All persons listed as authors should qualify for authorship (see 5.1, Ethical and Legal Considerations, Authorship Responsibility, and 5.1.2, Ethical and Legal Considerations, Authorship Responsibility, Guest and Ghost Authors). Order of authorship should be determined by the authors (see 5.1.5, Ethical and Legal Considerations, Authorship Responsibility, Order of Authorship). According to the International Committee of Medical Journal Editors,2
Authorship credit should be based on 1) substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data; 2) drafting the article or revising it critically for important intellectual content; and 3) final approval of the version to be published. Authors should meet conditions 1, 2, and 3.
Some journals (including JAMA, several of the Archives Journals, BMJ, and Lancet) may publish authors' specific contributions. See 2.10.5, Acknowledgment Section, Author Contributions.
Persons who made other contributions but who do not qualify for authorship may be listed in the Acknowledgment section (see 2.10.14, Acknowledgment Section, Additional Contributions), with their permission (see 5.2, Ethical and Legal Considerations, Acknowledgments).
If an author requests that his or her name be withheld from publication, this should be allowed only in rare cases with compelling justification. In those rare cases, the author must meet the authorship criteria, but the byline may reflect the author’s desire for anonymity (see 5.1.3, Ethical and Legal Considerations, Authorship Responsibility, Unsigned Editorials, Anonymous Authors, Pseudonymous Authors).
See also 2.2.4, Multiple Authors, Group Authors.