R E S E A R C H A R T I C L E Open Access
‘Predatory’open access: a longitudinal study
of article volumes and market characteristics
and Bo-Christer Björk
Background: A negative consequence of the rapid growth of scholarly open access publishing funded by article
processing charges is the emergence of publishers and journals with highly questionable marketing and peer
review practices. These so-called predatory publishers are causing unfounded negative publicity for open access
publishing in general. Reports about this branch of e-business have so far mainly concentrated on exposing lacking
peer review and scandals involving publishers and journals. There is a lack of comprehensive studies about several
aspects of this phenomenon, including extent and regional distribution.
Methods: After an initial scan of all predatory publishers and journals included in the so-called Beall’s list, a sample
of 613 journals was constructed using a stratified sampling method from the total of over 11,000 journals identified.
Information about the subject field, country of publisher, article processing charge and article volumes published
between 2010 and 2014 were manually collected from the journal websites. For a subset of journals, individual
articles were sampled in order to study the country affiliation of authors and the publication delays.
Results: Over the studied period, predatory journals have rapidly increased their publication volumes from 53,000
in 2010 to an estimated 420,000 articles in 2014, published by around 8,000 active journals. Early on, publishers with
more than 100 journals dominated the market, but since 2012 publishers in the 10–99 journal size category have
captured the largest market share. The regional distribution of both the publisher’s country and authorship is highly
skewed, in particular Asia and Africa contributed three quarters of authors. Authors paid an average article processing
charge of 178 USD per article for articles typically published within 2 to 3 months of submission.
Conclusions: Despite a total number of journals and publishing volumes comparable to respectable (indexed by
the Directory of Open Access Journals) open access journals, the problem of predatory open access seems highly
contained to just a few countries, where the academic evaluation practices strongly favor international publication, but
without further quality checks.
Keywords: Open access, Scientific publishing
The publishing of scholarly journals has, like so many
other areas in business and society, undergone a radical
transformation due to the emergence of the Internet.
Mainstream publishers of subscription journals started
publishing parallel electronic versions of their journals
around the millennium shift  and today electronic de-
livery of big bundles of journals via e-licensing is the
dominating business model.
A side-effect of this transformation was the prospect it
offered for a more radical rethinking of revenue models.
New innovative publishers repositioned themselves as
service providers to the authors, publishing with them,
rather than seeing themselves as content providers to
readers. In this model, authors pay the publishers for
their services, including that the articles become freely
accessible to anybody with Internet access (open access,
OA). Other than that, the peer review practices, layout,
indexing, and so on, remain largely the same. A major
difference is nevertheless that the journals are published
only in electronic format and that the delay from
* Correspondence: email@example.com
Information Systems Science, Hanken School of Economics, PO Box
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Shen and Björk BMC Medicine (2015) 13:230
submission to publishing is usually shorter compared to
traditional scholarly journals.
Open access scholarly publishing also includes OA
journals without publishing fees and subscription journals,
which also make their electronic version freely available
directly or after a delay . In addition, the vast majority
of subscription journals from leading publishers nowadays
make individual articles available after payment, so-called
hybrid OA . Direct OA publishing is often called ‘gold’
OA. In addition, there is a ‘green’route in which authors
or third parties can legally make manuscript versions of
articles published in traditional journals freely available on
the Internet . This can be done on the authors’own
webpages, or preferably in institutional or subject-based
The number of OA journals charging authors (using
article processing charges, APCs) and the number of ar-
ticles published by them has rapidly risen in the last dec-
ade, and some journals have reached a high scientific
status in their field. Publishers have also started experi-
menting with novel forms of peer review, in particular in
so-called ‘megajournals’, which only check for scientific
rigor and validity, not for the significance of the results,
which is left to the readers to decide . The spectacular
success of the leading megajournal, PLOS ONE, which
publishes around 30,000 articles per year, shows that au-
thors appreciate this model.
This study is, however, concerned with a peculiar sub-
class of OA journals using APCs, made possible by the
global reach and cost-effectiveness of the Internet. Pub-
lishers of this type of journal seem to be in the scholarly
publishing business only in order to collect APCs and
provide rapid publishing without proper peer review for
authors who need publications in their CVs. The informa-
tion on the Internet about the journals is often strongly
misleading, and the publishers spam academics all over
the globe with requests for submissions and reviews and
for joining editorial boards.
