prespecified subgroup analyses should be described. Provide only directly pertinent references, and do not include data or conclusions from the work being reported.

#### IV. A. 6. Methods

The Methods section should include only information that was available at the time the plan or protocol for the study was being written; all information obtained during the study belongs in the Results section.

#### IV. A. 6. a. Selection and Description of Participants

Describe your selection of the observational or experimental participants (patients or laboratory animals, including controls) clearly, including eligibility and exclusion criteria and a description of the source population. Because the relevance of such variables as age and sex to the object of research is not always clear, authors should explain their use when they are included in a study report—for example, authors should explain why only participants of certain ages were included or why women were excluded. The guiding principle should be clarity about how and why a study was done in a particular way. When authors use such variables as race or ethnicity, they should define how they measured these variables and justify their relevance.

#### IV. A. 6. b. Technical Information

Identify the methods, apparatus (give the manufacturer's name and address in parentheses), and procedures in sufficient detail to allow others to reproduce the results. Give references to established methods, including statistical methods (see below); provide references and brief descriptions for methods that have been published but are not well-known; describe new or substantially modified methods, give the reasons for using them, and evaluate their limitations. Identify precisely all drugs and chemicals used, including generic name(s), dose(s), and route(s) of administration.

Authors submitting review manuscripts should include a section describing the methods used for locating, selecting, extracting, and synthesizing data. These methods should also be summarized in the abstract.

#### IV. A. 6. c. Statistics

Describe statistical methods with enough detail to enable a knowledgeable reader with access to the original data to verify the reported results. When possible, quantify findings and present them with appropriate indicators of measurement error or uncertainty (such as confidence intervals). Avoid relying solely on statistical hypothesis testing, such as *P* values, which fail to convey important information about effect size. References for the design of the study and statistical methods should be to standard works when possible (with pages stated). Define statistical terms, abbreviations, and most symbols. Specify the computer software used.

#### IV. A. 7. Results

Present your results in logical sequence in the text, tables, and illustrations, giving the main or most important findings first. Do not repeat all the data in the tables or illustrations in the text: emphasize or summarize only the most important observations. Extra or supplementary materials and technical detail can be placed in an appendix where they will be accessible but will not interrupt the flow of the text, or they can be published solely in the electronic version of the journal.

When data are summarized in the Results section, give numeric results not only as derivatives (for example, percentages) but also as the absolute numbers from which the derivatives were calculated, and specify the statistical methods used to analyze them. Restrict tables and figures to those needed to explain the argument of the paper and to assess supporting data. Use graphs as an alternative to tables with many entries; do not duplicate data in graphs and tables. Avoid nontechnical uses of technical terms in statistics, such as "random" (which implies a randomizing device), "normal," "significant," "correlations," and "sample."

Where scientifically appropriate, analyses of the data by such variables as age and sex should be included.

#### IV. A. 8. Discussion

Emphasize the new and important aspects of the study and the conclusions that follow from them in the context of the totality of the best available evidence. Do not repeat in detail data or other information given in the Introduction or the Results section. For experimental studies, it is useful to begin the discussion by briefly summarizing the main findings, then explore possible mechanisms or explanations for these findings, compare and contrast the results with other relevant studies, state the limitations of the study, and explore the implications of the findings for future research and for clinical practice.

Link the conclusions with the goals of the study but avoid unqualified statements and conclusions not adequately supported by the data. In particular, avoid making statements on economic benefits and costs unless the manuscript includes the appropriate economic data and analyses. Avoid claiming priority or alluding to work that has not been completed. State new hypotheses when warranted, but label them clearly as such.

#### IV. A. 9. References

#### IV. A. 9. a. General Considerations Related to References

Although references to review articles can be an efficient way to guide readers to a body of literature, review articles do not always reflect original work accurately. Readers should therefore be provided with direct references to original research sources whenever possible. On the other hand, extensive lists of references to original work on
a topic can use excessive space on the printed page. Small numbers of references to key original papers often serve as well as more exhaustive lists, particularly since references can now be added to the electronic version of published papers, and since electronic literature searching allows readers to retrieve published literature efficiently.

