance.
Major concerns involve problems affecting scientific validity, methodology, essential evidence, or interpretation.
Minor concerns generally involve reporting clarity, terminology, presentation, and correctable inconsistencies.
For instance, missing information about participant recruitment may be a major concern if it prevents readers from assessing selection bias.
A mislabeled figure may be a minor issue when the correct interpretation remains clear.
This distinction helps authors prioritize revisions.
Step 5: Make Every Comment Specific and Actionable
Avoid generic criticism such as "The methodology is unclear."
Instead, explain the issue and identify the information needed.
For example:
"The methods section does not explain how participants were allocated to the study groups. Please describe the allocation procedure and clarify whether randomization was used."
Specific comments are easier for authors to interpret and address.
Where possible, explain how the problem affects the study rather than simply requesting additional information.
Step 6: Use Respectful and Objective Language
Reviewers can be critical without using negative or personal language.
Focus on what is presented in the manuscript rather than making judgments about the authors' abilities or intentions.
Instead of writing, "The authors do not understand the statistical analysis," write:
"The statistical approach requires additional justification, particularly regarding the assumptions underlying the selected model."
Neutral wording makes criticism more professional without reducing its scientific rigor.
Step 7: Review Your Comments Before Submission
After drafting your feedback, read the report again.
Check whether the comments are accurate, sufficiently explained, and consistent with your overall assessment.
Remove duplicated concerns and combine closely related observations.
Make sure significant methodological issues are not buried beneath numerous grammar corrections.
Finally, confirm that your comments comply with the journal's reviewer instructions and confidentiality policies.
A Simple Formula for Writing Constructive Peer Review Comments
A practical way to improve reviewer feedback is to use a three-part structure:
Issue + Significance + Suggested Action
This framework helps transform general criticism into a useful recommendation.
1. Identify the Issue
Describe the specific problem in the manuscript.
Example:
"The study does not explain how the sample size was determined."
2. Explain Its Significance
State why the concern matters for the research.
Example:
"Without this information, it is difficult to assess whether the sample provides sufficient precision for the reported estimates."
3. Suggest an Appropriate Action
Recommend a reasonable clarification or correction.
Example:
"Please describe the sample size justification and discuss any relevant limitations."
Complete Reviewer Comment
"The manuscript does not explain how the sample size was determined. This makes it difficult to assess the precision of the reported estimates. Please provide an appropriate justification and discuss any resulting limitations."
This approach can be used for methodology, statistical analysis, literature reviews, conclusions, and reporting concerns.
Not every issue requires additional experiments. Sometimes clearer reporting or more cautious interpretation is the appropriate response.
How to Write Major Peer Review Comments
Major comments should identify weaknesses that substantially affect research quality or the credibility of the conclusions.
These concerns usually require more than minor editing.
Major Comment on Research Methodology
"The study design is not sufficiently described to determine whether it appropriately addresses the research question. Please clarify the allocation procedures, comparison groups, and measures used to minimize bias."
Major Comment on Statistical Analysis
"The manuscript uses multiple statistical comparisons without explaining how the potential for false-positive findings was addressed. Please justify the analytical approach and discuss its implications for the interpretation of the results."
Major Comment on Research Validity
"The manuscript's conclusions depend on a relationship between two variables, but important potential confounding factors are not considered. Please clarify how these factors were addressed or revise the interpretation accordingly."
Major Comment on Literature Review
"The literature review does not adequately examine relevant studies reporting conflicting findings. A more balanced synthesis would help establish the contribution and limitations of the present research."
Major Comment on Unsupported Conclusions
"The conclusion makes causal claims that are not sufficiently supported by the observational research design. Please distinguish associations from causal relationships and align the conclusions with the available evidence."
These examples illustrate how to identify meaningful concerns without making personal criticisms.
How to Write Minor Peer Review Comments
Minor comments generally address issues that can be corrected without substantially changing the research findings.
They should be concise, precise, and easy to locate.