Jeffrey Beall coined the phrase ‘predatory publishers’
to describe publishers of this sort of journal . Another
term that has been suggested is pseudo-journals . Beall
has also defined a long list of criteria for identifying such
journals and produces a continuously updated index of
publishers as well as individual journals fulfilling such
Predatory publishers have caused a lot of negative
publicity for OA journals using APCs, partly due to the
spam email that they constantly send out to researchers
and partly due to a number of scandals involving
intentionally faulty manuscripts that have passed their
quality control. Predatory OA is regularly discussed and
warnings are issued in academic journals, in particular
in editorials of scholarly journals  and journals widely
read by medical practitioners . This indirectly makes it
more difficult for serious OA journals to attract good
manuscripts and get accepted to indexes such as Web of
Since most of the reporting in the media about preda-
tory OA has been concerned with individual cases and
there have been very few scientific studies of the topic,
the overall aim of this study was to: estimate the overall
size of predatory publishing; examine how it has grown
in the last few years; and measure key characteristics of
Reports of substandard or even nonsensical papers having
been published in peer-reviewed journals have gained a lot
of publicity through coverage in the popular press. In
2009, Phil Davis reported that he and a colleague had
submitted a grammatically correct but nonsensical manu-
script generated by a software program to Bentham’sOpen
Information Science Journal, and that he had subsequently
received a mail stating that the article had been accepted
for publishing, provided he would first pay the publication
charge of 800 USD . An experiment designed by the
journalist John Bohannon, in which a spoof manuscript
containing major methodological errors and other weak-
nesses was accepted by 157 journals and rejected only by
98, also caught the attention of the general media .
The problem with these types of studies is that they tell
little about the scientific quality of the average papers in
these journals. They do demonstrate that the peer review
practices are often so deficient that just about any sort of
paper could be accepted for publishing without revisions
in many of these journals.
A few case studies of predatory journals have been
reported. Djuric describes in detail the publishing pres-
sures in Serbia, where the government requires publishing
in journals having an ISI impact factor for academic ap-
pointments and even to obtain a PhD . This has led to
a niche market for some local publishers, which have
managed to get their journals into Web of Science, in the
wake of Thomson Reuter’s drive to index more regional
journals during the latter half of the previous decade.
Djuric sent a purposefully flawed manuscript to one such
journal, in which several of his university colleagues had
published recently, and got an acceptance the next day
with instruction on how to pay the APC.
Lukićet al. discuss a number of cases of ‘hijacked’
journals. In such cases, the activities are directly fraudu-
lent . The hijackers create websites with the same
names as respectable journals and then solicit manuscripts
via spam email.
A particularly interesting but somewhat atypical case
is offered by Experimental & Clinical Cardiology .
The journal had for 17 years been published by a respect-
able Canadian subscription publisher. The journal, which
Shen and Björk BMC Medicine (2015) 13:230 Page 2 of 15
had a JCR impact factor (0.7), was purchased by investors
of obscure background, changed the business model to
OA, funded by an APC of 1,200 USD, and rapidly in-
creased the number of articles from 63 in 2013 to over
1,000 in 2014.
The only published empirical qualitative study that we
could find which sheds light on the dilemma of preda-
tory publishing is the study by Omobowale et al. 
who interviewed 30 academics from two Nigerian univer-
sities. A central finding was the difficulty of getting
published in ‘Western’journals, while at the same time,
university administrations requiring ‘international’pub-
lication; two factors that together have been strong drivers
for the emergence of the market demand for ‘predatory’
There have been a couple of published studies about
the volume and other characteristics of predatory journals.
Xia examined 297 journals listed in Beall’slistofstanda-
lone predatory journals, and found an average APC of 94
USD and a range of yearly articles of between 4 and 2,286
(mean 227 articles, median 86) .
Xia et al. also studied the origin of authors in seven
pharmacological journals included in the above list and
found a strong dominance of Indian authors, with Niger-
ian and Pakistani authors in second and third place .
Ezinwa Nwagwu and Ojemeni studied 34 journals pub-
lished by Nigerian-based publishers, Academic Journals
Inc. and International Research Journals, both focusing
in biomedicine . They found that 57 % of authors were
from Asia and 28 % from Africa, with Nigeria, China and
India being the leading countries.
The specific research questions of this study were:
What is the current number of predatory journals
(both active and empty)?
