The FASEB Journal • Life Sciences Forum
Comparison of SCImago journal rank indicator with
journal impact factor
Matthew E. Falagas,*,†,‡,1 Vasilios D. Kouranos,* Ricardo Arencibia-Jorge,§ and
Drosos E. Karageorgopoulos*
*Alfa Institute of Biomedical Sciences (AIBS), Athens, Greece; †Department of Medicine, Tufts
University School of Medicine, Boston, Massachusetts, USA; ‡Department of Medicine, Henry
Dunant Hospital, Athens, Greece; and §Network of Scientometrics Studies for Higher Education,
National Scientific Research Center, Havana, Cuba
The application of currently available
sophisticated algorithms of citation analysis allows
for the incorporation of the “quality” of citations in
the evaluation of scientific journals. We sought to
compare the newly introduced SCImago journal rank
(SJR) indicator with the journal impact factor (IF).
We retrieved relevant information from the official
Web sites hosting the above indices and their source
databases. The SJR indicator is an open-access resource, while the journal IF requires paid subscription. The SJR indicator (based on Scopus data) lists
considerably more journal titles published in a wider
variety of countries and languages, than the journal
IF (based on Web of Science data). Both indices
divide citations to a journal by articles of the journal,
during a specific time period. However, contrary to
the journal IF, the SJR indicator attributes different
weight to citations depending on the “prestige” of
the citing journal without the influence of journal
self-citations; prestige is estimated with the application of the PageRank algorithm in the network of
journals. In addition, the SJR indicator includes the
total number of documents of a journal in the
denominator of the relevant calculation, whereas the
journal IF includes only “citable” articles (mainly
original articles and reviews). A 3-yr period is analyzed in both indices but with the use of different
approaches. Regarding the top 100 journals in the
2006 journal IF ranking order, the median absolute
change in their ranking position with the use of the
SJR indicator is 32 (1st quartile: 12; 3rd quartile: 75).
Although further validation is warranted, the novel
SJR indicator poses as a serious alternative to the
well-established journal IF, mainly due to its openaccess nature, larger source database, and assessment of the quality of citations.—Falagas, M. E.,
Kouranos, V. D., Arencibia-Jorge, R., Karageorgopoulos, D. E. Comparison of SCImago journal rank
indicator with journal impact factor. FASEB J. 22,
2623–2628 (2008)
ABSTRACT
The evaluation of the quality of research is important for various professional societies, individual scientists, scholarly institutions, and funding organizations
(1). The quality of a scientific contribution is primarily
estimated from the long-term impact that it has in
science. The latter can be inferred from the citations in
scientific articles that a contribution receives. These
principles have been applied in the evaluation of
scientific journals (2). The journal impact factor (IF),
first conceived in 1955 by Eugene Garfield, the founder
of the Institute for Scientific Information (ISI), has
been extensively used in the past decades as an index of
quality of scientific journals (3) and is based on citation
analysis (4).
Although the journal impact factor has been widely
regarded as the best instrument for the evaluation of
the quality of scientific journals, it has not been spared
from criticism(5– 8). Main points of consideration regarding methodological aspects in the calculation of
this index include the lack of assessment of the quality
of citations (9), the inclusion of self-citations (10 –12),
the poor comparability between different scientific
fields (13), and the analysis of mainly English-language
publications (14 –16).
In fact, many researchers have proposed different
approaches in the evaluation of the quality of scientific journals. The common point in most of these
approaches is the assessment of the quality of citations received by a journal (17–20). The quality of
citations can be estimated analyzing the networks of
scientific papers with sophisticated mathematical algorithms (21). The PageRank algorithm, used in the
evaluation of webpages by the popular Google search
engines, has been proposed as an appropriate model
for the evaluation of the quality of citations in
scientific journals (22, 23). In fact, a group of
researchers at the University of Washington developed a similar algorithm for the evaluation of the
1
Key Words: bibliometric analysis 䡠 quality of publications
䡠 bibliographic databases 䡠 mathematical computing 䡠 scientometrics
0892-6638/08/0022-2623 © FASEB
Correspondence: Alfa Institute of Biomedical Sciences
(AIBS), 9 Neapoleos St., 151 23 Marousi, Greece. E-mail:
m.falagas@aibs.gr
doi: 10.1096/fj.08-107938
2623
influence of scientific journals included in the
Thompson Scientific Journal Citation Reports (JCR)
dataset (24). Furthermore, another research group
from Spanish Universities developed an indicator,
named SCImago Journal Rank (SJR) indicator, for
the assessment of the quality of scientific journals,
applying the PageRank algorithm on the Scopus
database (25). In this evolving context, we sought to
identify and evaluate the main characteristics and
differences between the widely used journal IF by ISI
and the newly introduced SJR indicator.