Minor Comment on Terminology
"Please define the abbreviation at its first occurrence and use it consistently throughout the manuscript."
Minor Comment on Figures
"The labels in Figure 3 are difficult to read. Please increase their size and ensure the measurement units are clearly indicated."
Minor Comment on Tables
"Table 2 contains inconsistent decimal formatting. Please standardize the reported values for clarity."
Minor Comment on References
"Please review the references for consistency with the journal's required citation style."
Minor Comment on Writing Clarity
"The second paragraph of the discussion includes several lengthy sentences. Consider revising them to clarify the relationship between the findings."
Even minor feedback should remain relevant to the manuscript's readability and reporting quality.
How to Write Peer Review Comments for Different Research Sections
Different sections of a research paper require different types of evaluation.
| Manuscript section | Main evaluation focus | Suggested comment opening |
|---|---|---|
| Abstract | Accurate summary of methods and findings | "The abstract would benefit from clarification of..." |
| Introduction | Research question and rationale | "Please explain more clearly how this study addresses..." |
| Literature review | Relevant and balanced evidence | "The literature review should consider..." |
| Methodology | Study design and reproducibility | "The methods section requires additional detail regarding..." |
| Results | Accuracy and clarity | "Please clarify the reported values in..." |
| Discussion | Interpretation and limitations | "The discussion appears to overstate..." |
| Conclusion | Evidence-based claims | "The conclusion should be revised to reflect..." |
Always adapt the wording to the specific manuscript.
For example, qualitative studies require attention to analytical transparency, participant selection, reflexivity, and the relationship between evidence and interpretation.
Quantitative studies may require closer examination of statistical assumptions, effect sizes, uncertainty estimates, and potential confounding.
How to Write Comments to Authors vs. Confidential Comments to Editors
Journal review systems often separate comments intended for authors from confidential communications to editors.
Understanding the difference is important.
Comments to Authors
This section contains the substantive evaluation that authors need to understand and respond to.
It should include the manuscript's strengths, major concerns, minor comments, and specific recommendations.
For example:
"The results section does not report confidence intervals for the primary estimates. Please include appropriate measures of uncertainty and discuss their implications."
Confidential Comments to the Editor
This section is intended for issues requiring private editorial attention.
It may include potential conflicts of interest, suspected research integrity problems, or explanations of concerns that require editorial handling.
For example:
"I noticed substantial similarities between the submitted manuscript and a previously published article. I have not independently determined whether this represents inappropriate duplication, but I recommend that the editor examine the overlap."
Avoid making definitive allegations without evidence.
Do not use confidential comments to communicate serious criticisms that authors need to address while giving them an inaccurately positive review.
Some journals also request that publication recommendations be entered separately rather than included in comments to authors.
How to Write Peer Review Comments for Major Revisions
When substantial changes are necessary, reviewers should prioritize the issues that must be resolved before the manuscript can be evaluated again.
For example:
"The manuscript addresses an important research question, but several methodological concerns require substantial clarification. In particular, the sampling procedure, measurement validity, and analytical approach need additional explanation. Addressing these issues is necessary to assess the reliability of the conclusions."
Follow this overview with separate, numbered comments.
Do not demand additional experiments merely to expand the study beyond its original objectives.
If the available evidence cannot support the principal claims, explain that limitation directly.
How to Write Peer Review Comments for Minor Revisions
Minor revision comments should focus on clearly defined improvements without exaggerating their significance.
For example:
"The manuscript presents a coherent analysis and generally supports its conclusions. A few reporting and presentation issues remain, including clarification of the data source, improvement of figure labels, and correction of inconsistent terminology."
Minor comments should be sufficiently specific that authors can respond efficiently.
A minor revision recommendation should not conceal substantial methodological problems.
How to Write Peer Review Comments When Recommending Rejection
A rejection recommendation requires professional and transparent reasoning.