What number of articles are published in them per
year and how have these numbers evolved over the
past few years?
What is the distribution of articles over broad
In what countries are they published?
From what countries do the authors come?
How much do they charge the authors for publishing?
How rapidly do these journals publish?
Identifying predatory publishers
The first question to be asked is how to define a preda-
tory publisher (as well as journal). For practical purposes
it would have been impossible for us to construct a new
or adapted list of criteria and then search the Internet
for publishers and/or journals fulfilling these criteria.
Instead, the work already done by Beall in compiling his
index of predatory publishers as well as individual preda-
tory journals was used as the starting point for empirical
data collection. Beall has defined a detailed list of criteria
 for determining if a publisher/journal is predatory.
The list is rather long with 48 criteria, for either the
publisher or individual journal, and is grouped under
four major headings (editor and staff, business manage-
ment, integrity and other). The criteria cover a vast array
of direct and indirect indicators of the lack of a rigorous
scientific quality control of the published articles as well
as of the publishers trying to establish a reputable image
in order to attract submissions. For instance, it is often
very difficult to find out in which country the publisher
operates in practice. At the same time, authors and insti-
tutions are often assumed to base their evaluation of
journals at least in part based on the publisher’s location,
with a preference for US and Western European locations.
Another indicator is that some publishers have rapidly
created vast portfolios of journals covering just about all
fields of science, many of which lack content. A third is
that many publishers advertise very rapid turnaround
times from submission to publication, which would defeat
the purpose of peer review by competent researchers.
Both of the lists (which are regularly revised) were
downloaded on 1 September 2014 . At that time, the
list of publishers included 614 items and the list of indi-
vidual journals had 416 items. The publishers of the lat-
ter were classified as single-journal publishers in our
study, leading to a total number of 1,030 publishers as a
starting point. The next step was to review each pub-
lisher’s website in order to count the number of journals
published and to record the publisher’s country of ori-
gin. We excluded 64 publishers from the entire popula-
tion for the reason that they had invalid links, published
no journals or provided no journal-related information.
Of the remaining 966 publishers, we found a total of
11,873 published journals. This preliminary analysis dem-
onstrated the heterogeneity of predatory publishers in
terms of their journal size; most publishers are relatively
small with less than ten journals, but there are several
publishers with large fleets of journals.
It would have taken a lot of effort to manually collect
publication volumes and other data for all 11,873 jour-
nals, so the only practical solution was to make a sample
of journals to generalize from. One option would have
been a fully random sample, with each journal having
the same chance of being selected. We suspected, how-
ever, that journals from small publishers often publish a
much higher number of articles than those of large pub-
lishers, and this was verified in a small pilot test, using
data from ten random journals from small and large
Shen and Björk BMC Medicine (2015) 13:230 Page 3 of 15
publishers, respectively. Hence, a fully random sample
would probably have resulted in an underestimation of
the total number of articles, since journals from the large
publishers with large journal portfolios would have domi-
nated the picture and very few journals from single-
journal publishers would have been included in the sample.
Instead we chose a stratified multistage sampling based on
the size of the publishers by first splitting the publishers
into four size strata (100+ journals, 10–99 journals, 2–9
journals and single-journal) and then randomly sam-
pling publishers within each of these strata. The sampling
process is illustrated in Fig. 1.
In the first stage of sampling, we randomly selected a
total of 290 publishers from the different strata. In the
case of the 100+ stratum, we did not in fact sample but
included all 20 publishers in that category. After that, a
Fig. 1 Sampling process
Shen and Björk BMC Medicine (2015) 13:230 Page 4 of 15
random number of journals were chosen among the in-
cluded publishers. In the 100+ stratum, ten journals
were sampled per publisher. Both in the 10–99 and 2–9
strata, we sampled two journals from each publisher. In
the single-journal strata, considering that such journals
are more likely to produce more articles, more journals
(n = 127) than in the other strata were fully sampled so
that more reliable results concerning the total article
volumes from this stratum could be obtained. This re-
sulted in a total sample of 613 journals.
Due to the use of multistage stratified sampling design,
the sampling weight W
attached to each journal is equal
to the reciprocal of its overall probability of selection,
which is the product of the probability of selecting the
publisher at the first stage (P
) and the probability of
selecting the j
journal from the selected i
at the second stage PjiðÞ
the analysis was calculated according to the following
The following data were extracted for each sampled
journal: registered in the Directory of Open Access Jour-
nals (DOAJ) or not; ISSN number; subject field of the
journal; article volumes in 2010–2014; and APC.
