Publication Ethics

Principles and Practice of Clinical Research (PPCR) follows the guidance of the Committee on Publication Ethics (COPE) and the ICMJE Recommendations. By submitting a manuscript, authors confirm that they accept these policies.

Contents: Authorship · Competing interests · Ethics approval and consent · Trial registration and reporting · Statistical reporting · Citation integrity · Image and data integrity · Use of artificial intelligence · Research integrity and misconduct · Preprints and prior publication · Corrections and retractions · Appeals and complaints

Authorship

Every author must meet all four ICMJE criteria:

substantial contribution to the conception or design of the work, or to the acquisition, analysis or interpretation of data;
drafting the work or revising it critically for important intellectual content;
final approval of the version to be published; and
agreement to be accountable for all aspects of the work, ensuring that questions about its accuracy or integrity are investigated and resolved.

Contributors who meet fewer than four criteria are listed in the Acknowledgments, with their permission. Funding, general supervision, data collection alone or holding a position does not justify authorship.

Contribution statement. Every research article includes a statement of each author's contribution using the CRediT taxonomy.
Large author groups. Every named author must meet all four criteria. A group may publish under a group name; members who meet the criteria are listed as authors and other members in the Acknowledgments.
Corresponding author. Each manuscript has one corresponding author, who handles all communication with the journal and ensures that all authors have approved the submission.
Equal contribution. Authors who contributed equally may be marked as such on the title page.
Changes to authorship. Adding, removing or reordering authors after submission requires a written explanation and the signed agreement of every author, including any author being removed. Authorship is not changed after acceptance, except through a published correction when an authorship dispute is resolved.
AI tools cannot be listed as authors.

Competing interests

Authors, reviewers and editors must declare any financial or non-financial interest that could influence, or appear to influence, their work. Declaring an interest is not an admission of wrongdoing and does not by itself prevent publication.

Financial interests include employment, consultancy, stocks, patents, royalties, grants, honoraria and paid travel, current or within the past three years.
Non-financial interests include unpaid advisory roles, membership of organizations, personal relationships with people involved in the work or its review, and strongly held political, religious or ideological positions related to the topic.

Each author completes the ICMJE disclosure form, and every published article includes a competing-interests statement (or "none declared") and a funding statement. Editors and reviewers withdraw from any manuscript where they have a competing interest; submissions by editors are handled as described in Editorial Process and Peer Review.

Ethics approval and consent

Ethics approval. Research involving people, their data or their tissue must have been approved by an ethics committee or institutional review board. The manuscript must name the committee and give the approval number and date. Research must follow the Declaration of Helsinki.
Consent to participate. Participants, or their legal representatives for minors and adults who lack capacity, must have given informed consent. An ethics committee may waive consent, for example for analyses of anonymized records; in that case the manuscript must state the waiver and the committee that granted it.
Public de-identified datasets. Secondary analyses of fully de-identified public datasets (for example, NHANES) may be exempt from ethics review. Authors must name the dataset, confirm compliance with its access terms, and state the basis for exemption.
Consent to publish. Any image, video, case detail or other information that could identify a person requires that person's written consent to publication (or a parent's or guardian's for minors). Masking the eyes is not sufficient. Identifiers such as names, initials and hospital numbers must not appear.
Research involving animals. PPCR considers animal research only when it is part of translational clinical work. Such studies must follow the ARRIVE guidelines and report approval under the applicable national regulations, including the committee and approval number.
Sex and gender. Authors are encouraged to report sex and gender of participants and to consider them in the analysis, following the SAGER guidelines.

Trial registration and reporting

Clinical trial registration. Clinical trials must be registered in ClinicalTrials.gov or a primary registry of the WHO ICTRP at or before the time of first participant enrollment. Retrospectively registered trials are not considered. The registration number appears at the end of the abstract. Secondary analyses cite the registration number of the original trial.
Reporting guidelines. Authors must follow and upload the checklist for the reporting guideline that matches their design, available from the EQUATOR Network: CONSORT (randomized trials), SPIRIT (protocols), STROBE (observational studies), PRISMA 2020 or PRISMA-ScR (systematic and scoping reviews), STARD (diagnostic accuracy), CARE (case reports). Registration of systematic reviews in PROSPERO, and of scoping reviews on OSF, is recommended.
Study protocols. Protocols are published only for studies with ethics or IRB approval and secured funding; the approval number and funder must be stated. Protocols for studies without approval and funding may be submitted as a Letter to the Editor making the case for the study.
Data availability. Every research article includes a data availability statement. See Open Access, Copyright and Data.