MATERIALS AND METHODS
We searched (January 2008) in the official relevant Web sites
for information regarding the main characteristics of the
journal IF, provided by JCR through ISI Web of Science,
Thomson Scientific, and the SJR indicator, provided by the
SCImago journal and country rank Web site, and developed
by the SCImago research group. We also searched for information pertinent to the characteristics of these two indices of
quality of scientific journals in the official Web sites hosting
the databases used by each one of the indices (ISI Web of
Science and Scopus for journal IF and SJR indicator, respectively).
In addition, we listed the journals with the top 100
journal IFs and retrieved information regarding their
ranking in the SJR indicator list by matching their interna-
tional standard serial number (ISSN). We also listed the
journals with the top 100 SJR indicators and found their
ranking in the list of journal IFs. Finally, we calculated the
median value as well as the first and third quartile values of
the absolute change in ranking order of the journals in the
two top 100 lists (with the use of each one of the compared
indices vs. the other).
RESULTS
The main characteristics of the evaluation of scientific journals in JCR and in SCImago journal rank are
summarized in Table 1. The journal IF of a specific
journal for a specific calendar year is defined by the
total number of citations (references) by articles
published during the specific year in “source” journals (potentially including the respective journal) to
any article of the specific journal that was published
during the preceding 2 yr, divided by the total
number of “citable” articles published in the respective journal during the preceding 2 yr. Articles
regarded as citable are mainly original research and
review articles.
The SJR indicator of a specific journal for a threecalendar-year period is calculated through an iteration
process that computes the “prestige” gained by the
journal through the transfer of prestige from all the
TABLE 1. Main characteristics of the evaluation of scientific journals by journal citation reports and SCImago journal
and country rank.
Characteristic
Journal citation reports
Organization
Source database
Number of journals
Languages of publication of
journals
Countries of publication of
journals
Countries of research origin
Update
Main indicator of quality of
journals
Reference period
Citation window
Journals providing citations
Weight of citations
Journal self-citations
Articles considered to
receive citations
Subject classification
Access
Secondary indices, utilities
a
2624
Imago journal and country rank
Thomson Scientific
Institute for Scientific Information (ISI) Web of
Science
⬍7934a
30
SCImago research group
Scopus (Elsevier B.V.)
71
97
Not available
Weekly
Journal impact factor (IF)
229
Daily
SCImago journal rank (SJR) indicator
1 calendar year
2 preceding years
“Source” journals (“cited-only” journals
excluded)
Equal
3 calendar years
3 past years
All other journals
Included
“Citable” (research and review articles)
2 Editions (science and social sciences), 224
subject categories
Restricted (paid subscription required after 1
month free use)
Journal immediacy index, journal cited half-life,
unified impact factor, 5-yr impact factor, selfcites, graphical representations
13,208
50
Depending on the “prestige” of the citing
journal
Not included
All types
27 subject areas, 295 subject categories
Open
H Index, self-cites, country indicators,
graphical representations
6166 science journals, 1768 social science journals.
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August 2008
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FALAGAS ET AL.
other journals included in the network of journals, by
their citations during the past 3 yr to all articles of the
specific journal published in the past 3 yr, divided by
the total number of articles of the specific journal
during the 3 yr period in regard. The amount of
prestige of each journal transferred to another journal
in the network is computed by considering the percentage of citations of the former journal that are directed
to articles of the latter journal (26).
Table 2 presents the first 20 ranked journals of all
categories with each one of the compared indices
and their corresponding rank using the other index.
Of the 20 journals with the highest journal IFs, 13
retain a position in the top 20 journals with the use of
the SJR indicator, and vice versa. Regarding the top
100 journals in the 2006 journal IF ranking order,
the median absolute change in their ranking position
with the use of the SJR indicator is 32 (1st quartile:
12; 3rd quartile: 75). Conversely, regarding the top
100 journals with the current SJR indicator, the
median absolute change in their ranking position
with the use of the journal IF is 29 (1st quartile: 10.5;
3rd quartile: 65.5).