The results obtained from searching journals’titles
from Beall’s list, on the DOAJ website (doaj.org) were
collected in order to estimate the proportion of current
predatory journals included in the DOAJ. The discipline
breakdown is based on a previous study . In addition,
we decided to introduce a new category called ‘general’to
represent the subject areas of journals that encompass
more than one classified discipline. Finding out the APC
was mostly straightforward, but some journals had very
flexible charges depending on different factors, for in-
stance, the number of authors, their countries (for ex-
ample low-income, middle-income and high-income
countries), identities (for example students, researchers,
and so on), and the length and type of articles (for ex-
ample review articles, research articles, and so on). To
journals, we studied ten articles from the journal, estimated
the likely cost and then calculated the average using a
method replicated from an earlier study . All the APCs
were counted based on the prices listed at the time of data
collection. The currency used was the US Dollar (USD)
and the prices given in currencies other than the USD were
converted according to the exchange rate on Currency
We also wanted to estimate the average publishing
speed (submission to publication) of predatory journals
as well as the geographical spread of authors. For this
purpose we collected five random articles for such jour-
nals where the submission and publication date is avail-
able in the articles themselves. Since some journals have
fewer than five articles in all, this resulted in a sample of
205 articles obtained from 47 journals. For the calcula-
tions of speed of publication we produced both means
and medians, since we noticed a few outlier articles with
very long delays.
The analysis in this study focused on descriptive statis-
tics using Excel. The collected sample data were used to
estimate the total number of active journals and the total
predatory OA publication volumes between 2010 and
2014 across different strata and overall as well as the an-
nual average number of articles published per journal.
In view of the use of stratified multistage sampling, the
following formula was applied to calculate the population
γst is the estimated population total, Lis the
number of strata, n
is the total sample size of stratum i,
is the sample weight for the j
observation in the
is the value of unit jin stratum iand ^
the estimated population mean.
Since journals for all 20 publishers in the 100+ strata
were sampled and the total number of journals per pub-
lisher were known, we calculated the total article volume
for the stratum by multiplying the average number of ar-
ticles per journal for each publisher with that publisher’s
number of journals, and then summing up the results
over the 20 publishers.
Regarding the statistical reliability of our results, we
calculated the standard error for key mean estimates for
the 95 % confidence level. Since we did not use fully ran-
dom samples, it was not possible to obtain the exact
standard error of means; however, what we could do was
to provide approximate standard errors for a few results.
The standard error is defined as an estimate of the stand-
ard deviation of a sampling distribution. We could com-
pute standard error (SE) under the total population size
N, the population size N
in stratum i, the sample size n
in stratum i, the sample estimate of the population stand-
ard deviation s
in stratum iby the following formula :
Shen and Björk BMC Medicine (2015) 13:230 Page 5 of 15
In order to identify whether the average APC and pub-
lishing speed of the four publisher strata were actually
different from each other, we calculated the Pvalue under
a statistically significant t-test at the 5 % significance level.
If the attained Pvalue was larger than 5 % then there was
no significant difference between the two groups, and vice
Due to the complexity of our sampling method, our re-
sults should be treated only as rough estimates showing
the overall magnitude of predatory publishing and its
central aspects. However, we still believe that our choice
of method does not significantly affect the interpretation
of the results. The diversified results we obtained for dif-
ferent strata seem to warrant our choice.
In the reporting below we provide both the results within
each stratum and the results generalized to the whole
population, where the stratum sizes in terms of journals
have been taken into account. Particularly for estimating
the average number of articles per journal and APC level,
we excluded empty journal websites from the calculations.
Number of journals
We found 11,873 journals, published by 996 publishers
(of which 447 publish just one journal). Of these journals,
we estimate that around 67 % (around 8,000 journals)
were active, in the sense that they published at least one
article. The share of empty journal websites was particu-
larly noticeable among the journals from publishers with
journal portfolios of 100 or more journals (46 %) and
much lower in the smaller publisher strata (10–99, 23 %;
2–9, 18 %; and single, 2 %). The problem of empty place-
holder journals is a problem specific to predatory journals.