Avoid using abstracts as references. References to papers accepted but not yet published should be designated as "in press" or "forthcoming"; authors should obtain written permission to cite such papers as well as verification that they have been accepted for publication. Information from manuscripts submitted but not accepted should be cited in the text as "unpublished observations" with written permission from the source.

Avoid citing a "personal communication" unless it provides essential information not available from a public source, in which case the name of the person and date of communication should be cited in parentheses in the text. For scientific articles, obtain written permission and confirmation of accuracy from the source of a personal communication.

Some but not all journals check the accuracy of all reference citations; thus, citation errors sometimes appear in the published version of articles. To minimize such errors, references should be verified using either an electronic bibliographic source, such as PubMed or print copies from original sources. Authors are responsible for checking that none of the references cite retracted articles except in the context of referring to the retraction. For articles published in journals indexed in MEDLINE, the ICMJE considers PubMed the authoritative source for information about retractions. Authors can identify retracted articles in MEDLINE by using the following search term, where pt in square brackets stands for publication type: Retracted publication [pt] in PubMed.

#### IV. A. 9. b. Reference Style and Format

The Uniform Requirements style for references is based largely on an American National Standards Institute style adapted by the NLM for its databases. Authors should consult NLM's Citing Medicine for information on its recommended formats for a variety of reference types. Authors may also consult sample references, a list of examples extracted from or based on Citing Medicine for easy use by the ICMJE audience; these sample references are maintained by NLM.

References should be numbered consecutively in the order in which they are first mentioned in the text. Identify references in text, tables, and legends by Arabic numerals in parentheses. References cited only in tables or figure legends should be numbered in accordance with the sequence established by the first identification in the text of the particular table or figure. The titles of journals should be abbreviated according to the style used in the list of

Journals Indexed for MEDLINE, posted by the NLM on the Library's Web site. Journals vary on whether they ask authors to cite electronic references within parentheses in the text or in numbered references following the text. Authors should consult with the journal to which they plan to submit their work.

#### IV. A. 10. Tables

Tables capture information concisely and display it efficiently; they also provide information at any desired level of detail and precision. Including data in tables rather than text frequently makes it possible to reduce the length of the text.

Type or print each table with double-spacing on a separate sheet of paper. Number tables consecutively in the order of their first citation in the text and supply a brief title for each. Do not use internal horizontal or vertical lines. Give each column a short or an abbreviated heading. Authors should place explanatory matter in footnotes, not in the heading. Explain all nonstandard abbreviations in footnotes, and use the following symbols, in sequence:

* , † , ‡ , § , ¶ , ¶ , ** , †† , ††† , §§ , |||| , §§ , etc.

Identify statistical measures of variations, such as standard deviation and standard error of the mean.

Be sure that each table is cited in the text.

If you use data from another published or unpublished source, obtain permission and acknowledge that source fully.

Additional tables containing backup data too extensive to publish in print may be appropriate for publication in the electronic version of the journal, deposited with an archival service, or made available to readers directly by the authors. An appropriate statement should be added to the text to inform readers that this additional information is available and where it is located. Submit such tables for consideration with the paper so that they will be available to the peer reviewers.

#### IV. A. 11. Illustrations (Figures)

Figures should be either professionally drawn and photographed, or submitted as photographic-quality digital prints. In addition to requiring a version of the figures suitable for printing, some journals now ask authors for electronic files of figures in a format (for example, JPEG or GIF) that will produce high-quality images in the Web version of the journal; authors should review the images of such files on a computer screen before submitting them to be sure they meet their own quality standards.

For x-ray films, scans, and other diagnostic images, as well as pictures of pathology specimens or photomicrographs, send sharp, glossy, black-and-white or color photographic prints, usually 127 × 173 mm (5 × 7 inches). Although some journals redraw figures, many do not. Letters, numbers, and symbols on figures should therefore be clear and consistent throughout, and large enough to re-
main legible when the figure is reduced for publication. Figures should be made as self-explanatory as possible, since many will be used directly in slide presentations. Tites and detailed explanations belong in the legends—not on the illustrations themselves.

