Principles of peer review
Frontiers upholds strict quality standards for manuscripts and the peer review process through clear criteria and dedicated teams. Manuscripts that pass these criteria are accepted, those that do not pass the criteria are rejected.
We don't reject manuscripts based on their perceived potential impact, nor do we set a rejection rate – formal or informal. Instead, we judge the value and validity of presented work through rigorous quality checks and empower our editorial boards to take charge of content decisions.
Handling editors and reviewers can recommend rejection at any time; editors make acceptance decisions; and chief editors make acceptance and rejection decisions. Frontiers' in-house research integrity team performs pre- and post-review quality screens and can reject articles that do not meet acceptance criteria (listed below). This model ensures rigorous peer review, rapid decisions, and the publication of high-quality research.
What is expected of everyone involved?
Authors must submit a manuscript that has significant scholarly value and falls within the scope of the journal. They must comply with all editorial and ethical policies and take all reviewer and editor comments into consideration.
Reviewers are subject experts and evaluate manuscripts by using the quality assessment tool and designated review questionnaire that prioritize scientific quality, rigor, and validity. They evaluate the methodology of a study for solidity and rigor, and ensure the research provides valid conclusions and is supported by sufficient data.
Editors are subject experts and assess the peer-review process and manuscripts meticulously. They only endorse publication if the reviewers validate the contents of a manuscript.
Chief editors, handling editors, reviewers, and authors are guided and supported by our peer review team, which upholds and ensures high quality standards for manuscripts and the peer review itself, certifying the quality, scientific rigor, and validity of research articles and promoting collaboration among authors, reviewers, and editors.
If an editor, reviewer, or author is in doubt on how to proceed during the peer-review process, the peer review team is the main point of contact for guidance, with two specialized sub-teams: research integrity and editorial review operations.
Manuscript quality standards
Our research integrity team ensures that manuscripts adhere to high quality research and ethical standards and prevents the publication of any manuscripts that are below our quality standards.
At any stage before official publication, if a manuscript does not meet our editorial criteria and standards for publication, or if peer-review or research integrity concerns are raised by any review participant or reader (abstracts are published online ahead of official publication), the journal's chief editors and Frontiers' Chief Executive Editor will investigate these concerns, regardless of peer review or acceptance stage.
Frontiers applies the following criteria for acceptance and rejection of manuscripts. See further information on our editorial and ethical policies below, as well as in our author guidelines, Frontiers policies and publication ethics, and terms and conditions.
Acceptance criteria
All submissions accepted at Frontiers must be VALID:
Valid research question and hypothesis, with a relevant theory to which the research question is being posed
Applies correct and transparent methodology, and the study design and materials are clearly laid out
Language and presentation are clear and adequate, figures and tables are in line with scientific norms and standards
In line with Frontiers author guidelines on editorial and ethical policies
Determined by grounding in existing literature through sufficient referencing and appropriate coverage of the relevant literature
Rejection criteria
A submission may be rejected at any stage before official publication of the article, including during initial validation, peer review, final validation and, if issues are identified late-stage, also post-acceptance, for the following reasons.
The manuscript does not have a valid research question or hypothesis
There are clear objective errors in the methodology of the study design, data collection, or analysis
The manuscript does not conform to our editorial policies as it is not original, is plagiarized, or is a duplication of previous work
The language and presentation of the manuscript is not of sufficient quality for a rigorous and efficient peer review to take place
The study violates our ethical policies by not complying with privacy protection guidelines, ethical review board approval guidelines, and internationally recognized standards for research involving humans or animals
The authors have not adhered to our authorship guidelines or have fabricated, falsified data or manipulated images and figures in a deceitful manner
The references are clearly biased (geographical, self-citation, school of thought, citation cartel) and do not reflect the current status of knowledge in the field
Based on biased or faulty analyses, the study’s conclusions are misleading and could even pose a public health threat
The study investigates a pseudoscientific research question
Peer review quality standards
Our editorial review operations team ensures a high quality, rigorous, and efficient peer-review process for all manuscripts submitted to Frontiers. The team establishes and upholds the peer-review guidelines for editors, reviewers, and authors, which incorporate the best practices and editorial policies.