Figure 2 provides the overall development of journal
volumes over time and for the different strata. The total
number of active journals has grown rapidly from an es-
timated 1,800 journals in 2010 to around 8,000 journals
in 2014. Growth has been particularly strong in the
In total these journals published an estimated 420,000
articles in 2014, after a relatively linear growth from
53,000 in 2010 (Fig. 3). The large publishers dominated
the market in 2010 and still in 2011, but after that their
absolute article numbers only increased slightly. In 2012,
journals from the 10–99 stratum rapidly took over
market domination and have consolidated that position
even when the two smallest strata also showed continuous
Distribution over scientific disciplines
Figure 4 presents article volumes published in 2014 by
journals from different scientific disciplines. The article
volumes in journals categorized as ‘general’were largest
with an estimated 162,000 articles. A more detailed ana-
lysis would require classifying articles in ‘general’journals
into some of the other subcategories, which was beyond
the resource limitations of this study. Quite noticeable
from the figure is the large share of articles in engineering
journals (97,000 articles), followed by biomedicine with
around 70,000 articles.
Average number of articles per journal
Figure 5 shows the development of the average number
of articles per year. The overall averages grew from 30
articles per journal in 2010 to 53 articles in 2012, but
after that the number seems to have stabilized. The overall
average in each stratum conceals the fact that the average
is much higher for single-journal and 2–9publishersthan
for the two uppermost strata.
Country of publishers
Figure 6 describes the distribution of the publishers across
geographic regions. The distribution is highly skewed,
with 27 % publishing in India. A total of 52 publishers
quote addresses in several countries, for instance, often
a combination of the USA or a Western European country
with a country from Africa or Asia. In order to establish
how credible a USA/European address was, we took a
closer look at the 3D street view of the address using
Google Maps. If the result was a location that was not
credible or, for instance, a PO Box, we classified the journal
according to the alternative address. For some addresses
that were very difficult to identify, we put them in the
category of ‘impossible to determine’.
Figure 7 provides information about how publishers
are distributed in each stratum. India dominates the
single-journal publisher stratum where the share is 42 %.
Country of authors
Figure 8 describes the regional distribution of the 262
sampled corresponding authors, which is highly skewed
to Asia and Africa. Around 35 % of authors are from
India, followed by Nigerian authors (8 %) and US authors
There are clear differences in the APCs of the large and
small publishers (P<0.05), as is shown in Table 1, with
the large publishers operating more expensive journals.
Shen and Björk BMC Medicine (2015) 13:230 Page 6 of 15
We calculated the results in two ways. Firstly, by just a
direct average (each journal having equal weight). Sec-
ondly, by assigning each journal a weight according to
the number of articles published in the past five years.
The latter calculation better reflects the average APCs
paid by authors publishing in these journals. The results
turn out quite different depending on the calculation
method, in particular for the 10–99 stratum, where the
average declines from 239 USD per journal to only 104
USD per article. Also generalized to all predatory articles,
the overall average APC is only about half as high (178
USD) per article as the average calculated over journals,
indicating a clear author preference for lower priced
journals, leading to higher publication volumes. The
distribution of APCs as a function of the article volumes
in the scattergram (Fig. 9) also illustrates this pattern.
In the scatterplot of the sampled journals, there are
four outlier journals (indicated by numbers), which break
the clear pattern of diminishing article volumes as a func-
tion of increasing APCs. Journal 1, 3 and 4 are published
by large publishers (100+), and in particular journal 4
(Remote Sensing), which sticks out the most, has a JCR
impact factor of 2.6. Journal 2 is the ‘hijacked’journal
Experimental & Clinical Cardiology, which in 2014 still
retained its impact factor.
The average and median publication time for journals
and articles published in 2014 (the two measures were
calculated in the same way as for APCs) were calculated.
The results show that predatory publishers take an aver-
age of 3.6 months to publish if we calculated over journals
Fig. 2 The development of active predatory open access journals from 2010 to 2014
Shen and Björk BMC Medicine (2015) 13:230 Page 7 of 15
Fig. 4 The distribution of predatory open access articles in 2014 by scientific discipline
Fig. 3 The development of predatory open access article volumes from 2010 to 2014
Shen and Björk BMC Medicine (2015) 13:230 Page 8 of 15
Fig. 6 The distribution of publishers (n = 656) by geographic regions
Fig. 5 The development of the average number of articles per journal and year from 2010 to 2014
Shen and Björk BMC Medicine (2015) 13:230 Page 9 of 15
Fig. 7 The distribution of publishers by country for the different strata
Fig. 8 The distribution of the corresponding authors by geographic regions
Shen and Björk BMC Medicine (2015) 13:230 Page 10 of 15
and 3.3 months weighted by number of articles in 2014.