Photomicrographs should have internal scale markers. Symbols, arrows, or letters used in photomicrographs should contrast with the background.

Photographs of potentially identifiable people must be accompanied by written permission to use the photograph.

Figures should be numbered consecutively according to the order in which they have been cited in the text. If a figure has been published previously, acknowledge the original source and submit written permission from the copyright holder to reproduce the figure. Permission is required irrespective of authorship or publisher except for documents in the public domain.

For illustrations in color, ascertain whether the journal requires color negatives, positive transparencies, or color prints. Accompanying drawings marked to indicate the region to be reproduced might be useful to the editor. Some journals publish illustrations in color only if the author pays the additional cost.

Authors should consult the journal about requirements for figures submitted in electronic formats.

### IV. A. 12. Legends for Illustrations (Figures)

Type or print out legends for illustrations using double spacing, starting on a separate page, with Arabic numerals corresponding to the illustrations. When symbols, arrows, numbers, or letters are used to identify parts of the illustrations, identify and explain each one clearly in the legend. Explain the internal scale and identify the method of staining in photomicrographs.

### IV. A. 13. Units of Measurement

Measurements of length, height, weight, and volume should be reported in metric units (meter, kilogram, or liter) or their decimal multiples.

Temperatures should be in degrees Celsius. Blood pressures should be in millimeters of mercury, unless other units are specifically required by the journal.

Journals vary in the units they use for reporting hematologic, clinical chemistry, and other measurements. Authors must consult the Information for Authors of the particular journal and should report laboratory information in both local and International System of Units (SI). Editors may request that authors add alternative or non-SI units, since SI units are not universally used. Drug concentrations may be reported in either SI or mass units, but the alternative should be provided in parentheses where appropriate.

### IV. A. 14. Abbreviations and Symbols

Use only standard abbreviations; use of nonstandard abbreviations can be confusing to readers. Avoid abbreviations in the title of the manuscript. The spelled-out abbreviation followed by the abbreviation in parenthesis should be used on first mention unless the abbreviation is a standard unit of measurement.

### IV. B. Sending the Manuscript to the Journal

An increasing number of journals now accept electronic submission of manuscripts, whether on disk, as an e-mail attachment, or by downloading directly onto the journal's Web site. Electronic submission saves time and money and allows the manuscript to be handled in electronic form throughout the editorial process (for example, when it is sent out for review). For specific instructions on electronic submission, authors should consult the journal's Instructions for Authors.

If a paper version of the manuscript is submitted, send the required number of copies of the manuscript and figures; they are all needed for peer review and editing, and the editorial office staff cannot be expected to make the required copies.

Manuscripts must be accompanied by a cover letter, which should include the following information.

* A full statement to the editor about all submissions and previous reports that might be regarded as redundant publication of the same or very similar work. Any such work should be referred to specifically and referenced in the new paper. Copies of such material should be included with the submitted paper to help the editor address the situation.

* A statement of financial or other relationships that might lead to a conflict of interest, if that information is not included in the manuscript itself or in an authors' form.

* A statement that the manuscript has been read and approved by all the authors, that the requirements for authorship as stated earlier in this document have been met, and that each author believes that the manuscript represents honest work if that information is not provided in another form (see below).

* The name, address, and telephone number of the corresponding author, who is responsible for communicating with the other authors about revisions and final approval of the proofs, if that information is not included in the manuscript itself.

The letter should give any additional information that may be helpful to the editor, such as the type or format of article in the particular journal that the manuscript represents. If the manuscript has been submitted previously to another journal, it is helpful to include the previous editor's and reviewers' comments with the submitted manuscript, along with the authors' responses to those comments. Editors encourage authors to submit these previous
communications. Doing so may expedite the review process.

Many journals now provide a presubmission checklist to help the author ensure that all the components of the submission have been included. Some journals now also require that authors complete checklists for reports of certain study types (for example, the CONSORT checklist for reports of randomized, controlled trials). Authors should look to see if the journal uses such checklists, and send them with the manuscript if they are requested.

