Do Medical Journals Provide Clear and Consistent Guidelines on Authorship?

Elizabeth Wager, MA

In This Article


The 234 instructions reviewed came from 9 ICMJE members, 117 WAME members, and 108 non-WAME, Medline-listed journals; 100 of these (41%) did not include any guidance about authorship. Of the other 134 journals, 68 (ie, 29% of the total and 51% of those that mentioned authorship) based their guidance on the ICMJE criteria. Twenty-six journals (11%) included a general reference or link to the ICMJE Web site and 25 (11%) included direct quotations from the ICMJE authorship guidance, while 17 (7%) contained paraphrased versions of the ICMJE criteria ( Table ). Thirty-three journals (14%) proposed their own criteria for authorship that differed, in some way, from the ICMJE criteria, while a further 33 (14%) did not provide guidance about authorship except for stating that all authors must approve the final version of the submitted manuscript. Eight journals (3%) set limits on the number of authors who could be listed (which varied from 6 to 12, with a median of 7.5 for original studies).

Of the 26 journals that cited the ICMJE URM, 13 provided a reference to the latest published version or Web site, 9 cited a previous version, and 4 mentioned the guidelines without providing a reference or link to them. Similarly, of the 25 journals whose instructions quoted from the ICMJE authorship guidelines, 16 quoted the most recent version, but 9 quoted an outdated version. (The URM were updated in 2001 when data acquisition was added as one of the activities that may qualify for authorship; they were further revised in 2003 but without any substantive changes to the 3 authorship criteria.[8])

The ICMJE encourages editors "to develop and implement a contributorship policy" (ie, to list individuals' contributions to a project as well as their names and affiliations), yet only 21 (9%) of the 234 journals reviewed required such information (despite 29% of the journals claiming to endorse the ICMJE's requirements).

Of the 9 journals edited by members of the ICMJE, 5 quoted directly from the most recent version of the ICMJE authorship guidance, 2 cited it or provided links to the ICMJE Web site, 1 paraphrased the ICMJE criteria, and 1 referenced the ICMJE statement but noted that it "has some serious flaws" and therefore proposed guidance of its own.[5]

Journals whose editors were members of WAME were significantly more likely to mention authorship in their instructions (82/117 = 70%) than those who were not members (43/108 = 40%) (chi-square test, P < .001).

1. No guidance. Journals that gave no guidance about authorship tended to publish short instructions to contributors that focused on technical requirements for formatting and submission. These short instructions concentrated on manuscript preparation and were silent on topics such as the disclosure of competing interests and the requirement for ethical review of clinical trials. However, such instructions often included detailed information about how references should be formatted and illustrations prepared.

2. General reference to ICMJE URM. Journals in this category included broad statements in their instructions such as: "Submissions should be prepared according to the Uniform Requirements" or "Authors should conform to the general guidelines laid out in Uniform Requirements for Manuscripts Submitted to Biomedical Journals."[1]

Several journals cited outdated versions of the ICMJE document, for example:

"The manuscript should conform to the guidelines in Uniform Requirements for Manuscripts Submitted to Biomedical Journals, 5th edition, prepared by the ICMJE and published in N Engl J Med. 1997;336:309-315." and "The requirements of the journal are in accordance with the ICMJE Uniform Requirements for Manuscripts Submitted to Biomedical Journals (BMJ. 1991;302:338-341)."

Four journals used vague wording such as "Current Surgery's Instructions to Authors follow many of the standards included in the Uniform Requirements for Manuscripts Submitted to Biomedical Journals" or implied that the URM applied only to format, eg, "We ask that the manuscript is no longer than 2500 words and that the style conforms to that detailed in Uniform Requirements for Manuscripts Submitted to Biomedical Journals."

3. Explicit use of ICMJE authorship criteria. Some instructions mentioned the ICMJE authorship criteria but did not list them, simply stating, for example, that authors should ensure that they have "met the criteria for authorship established by the ICMJE." Others quoted the full authorship section from the URM (see appendix / text box). Several journals quoted the pre-2001 criteria, which did not include data acquisition as a qualifying activity for authorship.

4. Paraphrase of ICMJE. These instructions followed the spirit of the ICMJE criteria but did not adopt the exact wording. For example, "Authorship credit should be based on substantial contribution to conception and design, execution, or analysis and interpretation of data. All authors should be involved in drafting the article or revising it critically for important intellectual content, and must have read and approved the final version of the manuscript." Another journal required authors to "state that they are responsible for the research that they have designed and carried out; that they participated in drafting and revising the manuscript submitted, which they approve in its contents."

5. Journals' own authorship criteria. Some journals provided their own criteria for determining authorship. These ranged from short statements such as "Each person listed as an author is expected to have participated in the study to a significant extent" to much more extensive guidance. For example, The Physiologist provides guidance that goes beyond that of the ICMJE:

"The Editors of the journals of the American Physiological Society (APS) expect each author to have made an important scientific contribution to the study and be thoroughly familiar with the original data. The Editors also expect each author to have read the complete manuscript and to take responsibility for the content and completeness of the manuscript and to understand that if the paper, or part of the paper, is found to be faulty or fraudulent, that he/she shares responsibility with his/her coauthors."

The ICMJE URM gives no guidance on how to determine the order in which authors or contributors are listed, simply stating that this should be "a joint decision of the co-authors." Instructions for The Physiologist state that authors should be listed "in the order of importance of their contribution to the study." Four other journals allowed joint first authorship. One stated that "if two authors have contributed equally to the work, this should be noted under the corresponding author information" while another allowed up to 3 authors to be "designated as 'first authors who contributed equally to this work' if the contributions of those individuals essentially constituted the majority of the work on the project." This journal also allowed the category "mentors who contributed equally to this work" to be used for "senior investigators, clinicians, or directors who provided the support and mentorship necessary for the success of the work."

Eight journals limited the number of authors who could be listed. One stated that "The number of authors on a manuscript should not exceed 10. Manuscripts exceeding this limit will be returned without review." Others were less draconian, stating, for example, "the number of authors of each paper should not be more than twelve; a greater number requires justification." Some journals set different limits for different types of article, for example up to 4 authors for case reports and 6 for experimental studies.

Rather than setting limits on the number of authors, some journal instructions encouraged inclusion. One stated "we ... want assurance that there is no one else who fulfils the criteria but has not been included as an author"; while another stated "anyone who makes significant intellectual contribution must be given authorship."

The final criterion of the ICMJE URM is that all authors should have approved the final version of the publication. This was the most frequently stated requirement among journals that provided no other guidance about authorship. Many journals require a statement in the covering letter that the submission has been approved by all authors. One set of instructions noted "It is taken for granted that the publication has been approved by all participating authors" and another that "manuscripts are accepted for review with the understanding that ... its submission for publication has been approved by all of the authors." Another stated that "submission is a representation that all authors have personally reviewed and given final approval of the version submitted."


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