However, we consider the median (2.7 overall) a more
meaningful metric, since that eliminates the effects of a
few outlier articles with very long delays.
Standard errors and t-tests of the results
The standard errors for some of the key results are
presented in Table 2. Likewise the t-tests for some of
the stratified data are included in Table 3. Based on the
t-tests, we did not find a significant difference among the
four publisher strata in terms of their publishing speed
(P>0.05), so it was not meaningful to report the strati-
fied results but we reported only the total numbers.
Our use of Beall’s list of predatory publishers as the
main external data source can be questioned, since the
list is highly controversial. Our choice of using it as a
starting point for data collection was dictated by practical
resource constraints. Nevertheless, the process of search-
ing the websites demonstrated tangibly to us that the
publishers and sampled journals usually fulfilled several
of Beall’s criteria, although we did not systematically
record our impressions. The multi-tier sampling method
used was the most realistic option to keep the time used
for manually searching for data reasonable, and also to
enable us to study the variations between different pub-
lisher strata, which proved to be considerable.
Our estimate of the number of predatory journals is
comparable to the 10,606 journals currently (7 June 2015)
included in the DOAJ. The overlap is relatively minor. We
estimate that 7.8 % of journals from Beall’slistareindexed
in the DOAJ (the index recently tightened its inclusion
Table 1 Average APC for journals and articles published from
2010 to 2014
Publisher stratum Average APC for
journals in USD
Average APC for articles published
(2010–2014) in USD
100+ journals 605 796
10–99 journals 239 104
2–9 journals 215 133
Single-journal 98 83
Total 304 178
Fig. 9 Scatter plot of article numbers versus article processing fee
Shen and Björk BMC Medicine (2015) 13:230 Page 11 of 15
criteria). The overall volume of articles published in
predatory journals is also of the same magnitude as in
the journals indexed in DOAJ. Laakso and Björk 
estimated that number to be 340,000 in 2011, and ex-
trapolating the growth would have meant roughly half a
million in 2014. For comparison, the number of articles
published in ISI-indexed journals was estimated to be
1,033,000 in 2009 .
Until 2012, the growth in predatory article numbers oc-
curred mainly through publishers who set up large (100+)
journal portfolios, and who on average charge almost 800
USD, but during the past three years the 10–99 journal
Table 2 The standard error for article volumes in 2014, average number of articles per journal, average APC for journals and articles,
and average and median publication time for journals and articles
Statistics summary Estimated value Standard error (a = 95 %)
Total article volumes published in 2014 419,273 90,954
Average number of articles per journal 2010 30 5
2011 42 9
2012 53 13
2013 49 9
2014 53 8
Average APC for journals in USD 100+ journal publisher 605 41
10–99 journal publisher 239 26
2–9 journal publisher 215 24
Single-journal publisher 98 16
Overall 304 20
Average APC for articles published (2010–2014) in USD 100+ journal publisher 796 44
10–99 journal publisher 104 15
2–9 journal publisher 133 14
Single-journal publisher 83 17
Overall 178 17
Average publication time for journals in months 100+ journal publisher 4.4 0.9
10–99 journal publisher 2.2 0.4
2–9 journal publisher 3.4 0.8
Single-journal publisher 3.9 0.7
Overall 3.6 0.4
Average publication time for articles published (2014) in months 100+ journal publisher 2.9 0.3
10–99 journal publisher 2.2 0.3
2–9 journal publisher 4.2 0.7
Single-journal publisher 4.6 0.9
Overall 3.3 0.2
Median publication time for journals in months 100+ journal publisher 2.6 (2.1, 4.5)
10–99 journal publisher 2.1 (1.0, 3.0)
2–9 journal publisher 3.7 (1.8, 4.7)
Single-journal publisher 3.2 (2.6, 5.2)
Overall 2.7 (2.0, 4.2)
Median publication time for articles published (2014) in months 100+ journal publisher 2.4 (1.5, 4.3)
10–99 journal publisher 1.9 (1.1, 3.3)
2–9 journal publisher 4.2 (2.6, 5.2)
Single-journal publisher 3.4 (1.8, 5.1)
Overall 2.7 (1.5, 4.5)
Shen and Björk BMC Medicine (2015) 13:230 Page 12 of 15
publishers, who on average charge only 104 USD, have
started to dominate the market.