The team is responsible for upholding the following quality standards:
Editors and reviewers are experts in the subject of the manuscript, with necessary expertise to evaluate the research by having established a sufficient research work or publication record on the same or related research area
Editors and reviewers have no relationship to the authors and/or research that would affect the objectivity of the peer-review process
In case the peer review is ongoing, and it is discovered that editors or reviewers do not have the relevant expertise or have a conflict-of-interest, they can be revoked and replaced during review by the peer review team and/or the editor
In case editors or reviewers inappropriately request the citation of their own published papers or the journal's (coercive citations), they can be revoked and replaced during review
Reviewers thoroughly complete the subject-specific questionnaire provided to assess the scientific rigor, quality, and validity of the manuscript they are reviewing. Review reports are verified to ensure they provide a constructive assessment of the manuscripts' validity and quality to the authors
Final editorial checks to verify that the peer-review process adhered to the quality standards, that the reviewers' and editor's concerns have been addressed, and that the manuscript is ready for publication
Only high-quality manuscripts that pass our acceptance criteria (listed above) are published.
In accepting a peer review assignment with Frontiers, editors and reviewers agree to:
have the necessary expertise to judge the manuscript's quality, rigor, and validity
submit thorough, high-quality review reports
provide feedback in a timely manner, remaining responsive to collaborate with the authors
behave in a professional, ethical way and be constructive during interactions with the editors, authors, and editorial team
abide by ethical publishing practices and refrain from requesting the addition of citations of their own articles, or the journal's articles (coercive citations), unless valid and justifiable academic reasons are conveyed.
As part of our quality standards, such practices will be monitored and may result in editors and reviewers being revoked from assignments and editorial board membership.
If an editor or reviewer fails to disclose ongoing collaborations that would affect their ability to perform an objective review, or be discovered to have otherwise manipulated the peer review process using fake identities, fake or deceptive review reports, or a ring of members to expedite manuscript review (peer review ring), all their involvement in peer review will be terminated, and any ongoing submissions rejected. The issue will be raised with the researchers' institutions.
The journal's chief editors and Frontiers' Chief Executive Editor retain the right after a decision has been made by the handling editor to request further manuscript revisions, additional expert evaluation, and to overrule either acceptance or rejection. This decisional power is part of Frontiers' editorial policies as well as the terms and conditions, which all authors agree to before manuscript submission. All submissions to Frontiers are subject to the same processes and editorial policies.
In parallel, for manuscripts to remain under consideration for publication, the authors must:
remain engaged with the peer review process and responsive for queries from the editors, reviewers, or Frontiers' editorial office
behave in a professional way, use constructive, respectful language when communicating with the editorial board members, reviewers, or the editorial office, and collaborate effectively during the peer review process.
Participants in the peer review will be removed from their assignments if they do not adhere to and meet these review standards. Manuscripts can also be rejected should the authors be unresponsive for an extended period of time (30 days) or use inappropriate, offensive language when communicating with the editorial board members or Frontiers' editorial office.
Full peer review guidelines
All article types undergo a full peer review, except for Editorials, Classifications, and Grand Challenges.
The full collaborative peer review process consists of two phases:
Independent review
During the independent review phase, the reviewers assess the manuscript independently from each other and from the authors, according to a standardized review template. These templates are adapted to each article type.Interactive review
During the interactive review phase, authors and reviewers can interact with each other through real-time comments in the discussion forum – with the aim of addressing all concerns about the manuscript. The handling editor oversees the review process, and, if required, the specialty chief editor can also enter the review forum.
Post-submission steps
Once a manuscript is submitted, our editorial office conducts a pre-screening for validation of research integrity and quality standards. If a manuscript meets Frontiers' quality criteria, an editor from the relevant specialty section is invited to handle the manuscript's peer-review process. After a preliminary content check, the editor decides whether to send the manuscript for review or to recommend it for immediate rejection to the specialty chief editor.
In the latter case, the specialty chief editor may confirm the handling editor's recommendation of immediate rejection due to the following reasons:
Objective errors in the methods, applications, or interpretations were identified in the manuscript that prevent further consideration
Ethical issues were identified in the manuscript that prevent further review or publication
The manuscript does not fulfill the standards established for the journal to be considered for publication (see full rejection criteria above).
