Bibliometric indicators and core journals in physical and rehabilitation medicine.

TLDR: Comparing and comment on different bibliometric indicators related to some leading journals in rehabilitation, in order to provide further insights regarding their practical usefulness for Physical and Rehabilitation Medicine.

Abstract: Background and objective: the concept of the “standing” of scientific journals (in terms of influence, prestige, popular ity, etc.) is multi-dimensional and cannot be captured adequately by a single indicator. The aim of this report is to compare and comment on different bibliometric indicators related to some leading journals in rehabilitation, in order to provide further insights regarding their practical usefulness for Physical and Rehabilitation Medicine. Discussion: The commonly used Journal Impact Factor and the new SCImago Journal Rank indicator are measures of average “impact per paper”. Other new measures show potentially useful complementarities with them and warrant further attention. For example, the Eigenfactor score represents a measure of total “citation impact” and seems sufficiently to express the “importance” of a journal. In fact, the information conveyed by the Eigenfactor score corresponds to a general consensus of journal status in Physical and Rehabilitation Medicine, as expressed by the European Consensus Committee on “International Rehabilitation Journals” and captured by a survey among European Physical and Rehabilitation Medicine researchers.

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SPECIAL REPORT
J Rehabil Med 2011; 43: 471–476
J Rehabil Med 43
© 2011 The Authors. doi: 10.2340/16501977-0821
Journal Compilation © 2011 Foundation of Rehabilitation Information. ISSN 1650-1977
Background and objective: The concept of the “standing” of
scientic journals (in terms of inuence, prestige, popular-
ity, etc.) is multi-dimensional and cannot be captured ad-
equately by a single indicator. The aim of this report is to
compare and comment on different bibliometric indicators
related to some leading journals in rehabilitation, in order to
provide further insights regarding their practical usefulness
for Physical and Rehabilitation Medicine.
Discussion: The commonly used Journal Impact Factor and
the new SCImago Journal Rank indicator are measures of
average “impact per paper”. Other new measures show po-
tentially useful complementarities with them and warrant
further attention. For example, the Eigenfactor score rep-
resents a measure of total “citation impact” and seems suf-
ciently to express the “importance” of a journal. In fact, the
information conveyed by the Eigenfactor score corresponds
to a general consensus of journal status in Physical and Re-
habilitation Medicine, as expressed by the European Con-
sensus Committee on “International Rehabilitation Jour-
nals” and captured by a survey among European Physical
and Rehabilitation Medicine researchers.
Key words: bibliometric analysis; impact factor; Eigenfactor
Score; Physical and Rehabilitation Medicine.
J Rehabil Med 2011; 43: 471–476
Correspondence address: Franco Franchignoni, Fondazione
Salvatore Maugeri, Clinica del Lavoro e della Riabilitazione,
IRCCS, Via Revislate 13, I-28010 Veruno (NO), Italy. E-mail:
franco.franchignoni@fsm.it
Submitted January 11, 2011; accepted April 5, 2011
INTDRODUCTION
There is no one simple bibliometric indicator that can express
