EDITORIAL POLICY UPDATE: Our Response to the Coronavirus Pandemic
Sharing relevant research data and findings: The Science Journals are signatories to the 2016 Statement on Data Sharing in Public Health Emergencies. The statement has been updated to address the 2019-nCoV outbreak. The update reaffirms the principles of rapid access to research data and papers relevant to the outbreak. Details can be found here: https://wellcome.ac.uk/press-release/sharing-research-data-and-findings-relevant-novel-coronavirus-ncov-outbreak.
Adapting our processes: In line with scientific recommendations, all editorial and operational staff of AAAS and the Science Journals are working from home during the COVID-19 pandemic. We could be working remotely for an extended period and we ask for your patience if this causes processing delays. We know that the outbreak is similarly impacting many of you – our authors, reviewers and readers. We all need to be flexible and patient during this difficult time. We thank you for your understanding. If you need help during the submission process, please email firstname.lastname@example.org. Please read our Editor’s Blog (https://blogs.sciencemag.org/editors-blog/) to learn more about our response to this continually evolving crisis.
This section outlines our Editorial Policies for all Science Journals. For journal specific Information for Authors follow the appropriate link:
Authors in Science Journals must fulfill the criteria described below that are informed by the ICMJE (International Committee of Medical Journal Editors) definition of authorship. Specifically,
- Each author is expected to have made substantial contributions to the conception or design of the work;
- OR the acquisition, analysis, or interpretation of data;
- OR creation of new software used in the work;
- OR have drafted the work or substantially revised it;
- AND has approved the submitted version (and any substantially modified version that involves the author’s contribution to the study;
- AND agrees to be personally accountable for the author’s own contributions and for ensuring that questions related to the accuracy or integrity of any part of the work, even ones in which the author was not personally involved, are appropriately investigated, resolved, and documented in the literature.
Exclusion from authorship of individuals who have made author-level contributions is not permitted for papers published in Science Journals. Nor is guest or honorary authorship. Other individuals who have participated in generation of the research paper but who do not meet the criteria for authorship should be listed in the acknowledgments section with a brief indication of the nature of their contribution.
In addition, corresponding authors must:
- Ensure that all listed authors have received and approved the manuscript prior to submission.
- Receive all substantive correspondence with editors as well as full reviews.
- Verify that all data, materials (including reagents), and code, even those developed/provided by other authors, comply with the transparency and reproducibility standards of both the field and the journal.
- Ensure that original data/materials/code upon which the submission is based are preserved and retrievable for reanalysis.
- Confirm that the presentation in the paper of the data/materials/code accurately reflects the original sources.
- Foresee and minimize obstacles to the sharing of data/materials/code.
- Ensure the entire author group is fully aware of and in compliance with best practices.
- Be responsible for signing off on galleys and ensuring all authors complete the COI declaration and license forms.
Any changes in authorship must be approved in writing by all of the original authors. A Science Journal will send an email to all authors to confirm receipt of each paper. Submission of a paper that has not been approved by all authors may result in immediate rejection without appeal.
For manuscripts that are accepted, all authors are required to affirm and explain their contribution to the manuscript, agree to the conditions of publication including the availability of data, code, and materials, and declare any conflicts of interest. The senior author from each group is required to have examined the raw data their group has produced. We encourage all authors to state their contribution to the study in the acknowledgments section following the CRediT model; this information will be published in the paper.
Conflict of Interest
Authors. Every author of content submitted to a Science family journal is required to disclose affiliations, funding sources, and competing interests that might be perceived as sources of bias related to the reported research and/or presented content. Specific details about the required disclosures are listed below along with information about placement of these disclosures within the article. This policy applies to research, reviews, and opinion-type articles.
Science/AAAS journals require disclosure of:
- Institutional affiliations
The title page of every submission must include for all authors the academic, corporate, government, industry, and/or other relevant institutional affiliations where the work was performed.
- Funding and contributions
All authors must disclose complete and correct information about any and all financial contributions to the work being reported This information should be listed in the Funding statement in the Acknowledgements section of the manuscript to ensure transparency during the review process and will be included in the final published work. Non-monetary (in-kind) contribution of goods or services may, if appropriate, be cited in published acknowledgments in the paper.
