Bates T, Anić A, Marušić M, Marušić A. Authorship Criteria and Disclosure of ContributionsComparison of 3 General Medical Journals With Different Author Contribution
Forms. JAMA. 2004;292(1):86-88. doi:10.1001/jama.292.1.86
Author Affiliations: Zagreb University School of Medicine, Zagreb, Croatia.
Context A number of general medical journals and the International Committee
of Medical Journal Editors (ICMJE) request authors to disclose their contributions.
Little is known about the effect of journal policies on authors' disclosure
of their contributions.
Objective To determine the number of named authors who do not meet ICMJE criteria
for authorship, according to their published contributions, in 3 medical journals
with different contribution disclosure practices.
Design Observational study of authors' contributions in research articles published
in 2002 in Annals of Internal Medicine (n = 72), BMJ (n = 107), and JAMA (n = 81). BMJ asks authors to describe research contributions in their own words; Annals asks authors to choose from a list of coded contributions;
and JAMA uses a structured checklist with instructions on contributions
that qualify for ICMJE authorship criteria. Honorary authorship was defined
as the lack of contribution from the first ICMJE criterion (study conception
and design, or acquisition of data, or analysis and interpretation of data)
and/or second (drafting the article or critical revision for important intellectual
content) ICMJE criterion.
Results According to authors' published contributions, the number of honorary
authors was highest in Annals (121/562 authors, 21.5%),
followed by BMJ (46/482, 9.5%), and JAMA (3/641,
0.5%) (χ22 = 146.67, P<.001).
The number of articles with honorary authors was 60% in Annals, 21% in BMJ, and 4% in JAMA. Honorary
authors had fewer published contributions than authors who met ICMJE criteria
and were positioned more toward the end of the byline. Honorary authors either
lacked contributions for both ICMJE criteria (10% in Annals and 22% in BMJ) or contributions to the second
ICMJE criterion (75% in Annals, 67% in BMJ, and 2 out of 3 in JAMA).
Conclusions General medical journals differed in prevalence of honorary authors
according to published research contributions of named authors. Different
authorship/contributorship policies and procedures should be explored as a
possible explanation for the differences in contributions disclosed by authors
among these journals.
Although authorship of biomedical publications establishes credit and
responsibility for reported research to readers, authors, and editors alike,
it is burdened by misunderstandings and misuses.1- 3 In
response to the 1997 proposal to acknowledge research contributions in journal
articles1 as a way to limit irresponsible authorship,
contribution disclosure has been introduced in some general medical journals.
The most recent revision from the Uniform Requirements for Manuscripts Submitted
to Biomedical Journals of the International Committee of Medical Journal Editors
(ICMJE) encourages editors to develop and implement contributorship policies.4 The ICMJE defines authorship as (1) substantial contribution
to the 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. Studies across a variety of journals
show that 20% to 50% of authors do not satisfy all 3 ICMJE criteria and may
be honorary authors.2,5- 8
To assess whether 6 years of contribution disclosure practice has had
an effect on the number of authors whose published contributions do not meet
ICMJE criteria for authorship, we analyzed published statements of authors'
contributions in 3 major general medical journals. We studied journals with
3 different contribution disclosure practices: BMJ,
which asks authors to describe research contributions in their own words9; Annals of Internal Medicine, which
asks authors to choose from a list of contributions and associated letter
codes and mark these codes on an author's form10;
and JAMA, which requires authors to complete a structured checklist that
itemizes how many contributions qualify for ICMJE authorship criteria.11
We analyzed research articles published in 2002: "Articles" in Annals (n = 72), "Papers" in BMJ (n
= 107), and "Original Contributions" (n = 81) in JAMA. As Annals is published every other week, only the first and third monthly
issues of JAMA and BMJ were analyzed. Paper editions
were analyzed, except when the author contribution information was available
only on the Web (all Annals articles since April
16, 2002, and 67 [61%] BMJ articles). Articles without
disclosed author contributions (6 "Drug Points" in BMJ and
3 case reports in JAMA) were excluded. Stated author's contributions were
categorized and entered into a database jointly by 2 authors (T.B. and A.A.);
the database was independently checked against the articles by a third author
Contributions were coded into 11 categories: (1) conception and design
of the study, (2) analysis and interpretation of data, (3) collection or assembly
of data, (4) statistical expertise, and (5) provision of study material or
patients (categories 1-5 are eligible for authorship according to the first
ICMJE criterion); (6) drafting of the article or part of the article and (7)
critical revision of the article for important intellectual content (categories
6 and 7 are eligible for the second ICMJE criterion); (8) obtaining funding;
(9) administrative, technical, or logistic support; (10) guarantor of the
study; and (11) study supervision or coordination. As the information on the
third ICMJE criterion (approval of the version of the manuscript to be published)
was rarely stated, we assumed that all authors fulfilled this criterion.5Honorary author was thus
defined as a person named in the article as an author whose published contributions
did not meet both the first and second ICMJE criteria for authorship.
