The trend in modern physics is clear: the best science of all is th...
Between 2000 and 2016, the overall number of authors (excluding Phy...
It's quite interesting to read the authors' replies (you can find t...
It's curious to note that the number of published articles per year...
Numerous authors, particularly in the field of medical sciences, de...
ECOLOGY Pathogen could wipe
out New Zealand’s oldest tree
species p.177
PSYCHOLOGY How a
questionable personality
quiz went global p.176
HISTORY At last, a
definitive biography of
Helmholtz p.175
SPACE Astrophysics’ long
relationship with the
military p.173
The scientists who publish
a paper every five days
To highlight uncertain norms in authorship, John P. A. Ioannidis, Richard Klavans
and Kevin W. Boyack identified the most prolific scientists of recent years.
A
uthorship is the coin of scholar-
ship — and some researchers are
minting a lot. We searched Scopus
for authors who had published more than
72papers (the equivalent of one paper
every 5 days) in any one calendar year
between 2000 and 2016, a figure that many
would consider implausibly prolific
1
. We
found more than 9,000 individuals, and
made every effort to count only ‘full papers’
— articles, conference papers, substantive
comments and reviews — not editorials,
letters to the editor and the like. We hoped
that this could be a useful exercise in under-
standing what scientific authorship means.
We must be clear: we have no evidence
that these authors are doing anything inap-
propriate. Some scientists who are members
of large consortia could meet the criteria for
authorship on a very high volume of papers.
Our findings suggest that some fields or
research teams have operationalized their
own definitions of what authorship means.
The vast majority of hyperprolific authors
(7,888 author records, 86%) published
in physics. In high-energy and particle
physics, projects are done by large inter-
national teams that can have upwards of
1,000members. All participants are listed
as authors as a mark of membership of the
team, not for writing or revising the papers.
We therefore excluded authors in physics.
Of what remained, 909 author records
were Chinese or Korean names. Because
Scopus disambiguates Chinese and Korean
names imperfectly, these may have wrongly
combined distinct individuals. For 2016
(when disambiguation had improved for
Chinese and Korean names), at least
ILLUSTRATION BY DAVID PARKINS
13 SEPTEMBER 2018 | VOL 561 | NATURE | 167
COMMENT
12, and possibly more than 20, authors
based in China were hyperprolific, the larg-
est number from any country that year. We
believe that this could be connected to Chi-
nese policies that reward publication with
cash or to possible corruption
2,3
.
Because of the disambiguation issues, we
excluded these names from further analysis,
as well as group names and cases in which
we found errors (such as journalistic news
items misclassified as full articles), duplicate
entries, or conference papers misassigned to
an organizer.
This left 265 authors (see Supplementary
Information). The number of hyperprolific
authors (after our exclusions) grew about
20-fold between 2001 and 2014, and then
levelled off (see ‘Hyperprolific authors pro-
liferate’). Over the same period, the total
number of authors increased by 2.5-fold.
We e-mailed all 265 authors asking for
their insights about how they reached this
extremely productive class. The 81 replies
are provided in the Supplementary Informa-
tion. Common themes were: hard work; love
of research; mentorship of very many young
researchers; leadership of a research team, or
even of many teams; extensive collaboration;
working on multiple research areas or in core
services; availability of suitable extensive
resources and data; culmination of a large
project; personal values such as generosity
and sharing; experiences growing up; and
sleeping only a few hours per day.
About half of the hyperprolific authors
were in medical and life sciences (medicine
n = 101, health sciences n = 11, brain n =17,
biology n = 6, infectious diseases n=3). When
we excluded conference papers, almost two-
thirds belonged to medical and life sciences
(86/131). Among the 265, 154authors pro-
duced more than the equivalent of one paper
every 5 days for 2 or more calendar years; 69
did so for 4 or more calendar years. Papers
with 10–100 authors are common in these
CVs, especially in medical and life sciences,
but papers with the hundreds of authors seen
in particle physics are uncommon.
Materials scientist Akihisa Inoue, former
president of Tohoku University in Japan and
a member of multiple prestigious academies,
holds the record. He met our definition of
being hyperprolific for 12 calendar years
between 2000 and 2016. Since 1976, his
name appears on 2,566 full papers indexed
in Scopus. He has also retracted seven papers
found to be self-duplications of previously
published work
4
. We searched for news
articles in Google detailing retractions for
the next 20 most hyperprolific authors and
found only one other author (Jeroen Bax) to
have one retracted paper.
