Editorial Notes, Corrections, Expressions of Concern, and Retractions

PLOS publishes four types of post-publication notice:

• Editorial notes
• Corrections
• Expressions of Concern (EOCs)
• Retraction notices

These notices are issued DOIs and linked to the affected articles’ PLOS webpages. They are also identified by CrossMark as article updates.

As discussed below, we use editorial notes, corrections, EOCs, and retractions to address:

• Substantial editorial updates to an article or post-publication notice
• Errors that impact an article’s interpretation or indexing
• Concerns about compliance with journal standards and policies
• Concerns that have implications for the integrity, reliability, and/or validity of published PLOS articles

In addressing issues raised about PLOS publications, we uphold our journals’ policies, publication criteria, and editorial standards, and we follow ICMJE and COPE guidelines, where applicable. The PLOS Publication Ethics team works in collaboration with journal editors on post-publication cases that involve serious ethics or integrity concerns.

PLOS issues post-publication editorial decisions (editorial note, correction, EOC, or retraction) based on our assessment of the issues raised, materials and information received in follow-up discussions, and how the case details align with COPE guidance and PLOS’ policies and publication criteria. In accordance with COPE guidance, we attempt to discuss concerns with the article’s corresponding author before coming to a final editorial decision. For some cases, we also publish interim notices (editorial notes or EOCs) before we complete our assessment and/or follow-up discussions; interim notices are published at PLOS editors’ discretion.

After a post-publication editorial decision has been communicated to the authors, the decision is held during a brief commenting period in which authors can respond to the decision or notice text. After the commenting period’s end date, which is specified in the decision notification letter, the decision will proceed.

Editorial Notes

PLOS publishes editorial notes at staff editors’ discretion to inform readers of substantial updates or issues that may impact readers’ interpretation of a PLOS publication. We primarily use editorial notes for the following purposes:

• as interim notices, to inform readers of credible concerns for which editorial follow-up and/or investigations are pending, and for which PLOS does not feel an EOC or retraction is currently warranted based on the information we have received and evaluated to date; 
• as a post-publication case resolution, if the editors conclude that a published update to an article or notice is needed, but the update does not meet our criteria for a correction, EOC, or retraction. 

Editorial notes are authored by PLOS editors; we will attempt to inform authors before publishing an editorial note on their PLOS publication.

Unlike Corrections, PLOS does not consider author requests for editorial notes. 

Corrections

We publish corrections to address errors in PLOS articles if, per our editorial assessment, all of the following criteria have been met:

• The errors impact the main contents or understanding of the article.
• The article's overall results and conclusions are upheld.
• There are no concerns about the integrity or reliability of the reported work.

PLOS may also publish a correction to address an error or omission that affects key aspects of the publication’s metadata (e.g. an author's name, or the competing interests, funding, or data availability statement), or to provide an underlying dataset or additional information that the editors deem necessary for the article to meet the journal’s research reporting standards.

In most cases, corrections are not incorporated into the article’s contents directly. Instead, the updates are described in a separate notice that is linked to the PLOS article’s webpage.

In rare cases, PLOS may choose to republish a corrected version of an article, replacing the original online version. When we republish an article, we generally publish an accompanying correction, or notice of republication, that is linked to the article and documents the changes. However, we make exceptions to this practice in select circumstances. For example, we republish without accompanying notices (aka “silent corrections”) when updating author lists to reflect name changes for transgender or non-binary authors. (See the PLOS authorship change policy.)

PLOS does not publish corrections for typographical errors or other minor issues that do not substantively impact the article’s scientific integrity, understanding, or indexing. For these issues, authors are encouraged to update readers by posting comments on their article’s webpage. See the Comments guidelines for more information. Please email the journal office if you have questions about whether a correction or comment should be used to address an error in a PLOS article.

Expressions of Concern

Expressions of Concern (EOCs) are notices published at editors’ discretion to alert readers of serious concerns about published work or an article’s compliance with PLOS policies (e.g. Data Availability). In most cases, we will complete the case’s follow-up before publishing a notice, but in some instances we may publish an EOC as an interim notice while PLOS or another entity is investigating an issue. An EOC may also be used as a resolution to a post-publication case if we reach the conclusion of our follow-up process and issues remain unresolved.

EOCs are written by PLOS staff and/or the journal’s Editor(s)-in-Chief, Executive Editor, or Division Editor. When published, an EOC is posted at the top of the article’s PLOS webpage and linked to the article’s publication record, similar to a correction. An EOC does not change the publication status of the linked article. After an EOC is published, the same article may be corrected or retracted, or the EOC itself may be corrected or retracted, depending on the editors’ assessment of information, data, and/or materials received in subsequent discussions.

PLOS attempts to notify the authors of the affected article before publishing an EOC, but we do not require the authors’ approval or agreement. PLOS may seek to publish data or other materials received from the authors as supporting files with an EOC; in such cases, authors are consulted and can elect not to have their files/materials published, though this may affect the editorial decision to resolve the case with an EOC.