- Competing interests
All authors must disclose complete and correct details of competing interests that have occurred within 5 years of inception of the research or clinical study under consideration. Interests outside the 5-year time frame must also be declared if they could reasonably be perceived as competing. When in doubt, authors should disclose the relationship. This information should be summarized in a Competing interests statement in the Acknowledgments section of the final published work. Authors can provide a URL to a list of an author’s affiliations/interests/relationships in addition to the Competing interests statement.
A competing interest exists when one’s professional judgment about the execution of the research and/or the presentation of the content is, or could reasonably be perceived to be, influenced by other interests. Review the examples below in the context of the 5-year time frame mentioned above when preparing your Competing interests statement.
Financial competing interests include but are not limited to:
- Awarded, planned, or pending patents, including individual applications or those belonging to the institution to which the authors are affiliated and from which the authors may benefit
- Ownership of stocks, shares, or stock options even if not publicly traded
- Paid employment or consultancy
- Received payment for serving as a member of an Advisory Committee and/or as an officer/member of the Board for any entity engaged in activity related to the subject matter of this contribution
Non-financial competing interests that could impact the research reported here include but are not limited to:
- Acting as an expert witness
- Member of a government or other advisory board
- Relationship (paid or unpaid) with organizations and funding bodies, including nongovernmental organizations, research institutions, or charities
- Membership in lobbying or advocacy organizations • Writing or consulting for a company whose activities might impact the objectivity of this paper
- Personal relationships (e.g. friend, spouse/partner, family member, mentor, adversary) that could affect objectivity.
- Personal beliefs (political, religious, ideological, or other) related to a paper’s topic that might interfere with an unbiased publication process (at the stage of authorship, peer review, editorial decision-making, or publication)
Reviewers. Reviewers form the cornerstone of the peer review process, and their evaluations ensure the quality of published research. Therefore, the editors seek reviewers for Science Journals who do not have conflicts of interest with the authors or reported research in the manuscripts they read. In addition to this precaution, reviewers are required to disclose any conflicts with the evaluation of the paper, and this information is taken into account by the editors when decisions are made.
Professional Editors. Editors for Science, Science Signaling, Science Translational Medicine, and Science Immunology are required to fill out a conflict of interest form, which is then evaluated by Science Journals/AAAS management. Professional editors for the Science Journals may not have any financial or management interest in any biotechnology, pharmaceutical or biomedical or engineering device, institution or company.
Academic Editors. Editors for Science Advances and Science Robotics are required to disclose any conflicts with the evaluation of the paper and may be required to recuse themselves based on conflicts of interest.
Advisors & Reviewing Editors. Members of Science Journals’ Advisory Boards may be consulted by the staff editors at the initial evaluation of newly submitted manuscripts. They are required to declare any conflicts pertaining to particular submissions.
Prior Publication and Presentations at Meetings
The Science Journals will not consider any original research paper or component of a research paper that has been published or is under consideration for publication elsewhere. Distribution on the Internet may be considered prior publication and may compromise the originality of the paper as a submission to a Science Journal. We do not regard dissertations/theses as prior publications. We do support posting of research papers on not-for-profit preprint servers such as arXiv.org and bioRxiv.org. While a manuscript is under consideration at a Science Journal no versions revised in response to editorial input and peer review should be posted on a preprint server. Manuscripts posted at a preprint server should not be discussed with the media prior to publication. Please contact the editors with questions regarding allowable postings to other servers.
We generally encourage presentation of original results prior to publication at scientific meetings. Nevertheless, press coverage and presentation at scientific conferences can sometimes affect consideration of papers at the Science Journals. For example, reporting the main findings of a paper in the mass media can compromise the novelty of the work and thus its appropriateness for a Science Journal. Therefore, authors should feel free to present their data at scientific meetings but should not overtly seek media attention or give copies of the figures or data from their manuscript to any reporter. If a reporter attends an author's session at a meeting and writes a story based only on the presentation, such coverage will not affect a Science Journal’s consideration of the author's paper.
Unpublished Data and Personal Communications
Citations to unpublished data and personal communications cannot be used to support significant claims in the paper. Papers will be held for publication until all “in press” citations are either published or posted in full on a preprint server.
Copies of any papers by any subset of the authors that are related to the submitted manuscript and are under consideration or in press at other journals must be included with the submission of the original and/or revised version of the paper. While your paper is under consideration at a Science Journal, please contact your editor if a related paper is submitted elsewhere. Access to this material will let the editors put the results in the submission in the proper context and make the best decision regarding the submitted manuscript. Failure to disclose related papers may lead to rejection.