The 265 hyperprolific authors worked in
37 countries, with the highest number in the
United States (n = 50), followed by Germany
(n = 28) and Japan (n = 27). The propor-
tion from the United States (19%) is roughly
similar to its share of published science. Ger-
many and Japan are over-represented. There
were disproportionally more hyperprolific
authors in Malaysia (n = 13) and Saudi Ara-
bia (n = 7), countries both known to incentiv-
ize publication with cash rewards
5
.
Hyperprolific authors also tended to cluster
in particular institutions, often as part of a
common study. For example, Erasmus Uni-
versity Rotterdam in the Netherlands had
nine hyperprolific
authors, more than
any other institu-
tion. Seven of them
co-authored mostly
papers related to the
Rotterdam study,
a nearly 30-year-
old epidemiological
project, or its suc-
cessor Generation
R study, which have followed multiple health
parameters in thousands of older adults and
yielded thousands of publications. Five hyper-
prolific investigators from Harvard Univer-
sity in Cambridge, Massachusetts, also often
co-authored papers related to cohort studies.
Eleven hyperprolific authors across different
institutions were on one large cohort study,
the European Prospective Investigation on
Cancer and Nutrition; other large epidemio-
logical studies were also represented. Hyper-
prolific authors were also concentrated in
cardiology and crystallography.
These biological and medical disciplines
with many hyperprolific authors exhibit dif-
ferent patterns from those found in particle
and high-energy physics. Papers with hun-
dreds to thousands of authors are the norm
across a community of many thousands
of scientists working in projects based at
CERN, Europe’s particle-physics laboratory
near Geneva, Switzerland. In crystallogra-
phy, papers tend to have few co-authors. In
epidemiology and cardiology, long lists of
authors appear only in relationship to spe-
cific research teams that seem to have a tra-
dition of extensive authorship lists.
This raises the question of what
authorship entails. The US National Insti-
tutes of Health, for example, has guidelines
on the activities that qualify: actively super-
vising, designing and doing experiments,
and data acquisition and analysis outside
“very basic” work plus drafting the manu-
script. Collecting funds or distant mentor-
ship do not qualify. Most of the 6,000 authors
in a recent survey across many geographical
regions and disciplines felt that drafting a
paper, interpreting results and analysing data
should qualify for authorship, but attitudes
varied by region and field
6
.
AUTHORSHIP CRITERIA
Perhaps the most widely established
requirements for authorship are the
Vancouver criteria established by the Inter-
national Committee of Medical Journal
Editors in 1988. These specify that authors
must do all of four things to qualify: play a
part in designing or conducting experiments
or processing results; help to write or revise
the manuscript; approve the published ver-
sion; and take responsibility for the article’s
contents.
The International Committee of Medical
Journal Editors does not count supervision,
mentoring or obtaining funding as sufficient
for authorship. We did observe that some
authors seemed to become hyperprolific on
becoming full professors, department chairs
or both. It is common and perhaps expected
for scientists who assume leadership roles in
large centres to accelerate their productivity.
For example, clinical cardiologists publish
more papers after they assume director roles
(despite heavy clinical and administrative
duties). Occasionally, the acceleration is
stunning: at the peak of their productivity,
some cardiologists publish 10 to 80 times
more papers in one year compared with their
average annual productivity when they were
35–42 years old. There was also often a sharp
decrease after passing the chair to a succes-
sor. Another study noted similar patterns
two decades ago
7
.
One-third of the 81 authors identified
as hyperprolific in 2016 replied
when asked how often they met
each of 4 criteria established for
authorship of medical studies. Of the
27 responders, 19 admitted they had
not met at least 1 criterion more than
25% of the time. Eleven wrote that
they had not met two or more criteria
upwards of 25% of the time.
Substantial contributions to the
conception or design of the work;
or the acquisition, analysis or
interpretation of the data for the work
(9 of 27 met this criterion in less than
75% of their papers).
Drafting the work or revising it
critically for important intellectual
content (9 of 27 met this criterion in
less than 75% of their papers).
Final approval of the version to be
published (3 out of 27 met this criterion
in less than 75% of their papers).
Agreement to be accountable for all
aspects of the work (14 out of 27 met
this criterion in less than 75% of their
papers).
SURVEY
Criteria fulfilled?