the “standing” (in terms of inuence, prestige, popularity, etc.)
of a scientic journal.
The Journal Impact Factor (JIF) is perhaps the best-known
bibliometric measure of scientic impact, due to its simple
and intuitive denition. It reects the frequency with which
the “average article” in a journal has been cited in a particular
period. It is produced by the Institute for Scientic Information
(ISI; currently Thomson Reuters, a US private commercial
enterprise) and is inserted in its Journal Citation Reports
(JCR), now available at the portal Web of Science (WoS). Until
recently, WoS was the only citation database for conducting
extensive citation searching and bibliometric analysis, widely
covering scholarly scientic and technical literature.
Although the JCR itself warns that the JIF should not be
relied on as the sole source of information when comparing
and evaluating publications (and particularly when compar-
ing citation counts of different disciplines), this index has
been frequently used as an exclusive proxy for the relative
importance of a journal (with journals with higher impact
factors deemed to be more important than those with lower
ones). However, many drawbacks of the JIF have been ex-
tensively discussed (1, 2), and it is clear that at present it is
a far-from-perfect measure of scientific impact (3). Among
others, it has been pointed out that the JIF counts the number
of citations received, but ignores any information about the
sources of those citations.
In the past few years several new databases or tools that
provide citation searching capabilities have been developed
(4, 5). This has created competitiveness, which is productive
for users, and some of the tools are sufficiently compre-
hensive and/or multidisciplinary in nature to pose a direct
challenge to the dominance of the WoS. In parallel, new
measures of the scientific performance of journals have been
proposed and discussed (6–8). However, at present it is not
clear which measures best express the various aspects and
interpretations of concepts such as “impact”, “influence”,
“prestige”, etc. (9).
The aim of this report is to compare and comment on dif-
ferent (and often new) bibliometric indicators related to some
leading journals in rehabilitation, in order to provide further
insights regarding their practical usefulness for Physical and
Rehabilitation Medicine (PRM).
METHODS
Selection of journals
For the analyses the rst 16 journals in the category Rehabilitation
of the JCR – Science Edition 2009 (the latest available on the web)
were taken into account. Only one journal (Supportive Care in Cancer)
was preliminarily discarded, as it was judged by expert opinion not to
belong to this category (incidentally, it is indexed in Scopus/SCImago
under the category “Oncology”). Two independent reviewers (FF,
SML) extracted data regarding the 15 remaining journals (see Table
I). Data were imported into an Excel spreadsheet for further analysis.
Any disagreement was resolved by iteration and consensus.
BIBLIOMETRIC INDICATORS AND CORE JOURNALS IN PHYSICAL AND
REHABILITATION MEDICINE
Franco Franchignoni, MD
1
and Susana Muñoz Lasa, MD
2
From the
1
Unit of Occupational Rehabilitation and Ergonomics, “Salvatore Maugeri” Foundation, Clinica del Lavoro e
della Riabilitazione, IRCCS, Rehabilitation Institute of Veruno (NO), Italy and
2
Department Medicina Fisica y
Rehabilitacion, Universidad Complutense, Madrid, Spain