Statistical reporting

Describe the statistical methods in enough detail for a knowledgeable reader with access to the data to verify the results, including the software and version used.
Report effect sizes with 95% confidence intervals, not P values alone; give exact P values except when P < .001.
Distinguish pre-specified (primary) analyses from secondary and exploratory ones, and report any changes to the planned analysis.
Justify the sample size; for trials, report the sample-size calculation.
Report how missing data were handled and how many participants were included in each analysis.
Adjust for multiple comparisons where appropriate, or state that analyses were not adjusted and interpret them accordingly.

Editors may ask for an additional statistical review.

Citation integrity

Every reference must be read by the authors and must support the statement it is cited for.
References must be accurate and complete (authors, year, title, journal, volume, pages and DOI). Citations to sources that cannot be found or verified are not accepted.
Citation manipulation is not permitted. This includes excessive self-citation, citing to boost another journal or author, and editors or reviewers asking authors to cite their own work without scientific reason. Authors should report any such request to the editorial office.
Editors check references during review and before publication.

Image and data integrity

Figures must represent the original data accurately. Adjustments to brightness, contrast or color are allowed only when applied to the whole image and when they do not obscure, remove or misrepresent any information.
Elements must not be moved, added, removed or enhanced within an image, and images from different sources or experiments must not be combined without clear indication.
Authors must keep the raw data and original images underlying their results and provide them to the editors on request. Failure to do so may lead to rejection, correction or retraction.

Use of artificial intelligence

AI tools cannot be authors, because they cannot take responsibility for the work.
Authors who use AI tools for writing, analysis, coding or images must name the tool and describe how it was used in the Methods or Acknowledgments. Use for spelling and grammar correction alone need not be declared.
Authors are responsible for the accuracy of all content, including every reference. Citations generated or suggested by AI must be checked against the original source; fabricated or unverifiable references are grounds for rejection or retraction.
AI-generated images or figures are not accepted unless AI is the subject of the research and their use is fully described.
Reviewers and editors must not upload manuscripts, or their own reports, to generative AI tools.

Research integrity and misconduct

PPCR checks submissions for text similarity at submission and may repeat the check at later stages. Suspected misconduct, including fabrication, falsification, plagiarism, image manipulation, duplicate submission or publication, citation manipulation, undisclosed competing interests, authorship disputes and manuscripts produced by paper mills, is handled following the COPE flowcharts. The journal will contact the authors first and may inform their institutions or funders. Manuscripts may be rejected, and published articles corrected or retracted, as a result.

Preprints and prior publication

PPCR welcomes manuscripts previously posted as preprints, which are not considered prior publication. Authors must disclose the preprint at submission and should update it with a link to the published article. Conference abstracts are also not considered prior publication. Manuscripts must not be published elsewhere or under consideration by another journal.

Corrections, retractions and expressions of concern

PPCR follows the COPE retraction guidelines.

Correction. Published when an error affects the published record but not the article's conclusions. The correction notice is linked to the article, which is updated.
Retraction. Published when findings are unreliable, through honest error or misconduct, or in cases of plagiarism, duplicate publication or unethical research. The retraction notice states the reason and who is retracting. The article remains online, clearly marked "Retracted" on every page, and linked to the notice.
Expression of concern. Published when there is a serious concern about an article and an investigation is unresolved.
Withdrawal. Authors may withdraw a manuscript at any time before acceptance. Published articles are not removed, except where required by law or to protect a person's safety or privacy; otherwise they are corrected or retracted.
Raising a concern. Readers may raise concerns about a published article by writing to ppcr-journal@ppcr.org.

Appeals and complaints

Appeals. Authors may appeal a decision once, in writing to ppcr-journal@ppcr.org, within 30 days, explaining why they believe the decision was wrong and responding to the reviewers' points. The appeal is assessed by an editor who was not involved in the original decision, who may seek an additional review. The outcome of the appeal is final.
Complaints. Complaints about the handling of a manuscript, the conduct of an editor or reviewer, or publication ethics should be sent to ppcr-journal@ppcr.org. Complaints are acknowledged within 7 days and investigated by an editor not involved in the matter, who reports the outcome to the complainant.