The specialty chief editor may, nevertheless, override the handling editor's recommendation and decide that the manuscript deserves being reviewed before a final decision is made. In this case they will assign the manuscript to a new handling editor for another assessment.
The handling editor invites experts to review the manuscript; most article types require at least two reviewers to complete a review. These reviewers can either be invited from the board of review editors or appropriately recruited among experts in the field.
Handling editors: reviewer invitations
If a manuscript is sent for peer review, the handling editor is accountable for inviting and overseeing expert reviewers. Most article types require at least two reviewers to complete a review. These reviewers can either be invited from the board of review editors or appropriately recruited among experts in the field.
It is the prerogative of a handling editor to manage the reviewer recommendations of a manuscript. When the reviewers make their recommendation – to reject, revise, or accept the manuscript – the handling editor must validate this decision in line with our clearly defined acceptance and rejection criteria (see above).
If the handling editor disagrees with the final recommendation of a reviewer, whether it is to reject or accept the manuscript, it is the handling editor who is afforded the right to seek further expert feedback and invite an additional reviewer(s). In 2020, in nine out of 10 cases, the handling editors followed the recommendations from reviewers, to accept or reject, without seeking additional expert opinions.
Frontiers remains independent of this process and does not set or seek to influence acceptance or rejection rates. We are confident in the quality of our editors and peer-review process, whose proficiency has enabled Frontiers' open access publications to become one of the most highly cited in the world.
Independent review phase
The reviewers are asked to submit the standardized independent review report via the online collaborative review forum within seven days after accepting the assignment. This is done independently by each reviewer. The handling editor is automatically notified as soon as each of the reports is submitted, along with the recommendation of that reviewer. If the reviewer recommends acceptance, they are able to immediately endorse the manuscript and finalize their review.
Once all reviewers have submitted a report, the editor is responsible for activating the next phase, the interactive review, to release the review reports to the authors. If the editor would like to recommend rejection during the independent review phase, they can do so by activating the interactive review phase with major concerns, providing the authors with the reports and a unique opportunity for rebuttal during a defined timeframe.
Interactive review phase
Once the editor activates the interactive review phase, authors are immediately notified and granted access to the collaborative review forum, where they are able to view the reviewers' comments. Authors are asked to respond and/or submit a revised manuscript within seven, 10, or 14 days, depending on the level of revisions requested by the editor. If the authors are unresponsive to multiple communication attempts, the editorial office will send a final email to the authors with a seven-day deadline to respond. Following this, the editorial office reserves the right to withdraw the manuscript from the review process.
The editor can access and post comments in the collaborative review forum at any time. The editor also monitors the discussions occurring between authors and reviewers within the forum and ensures not only the timeliness, but also the constructiveness, of the participants' interactions.
If a dispute arises at this stage, the editor acts as a mediator, working with all parties involved to resolve the issues and even inviting new reviewers for further opinions if needed. If the disagreement persists, the specialty chief editor is then invited to enter the interactive review phase, assess the situation, and take a final decision as to whether the review should be ended by rejecting the manuscript or continued – potentially, but not necessarily, with a new handling editor and set of reviewers.
When a disagreement cannot be resolved to the satisfaction of a reviewer, they can choose to recommend rejection of the manuscript. The handling editor is then informed of the rejection recommendation and the reason. A reviewer can also withdraw from the review at any time. In both cases of rejection recommendation and withdrawal, the reviewer will no longer participate in the review forum, but may continue to follow the manuscript status under their My Frontiers page. The editor is informed of the reviewer recommendations and may choose to further recommend rejection to the chief editor, or invite other reviewers to receive additional expert opinions. If a reviewer submitted an independent review report prior to withdrawal or rejection recommendation, the report will be maintained in the review forum for participants to access throughout the review process. It is not removed or lost.
During this phase, a manuscript may be rejected at any point for the following reasons:
Objective errors in the methods, applications, or interpretations were identified in this manuscript that prevent further consideration
Ethical issues were identified in this manuscript that prevent further review or publication
The manuscript does not fulfill the standards established for the journal to be considered for publication
The manuscript could not be sufficiently revised by the authors to address the concerns raised by the reviewers or editor during the review process
Other reasons that meet the rejection criteria (listed above).