“Whether and
how authorship
is justified
unavoidably
varies for each
author and
each paper, and
norms differ by
field.”
168 | NATURE | VOL 561 | 13 SEPTEMBER 2018
COMMENT
One unexpected result was that some
hyperprolific authors placed many publica-
tions in a single journal. Prominent in this
regard were Acta Crystallographica Section E:
Structure Reports Online (relaunched in 2014
as Section E: Crystallographic Communica-
tions, with brief structural data reports now
published in IuCrData) and Zeitschrift für
Kristallographie New Crystal Structures. Three
authors have each published more than 600
articles in the former (Hoong-Kun Fun, Seik
Weng Ng and Edward Tiekink); three authors
have each published more than 400 papers in
the latter (Karl Peters, Eva Maria Peters and
Edward Tiekink). Three other authors (Anne
Marie Api, Charlene Letizia, Sneha Bhatia)
published many papers in single supplement
issues of Food and Chemistry Toxicology
focused on reviews of fragrance materials.
Journals indexed in Scopus are generally
considered to be quality journals. The cita-
tion impact of hyperprolific authors was
usually high, but there was large variability:
with a median of 19,805 citations per author
(range: 380 to 200,439). The median num-
ber of full papers per hyperprolific author in
2000–2016 was 677; across all hyperprolific
authors, last author positions accounted for
42.5%, first author positions for 7.1%, and
single authorships for 1.4%. Across the years,
the median proportion of papers with mid-
dle author positions (that is, not a single,
first or last author) was 51%, but varied from
2.1% to 98.5% for individual authors.
Our work to identify hyperprolific authors
is admittedly crude. It is mainly intended to
raise the larger question of what authorship
entails. Whether and how authorship is jus-
tified unavoidably varies for each author
and each paper, and norms differ by field.
It is likely that sometimes authorship can be
gamed, secured through coercion or pro-
vided as a favour. We could not assess these
patterns in our data. We did not examine
contributorship statements
8
, which are not
archived in Scopus. Nevertheless, even con-
tributorship statements can be gamed and
might not be accurate.
Further work is needed to explore how
to best normalize these data and what is the
optimal level of normalization: for example,
adjusting for wide discipline, relatively nar-
row field and/or highly specific research team.
WHAT AUTHORS SAY
To better understand authorship norms, we
e-mailed a survey to the 81 hyperprolific
authors of 2016 (see Supplementary Infor-
mation). We asked whether they fulfilled
all four Vancouver criteria. Of the 27 who
completed the survey, most said they did
not (see ‘Survey’). Almost all the responders
were from US and European institutions.
The only two responders from elsewhere
stated that they failed Vancouver criteria
in most of their papers. It is likely that the
survey underestimates the proportion not
meeting Vancouver criteria.
Not all authors had approved the final
versions of their own papers, but all consid-
ered approval of the final version necessary
for authorship. Fifty-nine per cent (16 of 27)
said that they had contributed more than
any other listed author for 25 or more of the
papers they authored in 2016.
Responses to the question “What, in
your own words, do you think should be
required for authorship?” generally reflected
a requirement for “significant contributions”,
but also dissatisfaction with how authorship
was assessed. One scientist said, “I person-
ally don’t count them as ‘my papers’ and
don’t have them on my CV as such, as there is
a distinction between being a ‘named author’
versus a ‘consortium member’ authorship.”
Another observed that authorship was often
awarded for seniority, and another that bet-
ter distinctions were essential. “I think there
should be levels of authorship — and not
those implied by order!” It will be interest-
ing to monitor how innovations in assign-
ing credit, such as data citation or formal
author contribution taxonomies, could alter
authorship conventions. Authorship norms
can vary within each field and even within
each team. For example, some teams in epi-
demiology and cardiology apparently offer
authorship more generously; others stick to
stricter (and probably more appropriate)
authorship criteria. For a similar task and
contribution, one cohort study might credit
20 authors, another might give credit only
to 3 people or none. For example, genome-
wide studies typically include many dozens
of authors. As a dramatic counter-example,
one recent publication of a genome-wide
study had only one author
9
, and apparently
that researcher did the same amount of work
for which perhaps dozens would get author-
ship credit in similar papers spearheaded by
different teams. Some evidence suggests
that the increase in the average number of
authors per paper does not reflect so much
the genuine needs of team science as the
pressure to ‘publish or perish’
10
.