Letters of permission to reproduce previously published material, use previously published illustrations, report information about identifiable persons, or to acknowledge people for their contributions must accompany the manuscript.

## V. REFERENCES

### A. References Cited in This Document

1. Davidoff F, for the CSE Task Force on Authorship. Who's the author? Problems with biomedical authorship, and some possible solutions. Science Editor. 2000;23: 111-9.

2. Yank V, Rennie D. Disclosure of researcher contributions: a study of original research articles in *The Lancet*. Ann Intern Med. 1999;130:661-70.

3. Flanagin A, Fontanarosa PB, DeAngelis CD. Authorship for research groups. JAMA. 2002;288:3166-8.

4. Godlee F, Jefferson T. Peer Review in Health Sciences. London: BMJ Books; 1999.

5. http://www.wma.net/e/policy/b3.htm (accessed June 26, 2009).

6. Rochon PA, Gurwitz JH, Cheung CM, Hayes JA, Chalmers TC. Evaluating the quality of articles published in journal supplements compared with the quality of those published in the parent journal. JAMA. 1994;272:108-13.

7. Pitkin RM, Branagan MA, Burmeister LF. Accuracy of data in abstracts of published research articles. JAMA. 1999;281:1110-1.

### B. Other Sources of Information Related to Biomedical Journals

World Association of Medical Editors (WAME)

Council of Science Editors (CSE)

European Association of Science Editors (EASE)

Cochrane Collaboration

Committee on Publication Ethics (COPE)

EQUATOR NETWORK http://www.equator-network.org

## VI. ABOUT THE INTERNATIONAL COMMITTEE OF MEDICAL JOURNAL EDITORS

The ICMJE is a group of general medical journal editors whose participants meet annually and fund their work on the Uniform Requirements for Manuscripts. The

ICMJE invites comments on this document and suggestions for agenda items.

## VII. AUTHORS OF THE UNIFORM REQUIREMENTS FOR MANUSCRIPTS SUBMITTED TO BIOMEDICAL JOURNALS

The ICMJE participating journals and organizations and their representatives who approved the revised Uniform Requirements for Manuscripts in April 2010 include *Annals of Internal Medicine*, *British Medical Journal*, *Canadian Medical Association Journal*, *China Medical Journal*, *Croatian Medical Journal*, *Journal of the American Medical Association*, *Nederlands Tijdschrift voor Geneeskunde* (*The Dutch Medical Journal*), *New England Journal of Medicine*, *New Zealand Medical Journal*, *The Lancet*, *The Medical Journal of Australia*, *Revisia Médica de Chile*, *Tidsskrift for Den Norske Legeforening* (*The Journal of the Norwegian Medical Association*), *Ugeskrift for Laeger* (*Journal of the Danish Medical Association*), the U.S. NLM, and the World Association of Medical Editors.

## VIII. USE, DISTRIBUTION, AND TRANSLATION OF THE UNIFORM REQUIREMENTS

Users may print, copy, and distribute this document without charge for not-for-profit, educational purpose. The ICMJE does not stock paper copies (reprints) of this document.

The ICMJE policy is for interested organizations to link to the official English language document at www.ICMJE.org. The ICMJE does not endorse posting of the document on Web sites other than that of the ICMJE.

The ICMJE welcomes organizations to reprint or translate this document into languages other than English for nonprofit purposes. However, the ICMJE does not have the resources to translate, back-translate, or approve reprinted or translated versions of the document. Thus, any translations should prominently include the following statement: "This is a (reprint /insert name language name) language translation) of the ICMJE Uniform Requirements for Manuscripts Submitted to Biomedical Journals. (insert name of organization) prepared this translation with support from (insert name of funding source, if any). The ICMJE has neither endorsed nor approved the contents of this reprint/translation. The ICMJE periodically updates the Uniform Requirements, so this reprint/translation prepared on (insert date) may not accurately represent the current official version at www.ICMJE.org. The official version of the Uniform Requirements for Manuscripts Submitted to Biomedical Journals is located at www.ICMJE.org."