Based on the assumption that the number of articles with honorary authors
would decrease by half from 19% reported in 1996,2 we
estimated a sample size of 80 articles in each group with β = .20 and
2-tailed α = .05. Differences in proportions were tested with χ2 tests. The Kruskal-Wallis test and a subsequent Wilcoxon test were
used to the compare number of contributions, number of authors, and their
byline position. Bonferroni correction was used for multiple comparisons.
All statistical tests and 95% confidence intervals were calculated using Medcalc
statistical software (Medcalc, Mariakerke, Belgium).
As shown in Table 1, JAMA
had the fewest (0.5%) honorary authors (ie, authors whose published contributions
did not meet minimum criteria for authorship), compared with 9.5% in BMJ and 21.5% in Annals (χ22 = 146.67, P<.001), as well
as the fewest articles with honorary authorship (χ22 =
64.54, P<.001). An honorary author was never the
first author in the byline. In BMJ and Annals, 11 and 5 articles, respectively, had honorary authors as the
last person in the byline. Compared with authors whose published contribution
met authorship criteria, honorary authors were placed more toward the end
of the byline (Annals, z score
= 5.494, P<.001; BMJ, z score = 4.398, P<.001), and
articles with honorary authors had longer bylines (Annals, z score = −3.932, P<.001; BMJ, z score
= 2.798, P = .005). BMJ articles,
either with or without honorary authors, had significantly fewer authors than Annals or JAMA (z score = 6.217
vs Annals, P<.001; z score = 6.743 vs JAMA, P<.001).
The number of honorary authors per article did not differ among the journals
(mode = 1 for all), but the number of contributions per honorary author was
significantly fewer than that for authors whose published contributions met
authorship criteria (Annals, z score = −13.627, P<.001; BMJ, z score = −9.090, P<.001). Most honorary authors did not have stated contributions
to meet the second ICMJE criterion (ie, drafting or critically revising the
manuscript) (Table 1).
We separately analyzed articles with a group as the author in the byline. BMJ had 2 such articles: 1 had 14 honorary authors out
of 20 listed, all lacking contributions from the second ICMJE criterion. In JAMA,
2 out of 5 articles with group authorship were authored by the same study
group members and had 8 honorary authors each, all lacking contributions from
the second ICMJE criterion.
Although limited by its cross-sectional design and selection of journals,
our study showed significant differences in the number of authors whose published
contributions did not meet authorship criteria in research articles published
in 3 general medical journals. In comparison with data from studies conducted
before journals instituted author contribution disclosure policies,2,12,13 the proportion of
authors whose published contributions did not meet authorship criteria, ie,
honorary authors, in this study did not change in Annals but decreased in BMJ, from 29% reported in
1998 to 10%, and decreased in JAMA, from 18% in 1996 to 0.5%.
The current differences among 3 journals in the number of authors whose
published contributions did not meet ICMJE authorship criteria could be explained
by many factors, including journal size, type of research published, and origin
of authors, as well as different authorship/contribution policies, procedures,
and forms. The Author's Form in Annals asks individual
authors to choose from 10 research contribution codes associated with letters a through j and then mark these
letter codes in a space provided under author information; ICMJE criteria
are stated in an Information for Authors guide but not directly in the Author's
Form, which is located on a separate Web page. BMJ's
Guidelines for Authors (Authorship and Contributorship section) cite ICMJE
criteria and repeat the ICMJE statement that "participation solely in the
acquisition of funding or the collection of data does not justify authorship."
In addition, the BMJ guideline explains the concept
of contributorship and asks authors to describe research contributions in
their own words. JAMA's form for "Authorship Responsibility,
Financial Disclosure, Copyright Transfer, and Acknowledgment" lists the ICMJE
authorship criteria and includes a structured checklist of specific contributions
with the number of contributions qualifying for each authorship criterion.
Annals and JAMA had similar median numbers
of authors per article (n = 7), but almost double that in BMJ. This suggests that the size of the byline is not associated with
the type of contribution disclosure but perhaps with other characteristics
of the journals, such as types of research studies reported or geographic
origin of authors. In our study, 30% and 28% of research articles published
by JAMA and Annals, respectively, were randomized
controlled trials, compared with 19% in BMJ. There
were also differences in geographic origin of authors: 64% and 73% of authors
in Annals and JAMA, respectively, were from the
United States and 63% of authors in BMJ were from
the United Kingdom. A common finding for all journals was that most honorary
authors did not meet the second ICMJE criterion on contribution to manuscript
writing or critical revision.
In conclusion, after several years of contribution disclosure practices
in 3 general medical journals, the number of authors with published contributions
that did not meet authorship criteria differs among these journals. Future
research should address how these differences may be related to different
authorship/contribution policies and procedures as well as different forms
used to collect this information.