The average number of articles per year in predatory
journals (around 50) is comparable to publishing volumes
in DOAJ-indexed OA journals, where the average yearly
number of articles has slowly risen and was 40 articles
per journal in 2009 . Due to the emergence of mega-
journals, the average is likely to be higher today. Björk
et al. estimated the average number in ISI-indexed
journals (mostly subscription) to be 111 in 2007 .
Growth in article numbers within predatory journals
has in the past two years mainly occurred in the two
lowest strata, which tend to have much higher annual
publication volumes. Indian journals have a strong
position especially in the single-journal stratum.
Our data showed a big difference in APC levels depend-
ing on the stratum. The APCs by predators are, neverthe-
less, much lower than the APCs by more credible OA
publishers, which on the other hand often offer waivers
from the charges to authors from developing countries.
The average of DOAJ journals with APCs is around
900–1,000 USD [26, 27]. Currently leading universities
in the UK and Germany, which fund APCs centrally,
tend to pay on average 1,200–1,300 USD .
Using our data for the number of articles and average
APC for 2014, our estimate for the size of the market is
74 million USD. The corresponding figure for OA jour-
nals from reputable journals has been estimated at 244
million USD in 2013 . The global subscription market
for scholarly journals is estimated to be around 10.5
billion USD .
A study by Solomon and Björk  about the sources
of funding for the APCs showed that in the case of au-
thors from countries with a GDP per capita of over
25,000 USD, only 10 % of the APCs came from personal
funds, whereas the proportion for authors from develop-
ing countries (under 25,000) was 39 %. That study con-
cerned DOAJ-indexed OA journals of relatively good
reputation, a third of which with JCR impact factors. If au-
thors from low-income countries to a large extent need to
pay the APC out of their own pockets, then this explains
the generally low average of 178 USD and the fact that
predatory journals with lower prices tend to have grown
much faster recently.
Our results concerning the regional distribution of
authorship can be compared with the results of Xia et al.
 who studied the authorship distribution for seven
pharmaceutical predatory journals, and Ezinwa Nwagwu
and Ojemeni  who studied 34 journals from two
Nigerian-based predatory publishers. The minor differences
journal samples in the above studies, for instance, the
Table 3 T-tests for average APC and publication time for journals and articles
100+ journal publisher 10–99 journal publisher 2–9 journal publisher Single-journal publisher
Average APC for journals
100+ journal publisher - P<0.05 P<0.05 P<0.05
10–99 journal publisher - - P>0.05 P<0.05
2–9 journal publisher - - - P<0.05
Single-journal publisher - - - -
Average APC for articles published in 2010–2014
100+ journal publisher - P<0.05 P<0.05 P<0.05
10–99 journal publisher - - P>0.05 P>0.05
2–9 journal publisher - - - P<0.05
Single-journal publisher - - - -
Average publication time for journals
100+ journal publisher - P>0.05 P>0.05 P>0.05
10–99 journal publisher - - P>0.05 P<0.05
2–9 journal publisher - - - P>0.05
Single-journal publisher - - - -
Average publication time for articles published
100+ journal publisher - P>0.05 P>0.05 P<0.05
10–99 journal publisher - - P<0.05 P<0.05
2–9 journal publisher - - - P>0.05
Single-journal publisher - - - -
Shen and Björk BMC Medicine (2015) 13:230 Page 13 of 15
journals studied by Ezinwa Nwagwu and Ojemeni 
had an average APC of 636 USD, which could explain
the lower share of Indian authors.
An interesting finding is the very low share of South
America, both among publishers (0.5 %) and correspond-
ing authors (2.2 %). It would no doubt be an interesting
question to study the reasons for this, which could be a
combination of factors, where the infrastructure in Latin
America differs from countries like India and Nigeria.
Above we have reported the estimated geographical
spread of predatory article authorship in terms of abso-
lute numbers per year of articles, which is highly skewed
with India at the top. A slightly different viewpoint would
be a per capita calculation, which takes into account the
relative sizes of countries or economies. In our view a par-
ticularly interesting comparison is one in which the size of
predatory publication is compared to the production of
high quality article from the same country. We used fig-
ures from the Web of Science (InCites regions report)
about authorship for the years 2013–2014 to calculate the
ratio of predatory to Web of Science-indexed articles. For
the four biggest contributors of predatory articles, the
USA had a low ratio of 6 %, Iran 70 %, India 277 % and
Nigeria a staggering 1,580 %.