Authors and reviewers are expected to notify editors if a manuscript could be considered to report Dual Use Research of Concern (DURC). The National Science Advisory Board for Biosecurity has defined DURC as “life sciences research that, based on current understanding, can be reasonably anticipated to provide knowledge, information, products, or technologies that could be directly misapplied to pose a significant threat with broad potential consequences to public health and safety, agricultural crops and other plants, animals, the environment, materiel, or national security”. Papers identified as possible DURC will be brought to the attention of the Editor-in-Chief for further evaluation. If necessary, outside reviewers with expertise in the area will be consulted.
The Science Journals support the Transparency and Openness Promotion (TOP) guidelines to raise the quality of research published in Science and to increase transparency regarding the evidence on which conclusions are based.
1. Citation standards
All data, program code, and other methods must be appropriately cited using DOIs, journal citations, or other persistent identifiers. Truly exceptional circumstances requiring special treatment, such as proprietary information requiring nondisclosure agreements, should be discussed with the editor no later than at the manuscript revision stage and spelled out explicitly in the acknowledgments.
2. Data standards
All data used in the analysis must be available to any researcher for purposes of reproducing or extending the analysis. Data must be available in the paper, deposited in a community special-purpose repository, accessible via a general-purpose repository such as Dryad, or otherwise openly available (see Data Deposition). Truly exceptional circumstances requiring special treatment, such as protecting personal privacy, should be discussed with the editor no later than at the manuscript revision stage and spelled out explicitly in the acknowledgments. Problems in obtaining access to published data are taken seriously by the Science Journals and can be reported at email@example.com.
3. Analytic methods (code) transparency
We require that all computer code used for modeling and/or data analysis that is not commercially available be deposited in a publicly accessible repository upon publication. In rare exceptional cases where security concerns or competing commercial interests pose a conflict, code-sharing arrangements that still facilitate reproduction of the work should be discussed with your Editor no later than the revision stage.
4. Research materials transparency
The Science Journals require the Materials and Methods section to provide sufficient detail to allow replication of the study. Study design should be described in detail and reagent description should facilitate replication (for example source and purity should be specified, there should be evidence that antibodies have been validated, and cell lines should be authenticated). Statistics must also be comprehensively described as outlined below.
Materials/samples used in the analysis must be made available to any researcher for purposes of directly replicating the procedure. Authors are also expected to honor reasonable (consistent with community standards) requests for research materials/samples to the extent feasible, so that other research groups can extend and advance the results. Any restrictions on the availability of samples or special permit requirements that restrict use or sharing of samples should be discussed with the editor no later than at the manuscript revision stage and spelled out explicitly in the acknowledgments.
5. Design and analysis transparency
The Science Journals encourage authors to follow relevant standards for their field for reporting key aspects of the research design and analysis. Authors should report which standards were followed and note any deviations from the guidelines. Where applicable, note which guidelines were followed.
A chart providing links to major biomedical research reporting guidelines is available at the U.S. National Library of Medicine. Other guidelines may be found at the relevant society website: for example the American Chemical Society gives standards for the characterization of organic and inorganic molecular compounds.
See Guidelines for specific types of studies below.
6. Preregistration of studies
If the study that is submitted to a Science Journal for publication was preregistered, such as at the Center for Open Science’s Open Science Framework or ClinicalTrials.gov, authors should provide a link to the registration of the study upon submission of the paper to a Science Journal.
7. Preregistration of analysis plans
If the analysis plan was preregistered in an independent institutional registry, authors should provide a link to the registration of the analysis plan upon submission of the paper to a Science Journal.
The Science Journals encourage the submission of replication studies that provide new insights into previously published results. We hold replication studies to the same standards as other content submitted to the journals.
Authors should describe statistical methods with enough detail to enable a knowledgeable reader with access to the original data to verify the results.
- Data pre-processing steps such as transformations, re-coding, re-scaling, normalization, truncation, and handling of below detectable level readings and outliers should be fully described; any removal or modification of data values must be fully acknowledged and justified.
- Descriptive statistics should be presented for variables that are integral to subsequent analyses and interpretation of the study findings.