The journals with the greatest relative increase in
their ranking order in the SJR indicator compared to
the journal IF were the journals Immunity, Molecular
Cell, Annual Review of Cell and Developmental Biology,
Cell, and Current Opinion in Cell Biology. The journals
with the greatest relative stability in their ranking
order from the journal IF to the SJR classification
were Annual Review of Physiology, Annual Review of
Biophysics and Biomolecular Structure, PLoS Biology, An-
TABLE 2. Comparative rankings of the top 20 journals by journal impact factor and SCImago journal rank indicator
SCImago journal rank
indicator
Journal impact factor
Rank
Value
Journal title
Value
Rank
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
63,342
51,296
47,237
36,525
33,508
31,583
31,441
31,354
30,028
29,194
28,697
28,588
28,533
27,596
26,681
26,576
26,054
25,800
24,370
24,176
Ca-A Cancer Journal of Clinicians
New England Journal of Medicine
Annual Review of Immunology
Annual Review of Biochemistry
Reviews of Modern Physics
Nature Reviews Cancer
Physiological Reviews
Nature Reviews Molecular Cell Biology
Science
Cell
Nature Reviews Immunology
Nature Medicine
Annual Review of Neuroscience
Nature Immunology
Nature
Annual Review of Cell and Developmental Biology
Chemical Reviews
Lancet
Briefings in Bioinformatics
Nature Genetics
7,275
3,649
22,439
16,100
2,689
9,159
7,866
12,240
5,338
15,224
11,101
7,226
8,678
12,484
6,203
14,193
2,245
1,652
2,535
9,083
19
51
1
2
79
9
16
6
30
3
7
20
11
5
23
4
93
134
84
10
3
4
10
16
14
8
11
33
6
20
13
31
21
56
45
7
53
32
1
12
47,237
36,525
29,194
26,576
27,596
31,354
28,697
18,306
31,583
24,176
28,533
19,098
24,077
14,033
15,050
31,441
14,299
18,485
63,342
28,588
Annual Review of Immunology
Annual Review of Biochemistry
Cell
Annual Review of Cell and Developmental Biology
Nature Immunology
Nature Reviews Molecular Cell Biology
Nature Reviews Immunology
Immunity
Nature Reviews Cancer
Nature Genetics
Annual Review of Neuroscience
Annual Review of Genetics
Cancer Cell
Molecular Cell
Genes and Development
Physiological Reviews
Current Opinion in Cell Biology
Nature Cell Biology
Ca-A Cancer Journal of Clinicians
Nature Medicine
22,439
16,100
15,224
14,193
12,484
12,240
11,101
9,337
9,159
9,083
8,678
8,583
8,214
8,185
8,086
7,866
7,399
7,367
7,275
7,226
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
SCIMAGO JOURNAL RANK VS. JOURNAL IMPACT FACTOR
2625
nual Review of Plant Biology, and Blood. The journals
that exhibited the greatest relative decrease in their
ranking order in the SJR indicator compared to the
journal IF were Annual Review of Astronomy and Astrophysics, JAMA–Journal of the American Medical Association, Nature Physics, Advances in Catalysis, and Behavioral and Brain Sciences. It should be mentioned that
all five of the latter journals exhibited a fall of more
than 4000 positions in their ranking order with the
use of the SJR indicator compared to the journal IF.
Exploring the considerable discrepancy in the rankings of the latter five journals, we noted as potential
causes a computational error, the presence of another journal with the same title but different ISSN,
lack of source data, and a divergence between the
number of citable articles and of total articles or
documents. Furthermore, one of the top 100 journals
according to the journal IF classification (Trends in
Ecology & Evolution) was not included in the SJR
database.
DISCUSSION
The main differences between the journal IF and the
SJR indicator derive mainly from differences in the
scientific databases used as the sources of citations, as
well as from differences in the methodology of
estimation of these indices. The latter primarily
regard the weight attributed to citations, the way of
handling self-citations, the temporal window analyzed, and the type and number of the articles of a
journal considered in the denominator of calculation
of the aforementioned indices. In terms of utility, the
main novelty introduced by the SJR indicator is open
access.
Regarding the differences in the scientific databases, on which the compared indices of evaluation
of scientific journals are applied, Scopus includes a
substantially larger collection of journals, originating
from remarkably more countries and published in a
greater variety of languages (27). Thus, in this regard
it can be assumed that SJR may provide a more
comprehensive estimation of the scientific value of
journals, particularly so for those published in nonEnglish languages (16). This is why the latter category of journals receives a great percentage of the
overall incoming citations from non-English journals
(14, 15). The latter are rather underrepresented in
the Web of Science database. Furthermore, the Web
of Science takes into consideration citations originating from a subset of source journals (28), potentially
excluding some journals published in non-English
languages, a factor that may influence the evaluation
of this category of journals (14). Yet, it should be
mentioned that although Scopus includes a larger
collection of non-English journals, the latter are still
underrepresented, constituting ⬃15% of the total
number of included journals (29). Moreover, the
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August 2008
apparent advantage of Scopus in citation analysis
originating from the breadth of its database is limited
to the time period after 1996 for which citation
analysis is available (30).