Reviewers should identify whether the manuscript contains fundamental problems that cannot reasonably be addressed through ordinary revision.
For example:
"The research question is relevant, but the study design does not provide sufficient evidence to support the principal conclusion. The absence of a suitable comparison group and inadequate outcome measurements substantially limit the validity of the findings. These concerns appear to require a redesigned investigation rather than clarification of the existing manuscript."
Focus on the evidence and the study's limitations, not the authors' competence.
The editor remains responsible for the final publication decision.
How to Improve Weak Peer Review Comments
Many ineffective reviewer comments can be improved by adding specificity and scientific reasoning.
| Weak comment | Improved reviewer comment |
|---|---|
| "The introduction is poor." | "The introduction should clarify the specific research gap and explain how the study addresses it." |
| "The sample is too small." | "Please justify the sample size and discuss how it affects the precision and interpretation of the findings." |
| "The statistics are wrong." | "Please explain the choice of statistical test and confirm whether its assumptions were evaluated." |
| "The discussion is confusing." | "Please reorganize the discussion around the primary findings and distinguish evidence from speculation." |
| "The paper needs more references." | "Please discuss relevant studies that directly address the research question and offer competing explanations." |
| "The conclusion is exaggerated." | "The conclusion should be narrowed to reflect the study design and strength of the available evidence." |
The improved examples explain what needs attention without relying on vague or dismissive judgments.
Common Mistakes to Avoid When Writing Reviewer Comments
Even technically knowledgeable reviewers can produce unhelpful reports.
Common mistakes include focusing excessively on grammar while overlooking scientific validity, making unsupported criticisms, and requesting unnecessary experiments.
Other problems include:
- Repeating the same concern in multiple comments.
- Using vague statements without identifying specific evidence.
- Recommending rejection without explaining fundamental weaknesses.
- Making comments about authors' identities or assumed capabilities.
- Requesting irrelevant citations to increase citation counts.
- Including conflicting assessments in comments to authors and editors.
- Sharing confidential manuscripts without authorization.
The Committee on Publication Ethics recommends objective, constructive reviews and appropriate disclosure of competing interests.
Reviewers must also follow the journal's policies regarding artificial intelligence tools. Confidential manuscript material should not be uploaded to external services unless the publisher explicitly permits the intended use.
Frequently Asked Questions About Writing Peer Review Comments
How do you start peer review comments?
Begin with a brief, neutral summary of the manuscript's research question, methods, and main contribution. Then provide an overall assessment before presenting major and minor concerns.
What are examples of good reviewer comments?
Good reviewer comments identify specific issues and explain their significance. For example: "Please clarify the participant recruitment procedure and discuss how the selected sampling method affects the generalizability of the findings."
How do you write constructive criticism in peer review?
Describe the issue, explain why it matters, and suggest an appropriate improvement. Use respectful language and support your concerns with evidence from the manuscript.
What should major reviewer comments include?
Major comments should address significant problems involving methodology, research validity, analysis, interpretation, or conclusions. They should explain how those problems affect the manuscript.
How do you write minor reviewer comments?
Minor comments should identify correctable presentation or reporting issues, preferably with references to specific sections, figures, tables, or lines.
Should reviewers recommend acceptance or rejection in their comments?
Follow the journal's instructions. Many review systems collect recommendations separately from comments to authors, and the editor makes the final publication decision.
How long should peer review comments be?
There is no universal word count. Comments should be detailed enough to explain important concerns and provide useful guidance without unnecessary repetition.
Conclusion
Learning how to write peer review comments involves combining careful manuscript evaluation with clear, objective, and constructive communication.
Effective comments identify specific strengths and weaknesses, explain why issues matter, and recommend reasonable improvements.
Separating major and minor concerns, using professional language, and aligning feedback with the journal's requirements makes the review more useful to authors and editors.
Ultimately, strong reviewer comments are not defined by their length or severity. Their value lies in helping researchers improve their work while supporting fair and informed editorial decisions.