Widely used citation and impact metrics
should be adjusted accordingly. For instance,
if adding more authors diminished the credit
each author received, unwarranted multi-
authorship might go down. We found that
the 30 hyperprolific authors who seemed to
benefit the most from co-authorship num-
bered 6 cardiologists and 24 epidemiologists
(including those working on population
genetics studies). (For these scientists, the
ratio of their Hirsch H index to their co-
authorship-adjusted Schreiber H
m
index was
higher; see Supplementary Information.)
Overall, hyperprolific authors might
include some of the most energetic and excel-
lent scientists. However, such modes of pub-
lishing might also reflect idiosyncratic field
norms, to say the least. Loose definitions of
authorship, and an unfortunate tendency
to reduce assessments to counting papers,
muddy how credit is assigned. One still needs
to see the total publishing output of each sci-
entist, benchmarked against norms for their
field. And of course, there is no substitute for
reading the papers and trying to understand
what the authors have done.
John P. A. Ioannidis is a professor of
medicine at the Meta-Research Innovation
Center at Stanford (METRICS), Stanford
University, California, USA. Richard
Klavans and Kevin W. Boyack are
researchers at SciTech Strategies in
Philadelphia, Pennsylvania, and
Albuquerque, New Mexico, USA.
e-mail: jioannid@stanford.edu
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(2015).
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Supplementary Information accompanies this
Comment online (see go.nature.com/2phadg2).
HYPERPROLIFIC
AUTHORS PROLIFERATE
Numbers of authors with more than 72 papers
a year increased dramatically over time.
2002
2008
2016
= 1 author
4
39
81
SOURCE: J. P. A. IOANNIDIS, R. KLAVANS & K. W. BOYACK
13 SEPTEMBER 2018 | VOL 561 | NATURE | 169
COMMENT
The trend in modern physics is clear: the best science of all is the most collaborative as can be seen by the evolution of the number of authors on Nobel Prize winning discovery papers.
Some, for instance the philosoph Agnes Callard, argue that true thinking in any case can only happen with others. Collaboration trumps the genius.
Hmmmmm. Yet this sounds a bit like "the hardest grinder will always win", but then Cal Newport and others point out that this is not the way productivity works. Usually, the longer you work continuously, the more errors you do, the less original you become etc. Focus and high concentration take a toll on the brain, or better, on the brain's supply with glucose, oxygen etc.
So I doubt the explaination by the authors is true.
And, scanning their answers, it seems most seem to work within large collaborative teams, just like in physics (but precisely not in physics, so included in the statistics).
It's quite interesting to read the authors' replies (you can find them [here](https://media.nature.com/original/magazine-assets/d41586-018-06185-8/16110186)), one common note in a lot of the replies is the way the number of daily working hours are being counted. Multiple authors mentioned that they work 2 to 3 times more hours per day than a regular job and so in practice they are publishing a paper every 10 to 15 "normal working hours" days or 2/3 papers a month.
It's curious to note that the number of published articles per year in 2016, doesn't reflect the number of hyperprolific authors in the cases of India and the United Kingdom.
Between 2000 and 2016, the overall number of authors (excluding Physics) experienced a 2.5-fold increase. The slight decrease observed in 2015-2016 can be attributed to the exclusion of authors with Chinese and Korean names, as these recent years have seen a rise in the number of Chinese hyperprolific authors, whereas they were scarce during the earlier period. It appears that there are currently more than 100 hyperprolific authors per year.
Numerous authors, particularly in the field of medical sciences, demonstrated a lower co-authorship-adjusted Schreiber Hm index compared to the Hirsch H index. The H index measures the number of papers (H) that have been cited at least H times by others. Similarly, the Schreiber Hm index is calculated based on this concept, but each paper is assigned a fractional value of 1/k, where k represents the number of authors involved. This modification was introduced by Schreiber in a paper titled "A modification of the h-index: The hm-index accounts for multi-authored manuscripts" published in the Journal of Informetrics in 2008.
In the medical and life sciences, the H index tends to be approximately 2.5 times higher than the Hm index on average for a typical scientist, whereas in other sciences (excluding Physics), the H index is roughly twice as high as the Hm index. The chart below depicts the relationship between the Hirsch H index (horizontal axis) and the Schreiber Hm index (vertical axis) for a group of 265 hyperprolific authors. The authors are differentiated based on whether they belong to the medical/life sciences or other sciences (excluding Physics).