The review is complete only once all reviewer and editor comments have been satisfactorily addressed by the author.
Author triggered arbitration
If a dispute arises regarding the rejection of a manuscript, the authors may rebut the decision and trigger an arbitration.
Authors should provide enough information as part of their rebuttal so that an informed decision can be made on whether the grievance is valid. For example, if a rebuttal relates to lack of ethics approval, an author should provide a letter obtained from the relevant ethics committee as part of the rebuttal. Rebuttals should be factual and constructive. We will not consider rebuttals that contain inappropriate or derogatory language.
As a first step, the editorial office will arbitrate. They may discuss the case with editors and reviewers to try and resolve the dispute, depending on the peer review stage where rejection occurs and the reasons for rejection. At the discretion of the editorial office, independent experts may also be called for confidential arbitration evaluation. This process can include an assessment of rebuttal validity and/or the peer review process.
Depending on case complexity, authors should expect the arbitration process to take anywhere from a few weeks to several months. While a decision can take a significant amount of time, authors should anticipate receiving updates every 2–4 weeks.
Should an arbitration rule in favor of the authors, the editorial office will consider reinstating a manuscript to the stage where the rejection occurred and/or restarting the peer review process with a newly appointed editor and/or reviewer(s).
A manuscript will remain rejected if the arbitration rules that any of the above rejection criteria are met. While arbitration for a rejected manuscript is ongoing, authors should not submit a revised version of the manuscript.
Reviewer triggered arbitration
Reviewers are also entitled to trigger an arbitration if they judge that the authors are reluctant to make required changes as part of peer review. Reviewers may of course recommend rejection at any time or withdraw from the review process if they disagree with the arbitration ruling (in both cases their identity remains undisclosed). The withdrawal of a reviewer requires the recruitment of a replacement, which slows down the peer review process; therefore, authors are encouraged to cooperate as much as possible in addressing the concerns of the reviewers involved with their manuscript. Should an arbitration rule in favor of the authors, then the manuscript can be accepted even if there was a previous rejection recommendation.
Manuscript acceptance
If the reviewers endorse the publication of the manuscript in its current form, they must finalize their review reports, which automatically notifies the handling editor. For acceptance to be considered, the manuscript must:
be VALID as defined in the acceptance criteria above
have an editor and the minimum number of independent reviewers assigned for the article type
be endorsed by a majority of the assigned, non-withdrawn reviewers.
The editor can then either accept the final version of the manuscript or request further changes as necessary, typically within a few days. Acceptance of a manuscript can be decided by the handling editor and does not require the approval of the specialty chief editor.
Acceptance by the handling editor moves the article into the final validation phase, during which Frontiers' peer review team performs final technical and quality checks, including whether the review was performed adequately. Should the manuscript fail the final checks, it can either be put back into review to address the identified issue(s) or else the provisional acceptance decision can be overridden and the manuscript will be rejected at this stage without publication.
The article processing charge (APC) is payable within 30 days of acceptance and is required before final publication of the manuscript.
Manuscript rejection
If the minimum required number of reviewers to endorse the manuscript is not met (usually two, and must be a majority), then the handling editor must recommend to the specialty chief editor that the manuscript be rejected for publication. The final rejection decision is usually made by the specialty chief editor but can also be made by the research integrity team based on the rejection criteria above.
If a manuscript is rejected, no APC or other fee is charged.
Short peer review guidelines
Two article types, Editorials and Classifications, undergo a shortened peer review.
Short peer reviews differ from full peer reviews in two aspects: they are directly forwarded to the interactive review phase and they may be reviewed by the handling editor alone. It is up to the editor's consideration if further reviewers are invited to the review process.
Therefore, following submission, an editor of the relevant Frontiers specialty is immediately invited to take on the manuscript editorial assignment, which encompasses the role of the reviewer, too. Since no independent review report is required, the manuscript enters the interactive review phase immediately.
Interactive review, manuscript acceptance, and rejection follow the same rules as for full peer reviews.