The publishing delays we found were much shorter than
for scholarly journals in general. Björk and Solomon 
found delays of 9–18 months, depending on the field of
science, with social sciences having the longest delays. The
average delay for the OA journals in that study was 5.9
months, thus clearly shorter than for subscription journals
but longer than for predatory journals. The range of
average delays for OA megajournals was 3–5months.
Unlike many writings about the phenomenon, we be-
lieve that most authors are not necessarily tricked into
publishing in predatory journals; they probably submit
to them well aware of the circumstances and take a cal-
culated risk that experts who evaluate their publication
lists will not bother to check the journal credentials in
detail. Hence we do not uncritically see the authors as
unknowing victims. The universities or funding agencies
in a number of countries that strongly emphasize publish-
ing in ‘international’journals for evaluating researchers,
but without monitoring the quality of the journals in
question [16, 33], are partly responsible for the rise of this
type of publishing. The phenomenon should probably,
however, be seen more broadly as a global North-South
dilemma where institutions in developing countries are
unable to break free from the increasingly globalized
and homogenized view of academic excellence based on
‘where’and how often one publishes, instead of ‘what’
is published and whether the results are relevant to local
needs. In that sense, these authors and their institutions
are part of a structurally unjust global system that ex-
cludes them from publishing in ‘high quality’journals on
the one hand and confines them to publish in dubious
journals on the other.
Leading respectable OA publishers have not stood by
silently as OA has been given a bad name by predators.
Rather than blacklisting journals, which Jeffrey Beall is
doing, the strategy has been one of defining quality cri-
teria and accreditations of journals that meet those .
For instance, the DOAJ has, since 2014, imposed stricter
criteria for inclusion and has filtered out journals that
do not meet them . Membership in the Open Access
Scholarly Publishers Association (OASPA) is also contin-
gent on meeting quality criteria. An increasing share of
respectable OA journals is also nowadays indexed by the
We are not particularly satisfied with the term ‘preda-
tory’, since we believe that the term has a highly negative
connotation and we feel it is slightly misleading. We
would instead have preferred to talk of ‘open access jour-
nals with questionable marketing and peer review prac-
tices’. Nevertheless the term ‘predatory’open access is by
now so established for this phenomenon that in the end
we decided to use it. A practical consideration is that an
article using the term in the title or frequently in the text
is more likely to be picked by readers searching the inter-
net for more information about this phenomenon.
In this study, we used a multistage stratified sampling
method to take a look into the predatory publishers and
journals on Beall’s list and generated their development
trend over time. We found that the problems caused
by predatory journals are rather limited and regional, and
believe that the publishing volumes in such journals will
cease growing in the near future. Open access publishing
is rapidly gaining momentum, in particular through the
actions of major research funders and policy makers. This
should create better opportunities for researchers from
countries where predatory publishing is currently popular,
to get published in journals of higher quality, in particular
since most journals have a policy to waive the APCs for
authors from developing countries.
APC: Article processing charge; DOAJ: Directory of Open Access Journals;
ISI: Institute for Scientific Information; ISSN: International Standard Serial
Number; JCR: Journal Citation Reports; OA: Open access; OASPA: Open
Access Scholarly Publishers Association; SE: Standard error.
The authors declare that they have no competing interests.
The study was planned by CS and B-CB and in cooperation, and CS collected
and analyzed the empirical data. Both authors contributed to the reporting.
Both authors read and approved the final manuscript.
Shen and Björk BMC Medicine (2015) 13:230 Page 14 of 15
CS is a doctoral student in Information Systems Science at the Hanken School
of Economics, Helsinki, Finland. B-CB is professor of Information Systems Science
at the Hanken School of Economics, Helsinki, Finland.
We acknowledge Cecilia Grönroos who helped with the initial data collection.
Also several colleagues have commented on the draft manuscript, in particular
Paul Catani provided guidance concerning the statistical analysis. In addition,
the excellent point of view provided by the reviewer’sreportofLeslieChanfor
our discussion is appreciated.
Received: 30 April 2015 Accepted: 1 September 2015
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