- The number of sampled units, N, upon which each reported statistic is based must be stated.
- For continuous variables, distributions should be described using graphical displays such as scatterplots, boxplots, or histograms or by reporting measures of central tendency (e.g., mean or median) and dispersion (e.g., SD, interquartile range).
- For continuous variables that are approximately normally distributed, mean and SD are suitable measures for center and dispersion, respectively.
- For continuous variables with asymmetrical distributions, median and range (or interquartile range) are preferred to mean and SD.
- All measures of central tendency or dispersion that are used should be identified.
- For very small samples sizes (e.g., N < 20), presentation of all data values in tabular format is desirable unless presentation would violate restrictions for privacy or confidentiality for human subjects.
- Units should be supplied for all measurements.
- Methods used for conducting statistical tests (e.g., t-test, Wilcoxon signed rank test, Wald test of regression coefficient) and for constructing confidence intervals (e.g., normal-based 95% CI: mean ± 2SD, likelihood ratio-based interval) should be clearly stated. Mention methods used in the Materials and Methods and then provide the individual test name in the figure legend for each experiment.
- The testing level (alpha) and whether one-sided or two-sided testing was used should be reported for each statistical test; typically two-sided testing is appropriate, but if one-sided testing is used its use should be justified.
- Adjustments made to alpha levels (e.g., Bonferroni correction) or other procedure used to account for multiple testing (e.g., false discovery rate control) should be reported.
- When Bayesian analyses are conducted, any assumptions made for prior distributions must be fully described.
- Sufficient information should be supplied to allow readers to judge whether any assumptions necessary for the validity of statistical approaches (e.g., data are normally distributed, survival data are consistent with proportional hazards in a Cox regression model) have been verified.
- An accounting of missing data values should be provided; if imputed data values are used in statistical analyses, the methods used for imputation should be fully described.
Authors should present results in complete and transparent fashion so that stated conclusions are backed by appropriate statistical evaluation and limitations of the study are frankly discussed.
- Point estimates of population parameters (e.g., mean, correlation coefficient, slope) or comparative measures (e.g., mean difference, odds ratio, hazard ratio) should be accompanied by a measure of uncertainty such as a standard error or a confidence interval.
- Results of each statistical test should be reported in full with the value of the test statistic and p-value, and not simply reported as significant or non-significant; more than two significant digits on p-values are usually not needed except in situations of extreme multiple testing such as in genetic association studies where stringent corrections for multiple testing might be used.
- Any results that are reported to constitute a blinded, independent validation of a statistical model (or mathematical classifier or predictor) must be accompanied by a detailed explanation that includes: 1) specification of the exact “locked down” form of the model, including all data processing steps, algorithm for calculating the model output, and any cutpoints that might be applied to the model output for final classification, 2) date on which the model or predictor was fully locked down in exactly the form described, 3) name of the individual(s) who maintained the blinded data and oversaw the evaluation (e.g., honest broker), 4) statement of assurance that no modifications, additions, or exclusion were made to the validation data set from the point at which the model was locked down and that neither the validation data nor any subset of it had ever been used to assess or refine the model being tested
For all laboratory animal experimentation described in the manuscript, the Science Journals require that authors state in the Methods section their adherence to the NIH Guide for the Care and Use of Laboratory Animals, or the equivalent. Species, strain, sex, and age of laboratory animals should be provided in the main text or Supplementary Materials.
Genetically modified animals. To avoid confounding effects of inbred strain background, littermate controls should generally be used, although exceptions may be allowed. Justification for other control animals should be included. Authors should fully describe the source of their animals and number of times backcrosses were performed
Human subjects research
Informed consent must be obtained for studies on humans after the nature and possible consequences of the studies are explained. A statement that informed consent was obtained must also appear in the manuscript. All research on humans must have approval from the institutional IRB (Institutional Review Board) or an equivalent body. The editors reserve the right to request IRB documents associated with a particular paper. Gender and age of all subjects should be provided in the main text or Supplementary Materials.
A CONSORT Statement includes recommendations, a checklist of items that should be included in a comprehensive report, and a participant flow diagram. The recommended checklist should be completed and provided at the time of manuscript submission. The recommended trial flow diagram may be presented as a figure (usually Fig. 1). Reports of randomized controlled trials that do not conform to the CONSORT guidelines may be returned to authors for revision prior to formal review.