Regarding the methodology of the calculation of
the two compared indices, the most significant difference lies in the fact that the SJR indicator takes
into account not only the absolute number but also
the “quality” of citations received by a journal,
whereas the journal IF considers incoming citations
only in a quantitative manner. It is plausible that the
articles of a journal have a greater impact in science
if they are cited by journals of higher scientific
quality. Such an analysis may not have been feasible
in the past, though in today’s electronic era, powerful computational systems provide the opportunity to
apply sophisticated algorithms for the evaluation of
interactions between journals in a huge network or
universe of scientific publications. However, the simple and comprehensible methodology used in the
calculation of the journal IF, despite the controversy
raised over the years for the output data (31, 32), has
been regarded as one of the most favorable attributes
of this long-used standard of reference in the field of
analysis of scientific citations.
It should be noted though that the simple methodology used in the calculation of the journal IF has
allowed editors to use various practices aiming to
increase the impact factor of their journals (5, 33,
34). The principal ones are probably the promotion
of self-citations (10 –12, 35), the predilection for
review articles (36), and the decrease in the total
number of included articles (37). Notably, the use of
the SJR indicator allows for the estimation of a
journal’s impact without the influence of self-citations, since prestige can be transferred to a journal
by all other journals but not by itself. Instead, in JCR
providing the journal IFs, self-citation analysis for
each journal can be separately performed. However,
this factor is not incorporated in the calculation of
the journal IFs. Regarding the weight of the different
types of articles in the process of calculating the two
compared indices of scientific journals, no provision
has been made for differentiating between the value
assigned to original research articles compared to
review articles in any of the indices.
One of the major shortcomings of the SJR indicator may be the fact that it divides the prestige gained
by a journal, through the citations of its articles, to
the total number of articles included, rather than to
the number of citable articles, as is used in the
calculation of the journal IF. Although the strategy
used in the calculation of the SJR indicator may be
mathematically valid, since in theory any published
article can be cited and all citations are taken into
account in the numerator of the fraction, in practice,
article types such as correspondence articles, letters
to the editor, commentaries, perspectives, news, obituaries, editorials, interviews, and tributes are unlikely
to receive a significant number of citations (3). In
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FALAGAS ET AL.
this regard, the scientific quality of journals that
contain a large number of the latter types of articles,
which may otherwise be of interest to the reader, are
expected to be appreciably underestimated with the
SJR indicator. Yet, it should be mentioned that
neither is the journal IF an optimal index of quality
of scientific journals regarding this issue, since it
does not adjust for the fact that a great number of
total citations addressed to a journal are received by
a relatively short portion of the included articles (3,
38, 39).
The effect of the differences in the time periods used
for the assessment of the two herein compared indices
of quality of scientific journals on the accuracy of the
estimates cannot be directly inferred in the context of
the present study. It should be noted though that both
of the indices refer to the past three calendar-year
periods, although through a different approach. This
temporal window may be relatively short, particularly
for journals with an appreciable interval between receipt of an article and publication (3, 40).
An indisputable advantage of journal IF over any new
index of evaluation of quality of scientific journals is
tradition. On the one hand, authors compete for
publishing the products of their research in highly
ranked journals (41). On the other hand, journal
editors elect to publish scientific articles that are expected to be highly cited (37). Thus, it can be assumed
that journal IF rankings would have influenced accordingly the quality of the journals over the years in which
they have been considered as the sole standard of
reference (3).
Although our study did not aim to systematically
assess the comparability in journal rankings between
the novel SJR indicator and the well-established
journal IF index, we observed that the introduction
of the SJR indicator does not bring about radical
changes in this regard. In fact, half of the journals in
the top 100 journal IF list are placed within a
reasonable range of 32 ranking places in the SJR
indicator journal list. Some striking inconsistencies
observed in the rankings of the new SJR indicator,
compared to the journal impact factor, should be
attributed to the “precocity” of the new indicator
rather than to systematic differences in the methodologies used. In fact, the two methodologies have
been systematically compared in previous studies. A
weighted PageRank algorithm applied in the same
dataset used for the derivation of the journal impact
factor provided results that correlated significantly
with the later index (23). However, this correlation
was moderately strong and differed between various
scientific fields, for instance, for medical journals (9,
23).
The SCImago journal rank indicator is a novel
instrument for the evaluation of scientific journals
that may challenge the established premiership of
the journal IF in ranking scientific journals. It provides unrestricted (open) access, is based on a larger
source journal database, and focuses on the quality of
SCIMAGO JOURNAL RANK VS. JOURNAL IMPACT FACTOR
citations that a journal receives by other journals,
rather than the absolute number. However, the sophisticated methodology used in the calculation of
the SJR indicator needs to be adequately validated,
and certain characteristics may need to be reconsidered before definitive conclusions for its applicability
could be drawn. It appears, though, that the election
of one index or the other would be mostly a matter of
whether the popularity or the quality of a journal is
considered as the primary criterion for the evaluation of scientific journals.
The authors have no conflicts of interest to declare. No
funding was received for this study.
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