We do not require individuals or organizations that reprint or translate the Uniform Requirements for Manuscripts Submitted to Biomedical Journals to obtain formal, written permission from the ICMJE. However, the ICMJE requests that such individuals or organizations provide the ICMJE secretariat with the citation for that reprint or
translation so that the ICMJE can keep a record of such
versions of the document.

IX. INQUIRIES

Before sending an inquiry, please consult Frequently
Asked Questions at www.icmje.org, as this section of the
Web site provides answers to the most commonly asked
questions.

Inquiries about the Uniform Requirements should be
sent to the ICMJE Secretariat office by using the "Contact
ICMJE" link on the home page of www.icmje.org. Please
do not direct inquiries about individual studies, individual
journal styles, or individual journal policies to the ICMJE
secretariat office. The ICMJE does not archive individual
journal contact information. Manuscripts intended for
submission to a journal must be sent directly to the jour-
nal, not to the ICMJE.
ANNEX 5
GLOSSARY

<table><tr><td>ADS</td><td>Astrophysics Data System</td></tr><tr><td>AERES</td><td>Agence d'Évaluation de la Recherche et de l'Enseignement Supérieur (National evaluation agency for research and higher education)</td></tr><tr><td>CNRS</td><td>Centre National de la Recherche Scientifique (French national centre for scientific research)</td></tr><tr><td>CEA</td><td>Commissariat à l'Énergie Atomique (Atomic Energy Commission)</td></tr><tr><td>CHU</td><td>Centre Hospitalier Universitaire (medical teaching hospital)</td></tr><tr><td>CNU</td><td>Conseil National des Universités (National council of universities)</td></tr><tr><td>CoNRS</td><td>Comité National de la Recherche Scientifique (National committee for scientific research)</td></tr><tr><td>CPU</td><td>Conférence des Présidents d'Université (The Conference of University Presidents)</td></tr><tr><td>CR (2, 1)</td><td>Chargé de Recherche (Researcher, 2nd, 1st class)</td></tr><tr><td>CREST</td><td>Centre de Recherche en Économie et Statistiques (Centre for research in economy and statistics)</td></tr><tr><td>DR (2,1,E)</td><td>Director of research (2nd, 1st, exceptional class)</td></tr><tr><td>EPIC</td><td>Établissement Public à caractère Industriel et Commercial (Public industrial and commercial establishment)</td></tr><tr><td>EPST</td><td>Établissement Public à caractère Scientifique et Technologique (Public scientific and technical research establishments)</td></tr><tr><td>ERC</td><td>European Research Council</td></tr><tr><td>ESO</td><td>European Southern Observatory</td></tr><tr><td>IF</td><td>Impact Factor</td></tr><tr><td>G</td><td>Egghe's index</td></tr><tr><td>H</td><td>Hirsch's index</td></tr><tr><td>INIST</td><td>Institut de l'Information Scientifique et Technique (Institute for Scientific and Technical Information)</td></tr><tr><td>INRA</td><td>Institut National de Recherche Agronomique (National institute for agronomic research)</td></tr><tr><td>INSERM</td><td>Institut National de la Santé et de la Recherche Médicale (National institute of health and medical research)</td></tr></table>
IRD Institut de Recherche pour le Développement
(Institute of research for development)

ISI Institute for Scientific Information

IUF Institut Universitaire de France
(University institute of France)

JCR Journal Citation Reports

LRU Loi relative aux Libertés et Responsabilités des Universités
(Universities' Freedom and Responsibilities law)

MDC or MCF Maître de Conférences
(Lecturer)

NASA National Aeronautics and Spatial Administration

OST Observatoire des Sciences et des Techniques
(Science and techniques observatory)

PNAS Proceedings of the National Academy of Sciences

PR (2,1,E) Professor (2nd, 1st, exceptional class)

SCOPUS Elsevier database

SHS Social and Human Sciences

UFR Unité de Formation et de Recherche
(Teaching and Research Unit)

UMR Unité Mixte de Recherche
(Mixed Research Unit, University and CNRS)