PLOS may notify affected third parties of an Expression of Concern. This could include, for example, the authors’ institution(s), an affected data repository, or another journal/publisher that has an article or submission involved in the case.

Retractions

As is discussed in COPE’s Retraction Guidelines, retraction is a mechanism for correcting the literature and notifying readers of major concerns about the integrity, validity, or reliability of an article.

• Authors may request retraction of their own work if issues come to light post-publication which call into question the scientific validity of the article, or which align with criteria listed in the COPE Retraction Guidelines. Any author-originated retraction request is subject to review and approval by the PLOS Publication Ethics team and/or Editor(s)-in-Chief, and will be denied if the issues raised do not align with COPE guidance and/or PLOS standards for retraction.
• When concerns are noted internally or are raised by third parties, PLOS follows up in accordance with COPE guidance and will retract an article if the editors determine that issues which are not resolved in post-publication discussions warrant retraction per COPE guidance. PLOS may also retract an article if we conclude that it does not adhere to key aspects of the journal’s requirements or editorial policies; or if there are image or data concerns for which the original raw data are not provided, not available, or not sufficient (per our editorial assessment) to address the issues.

We may retract an article whether the issues have arisen due to honest error(s) or misconduct. In accordance with COPE guidance, PLOS does not adjudicate on intent or individual-level responsibility for issues raised, and we do not issue partial retractions.

When retracting an article, PLOS publishes a notice of retraction that explains the reason(s) for the retraction. The notice is posted at the top of the affected article’s PLOS webpage and is linked to the article’s publication record. PLOS editors have final say on the retraction notice contents, but depending on case details we may collaborate with the authors in preparing the notice and/or give the article’s authors the option to be listed as authors of the retraction notice.

We attempt to notify all authors of a retraction decision and the notice text before completing a retraction. PLOS may also notify other affected third parties of a retraction; this could include, for example, the authors’ institution(s), an affected data repository, or another journal/publisher that has an article or submission involved in the case.

After an article is retracted, it is no longer considered to be part of the standing published record. Except in rare circumstances (see “Removal of PLOS Content”), retracted PLOS articles remain online and available as per COPE guidance, with the retracted status clearly indicated. At the time of retraction we update the downloadable PDF that is available at the article’s PLOS webpage, so that for subsequent downloads the retracted status is clearly noted on the PDF.

If a retracted article contains select elements (e.g. figures or tables) that are similar to or that duplicate published content, and if the original publication of that content is not available under a Creative Commons (CC) open access license, we may update the PLOS article’s copyright statement at the time of retraction to exclude those elements from the CC-BY license.

PLOS does not refund Article Processing Charges (APCs) following retraction.

Publication of Previously Retracted Work

After a retraction, if authors are able to resolve all issues underlying the retraction decision and wish to pursue republication in a PLOS journal, they should contact the relevant journal office and inquire about PLOS’ requirements for submissions of previously retracted work. We will not consider a revised version of an article for publication if there are unresolved concerns involving potential misconduct.

If a revised version of a retracted article is peer reviewed and accepted for publication it will receive a new DOI and the original (retracted) article will remain available online, clearly marked as retracted unless the case warrants consideration for removal (see ‘Removal of PLOS Content’). The original article, retraction notice, and updated article will be linked as related content via their PLOS journal webpages.

Removal of PLOS Content

PLOS reserves the right to remove contents from our journal webpages in exceptional circumstances such as:

• a court or government order has requested the removal;
• the content presents a risk to personal privacy or to a third party’s legal rights, and the risk cannot be suitably mitigated by an editorial notice or other article updates;
• the research was not lawfully conducted or published, and/or its continued availability presents potential legal or personal privacy risk(s);
• cases of dual publication in which the PLOS content duplicates previously published material that is not available under an open access (Creative Commons) license; or
• per PLOS editors’ assessment, the contents - even if marked as retracted - may present a substantial risk, for example to public health or to a specific community or ecosystem.

When PLOS removes an article, the title, author list, and article metadata remain available on the article’s PLOS webpage, along with an editorial notice.

Appeals of Post-Publication Decisions

PLOS will only consider appeals of Retraction or Expression of Concern decisions if both of the following criteria are met:

• new information and/or data are provided that directly address the issue(s) underlying the decision (e.g. original raw data for cases involving image or data concerns, documentation of an investigation outcome from an institutional official), and
• the appeal is received before the specified commenting deadline.

Appeals are considered by the PLOS Publication Ethics team, and may be discussed with the journal’s Editor(s)-in-Chief, Executive Editor, or Division Editor, and/or with external scientific advisors or members of the journal’s Editorial Board.

Decisions on retraction and Expression of Concern appeals are final. We will not consider further rounds of appeal.