Registration of clinical trials. Clinical trials should generally be registered in accordance with the criteria outlined by the International Committee of Medical Journal Editors, including the June 2007 update. Authors should provide the trial registration number in the Acknowledgements section and provide a link to the trial registration, to be cited as a reference.
Putative biomarkers must be evaluated with an independent validation set. Reports of unvalidated biomarkers will only be considered in the context of a clear experimental, mechanistic connection to disease or other unique contribution to understanding of disease or clinical practice. A statement should be included in all biomarker papers describing how overfitting (training models on large numbers of variables measured on small numbers of subjects) and other forms of bias were avoided. We strongly recommend all papers reporting potential new biomarkers be evaluated by an independent statistician before submission.
Computational models should be validated either experimentally or through a dataset independent of the training set. All assumptions should be clearly stated with sources provided in the references and notes section. [See Research Standards for code availability requirements]
Small molecule studies
All studies that make use of chemical compounds (including pharmaceutical research) must disclose the full structures of those compounds, including stereochemistry if known. If the compounds are not readily available from commercial sources, the methods used for their preparation, purification, and characterization must be disclosed in full detail. 1H and 13C nuclear magnetic resonance spectra should be included in supplementary materials for all synthesized organic compounds.
The Science Journals support the efforts of databases that aggregate published data for the use of the scientific community. Therefore, before publication, large data sets (including microarray data, protein or DNA sequences, atomic coordinates or electron microscopy maps for molecular and macromolecular structures, and climate data) must be deposited in an approved database and an accession number or a specific access address must be included in the published paper. We encourage compliance with MIBBI guidelines (Minimum Information for Biological and Biomedical Investigations).
Details include, but are not limited to:
- Molecular and macromolecular structure data. Atomic coordinates and structure factor files from x-ray structural studies or an ensemble of atomic coordinates from NMR structural studies must be deposited and released at the time of publication. Three-dimensional maps derived by electron microscopy and coordinate data derived from these maps must also be deposited. Approved databases are the Worldwide Protein Data Bank [through the Research Collaboratory for Structural Bioinformatics, Macromolecular Structure Database (MSD EMBL-EBI), or Protein Data Bank Japan], BioMag Res Bank, and Electron Microscopy Data Bank (MSD-EBI), and for synthetic compounds, the Cambridge Crystallographic Data Centre (organic/organometallic), or the Inorganic Crystal Structure Database. We require authors of papers reporting structural data to initiate deposition of the model and data at wwPDB and provide a Preliminary Full or Full validation report from the deposition server (for macromolecules) or CIF and checkCIF files (for synthetic compounds) with their submission. If these are not provided, they will be requested for review. We may also request electron microscopy density maps during the review process.
- DNA and protein sequences. Approved databases are GenBank or other members of the International Nucleotide Sequence Database Collaboration (EMBL or DDBJ) and SWISS-PROT.
- Microarray data. Data should be presented in MIAME-compliant standard format. Approved databases are Gene Expression Omnibus and ArrayExpress.
- Climate and Earth and Space Sciences data. Guidelines on data deposition are provided by the Coalition on Publishing Data in the Earth and Space Sciences (COPDESS), together with a searchable online Repository Finder.
- Ecological data. We recommend deposition of data in Dryad.
- General data sets without an appropriate specialized repository that are too large to be included as supplementary materials at a Science Journal should be deposited at a general repository such as Dryad. Complex, dynamic databases, can be made accessible through an institutional website, but an archived static version should be deposited at a general repository and the DOI included in the Science Journals paper. In rare cases where there is no appropriate repository, authors will be required to sign an agreement to make a copy of the database, as it exists at the time of publication, publicly available on their own websites for a period of at least five years after the paper's publication date. The authors would also be required to submit to the Science Journal a zipped archive of the same website with complete instructions for unzipping and installing the database, and to sign a declaration certifying that the copy is the same as that on the publicly available website. Further questions can be directed to your editor.
After publication, all data and materials necessary to understand, assess, and extend the conclusions of the manuscript must be available to any reader of a Science Journal. After publication, all reasonable requests for data, code, or materials must be fulfilled. Any restrictions on the availability of data, code, or materials, including fees and restrictions on original data obtained from other sources must be disclosed to the editors as must any Material Transfer Agreements (MTAs) pertaining to data or materials used or produced in this research, that place constraints on providing these data, code, or materials. Patents (whether applications or awards to the authors or home institutions) related to the work should also be declared.
Fossils or other rare specimens must be deposited in a public museum or repository and available for research.
Unreasonable restrictions on data, code, or material availability may preclude publication. Problems in obtaining access to published data are taken seriously by the Science Journals and can be reported at firstname.lastname@example.org.
Science, Science Signaling, Science Translational Medicine, Science Immunology, and Science Robotics require that, before manuscript acceptance, authors sign a license agreement granting AAAS exclusive rights to use and authorize use of their contribution. The authors retain copyright as well as rights to make certain uses of the work, which are described in detail in the information for authors that accompanies the form. Authors should read this information sheet before signing the agreement. (A separate form is used for authors of papers for which all coauthors are employees of the Australian, Canadian, and/or U.K. Government.)
In general, authors will complete the license form as a "click-through" during the process of uploading the revised manuscript after peer review.
License to Publish: Form [PDF]
Science Advances requires that, before manuscript acceptance, authors sign a license agreement granting AAAS exclusive rights to use and authorize use of their contribution. As an open access journal, Science Advances then asks authors to choose one of two Creative Commons licenses, each of which allows readers to reuse the published content in specific ways. The CC BY-NC license allows readers to distribute, adapt, or reuse articles for non-commercial purposes, while commercial reuse requires permission. The CC BY license, available for a surcharge, allows readers to distribute, adapt, or reuse articles, including for commercial purposes. Further licensing and APC pricing information is found here.
Immediately after publication, authors may post the accepted version of their paper on their personal or institutional archival website. In addition, one author is provided a "referrer" link, which can be posted on a personal or institutional web page and through which users can freely access the final, published paper on the Science Journal’s website.
For research papers created under grants for which the authors are required by their funding agencies to make their research results publicly available (for example, from NIH, Howard Hughes Medical Institute, or Wellcome Trust), we allow posting of the accepted version of research content (research articles, research reports, research resources, review articles, or technical comments) to the funding body's archive or designated repository (such as PubMed Central) no sooner than six months after publication, provided that a link to the final version of the paper published in the Science Journal is included. The accepted version is the version of the paper accepted for publication after changes resulting from peer review, but before editing by the Science Journal copyediting staff, image quality control, and production of the final PDF.
Authors from institutions that might limit the authors' ability to grant to AAAS any of the rights described in AAAS's license must obtain an approved waiver from their institution to publish with the Science Journal.
Original research papers are freely accessible with registration on the Science Journal’s website 12 months after publication.
For authors with funding from The Bill & Melinda Gates Foundation (BMGF), note that AAAS's pilot open access partnership with the Gates Foundation concluded on June 30, 2018. Manuscripts submitted to Science, Science Immunology, Science Signaling, Science Translational Medicine, or Science Robotics on or before June 30, 2018 that are accepted for publication will be included in the pilot. After July 1, 2018, BMGF grantees are responsible for complying with the foundation’s policies.
Access Policies for Science Advances
Science Advances is an online-only gold open access journal from AAAS. All content is freely available from the date of publication.
The cost of color illustrations is $650 for the first color figure and $450 for each additional color figure. In addition, there is a comparable charge for use of color in reprints. We ask that you submit your payment with your reprint order, which you will receive with your galley proofs. We also now provide a free electronic reprint service; information will be sent by email after your paper is published.
Submitted and accepted papers must remain privileged documents and must not be released to the press or the public before publication. The Science Journals do allow posting of the submitted version of research papers on not-for-profit preprint servers, but these should not be discussed with the media. We provide embargoed press packages to reporters ahead of publication to facilitate accurate reporting on our published papers. Questions should be referred to the AAAS Office of Public Programs (202-326-6440).
Science is a member of COPE (Committee on Publication Ethics) and all Science Journals are committed to correcting errors in published papers. In cases where an institutional investigation of large-scale error or misconduct is under way, a Science Journal may publish an Editorial Expression of Concern relating to the paper in question. In cases of irreproducibility of research findings reported in a Science Journal paper, a retraction may be considered if the core conclusions are thereby invalidated. Papers will also be retracted in case of research misconduct, in accord with COPE guidelines. Corrections to errors that do not affect the core conclusions of a paper are posted online and linked to the published paper.