472
F. Franchignoni and S. Muñoz Lasa
Bibliometric indicators
JIF and 5-Year JIF (5Y-JIF). The JIF represents “the average number of
times articles from the journal published in the past 2 years have been
cited in the JCR year” (1). For example, the 2009 JIF of journal X is
calculated by dividing the number of 2009 citations (in journals indexed
by Thomson ISI) of all articles published by journal X in 2007 and 2008
by the total number of articles deemed to be “citable” by Thomson ISI
that were published in journal X in 2007 and 2008.
Similarly, the 5Y-JIF is “the average number of times articles from
the journal published in the past 5 years have been cited in the JCR
year”.
The 2009 JIF and 5Y-JIF are reported here.
Eigenfactor Score (EFS) and Article Inuence Score (AIS). According
to the creators of the EFS, this indicator should give a measure of that
journal’s importance within the network of academic citations (7). The
EFS calculation is based on the number of times articles published in
the journal in the past 5 years have been cited in a given year, but it
also considers (using an iterative ranking scheme) which journals have
contributed these citations, so that highly-cited journals will inuence
the network more than lesser-cited journals (Fig. 1). Each contribution
is corrected for differences in citation patterns across disciplines and
journals, and journal self-citations are removed (see www.eigenfactor.
org/methods.htm). The basic idea behind the Eigenfactor metrics is that
the citations published by scholarly journals form a vast network link-
ing the collective research output. In Fig. 1, each node in the network
represents an individual journal, and each arrow represents citations
from one journal to another. The links are weighted and directed: strong
weights represent large numbers of citations, and the direction of the
arrow indicates the direction of the citations. The Thompson ISI JCR
is its reference database.
The AIS is calculated by dividing a journal’s EFS by the number of
articles published by the journal (normalized as a fraction of all articles
in all publications). As such, this index is an indicator that allows a
per-article comparison based on the Eigenfactor approach, and aims
to determine the average inuence of a journal’s articles over the rst
5 years after publication. Thus, the AIS is comparable to the 5-Y JIF,
except that the citations are weighted to reect the “inuence” of the
citing journals.
The 2009 EFS and AIS, available in the online version of the JCR,
were taken into account.
SCImago Journal Rank indicator (SJR). According to its creators,
the SJR aims to measure the current “average prestige per paper” of
journals (6). The SJR is calculated through an iteration process (similar
to that used to calculate citation PageRank and EFS), which computes
the “importance” gained by the other journals included in the network
of journals, by the citations during the past 3 years of all articles of
the specic journal published in the past 3 years, divided by the total
number of articles of the specic journal during the 3-year period in
question. The amount of “prestige” of each journal transferred to an-
other journal in the network is computed by considering the percentage
of citations of the former journal that are made in reference to articles
of the latter journal (see www.scimagojr.com/SCImagoJournalRank.
pdf) (6). The SJR is based on Scopus, at present the world’s larg-
est electronic database of abstracts and citations for peer-reviewed
literature (4, 5). Overall, the SJR is a size-independent hybrid metric
that measures the current average performance per paper of journals
(like the JIF, 5Y-JIF and AIS) using an approach based on eigenvector
centrality (such as the EFS) (10, 11). The last available SJR (2008) is
considered in this report.
The h-index. This was proposed by Hirsch in 2005 (8) to rank authors
according to their rank-ordered citation distributions, but it was
quickly extended to scientific journals (12) as a useful supplement
to evaluate their impact (see http://en.wikipedia.org/wiki/H-index).
Journals (or researchers) have an h-index of n when they have
published n papers, each of which has been cited at least n times
to date. The h-index aims to provide a single-number innovative
metric, combining the effect of quantity (number of publications)
and impact (citation rate).
Two different h-indices for journals are reported here. The rst (h-
index1) is the one produced by SJR and expresses “the journal’s number
of articles (n) that have received at least n citations” (it is a “life-time”
index, calculated taking into account the whole journal production, since
1996). The second (h-index2) is the h-index that has been produced
by WoS, limiting the timeframe to 5 years (2003–2007), in order to
mitigate the possible inuence of journal name changes and to ensure
comparability of data across journals with a different lifespan.
RESULTS
Table I reports the correlation matrix of the different indicators
(Spearman’s correlation coefcient). Some indicators show a
moderate to high degree of correlation.
Table I. Correlation coefcients (Spearman’s rho) between each pair of
journal indicators
Journal
indicator JIF 5Y-JIF EFS AIS SJR h-index1 h-index2
JIF –
5Y-JIF 0.71 –
EFS –0.37 –0.21 –
AIS 0.54 0.92 –0.36 –
SJR 0.45 0.87 0.01 0.85 –
h-index1
–0.05 –0.16 0.76 –0.34 0.09 –
h-index2
0.10 0.21 0.75 0.06 0.41 0.72 –
JIF: JCR Journal Impact Factor; 5Y-JIF: 5-year Journal Impact Factor; EFS:
Eigenfactor score; AIS: Article Inuence score; SJR: SCImago Journal
rank indicator; h-index1: h-index calculated by SCImago; h-index2:
h-index calculated by Web of Science with a 5-year window.
Fig. 1. A simplied citation network, analysed with an iterative ranking
scheme. Arrows indicate citations from each of the 4 journals (A, B, C, and
D) to one other. The method denes an iterative algorithm that computes
values of centrality until a steady-state solution is reached. The importance
(prestige) of the nodes (journals) is redistributed at each iteration in terms
of their connections with other nodes. At the end, larger circles represent
more important journals.
J Rehabil Med 43

473
Bibliometric indicators and core journals in PRM
The values and rankings of the 7 selected journal indicators
related to the 15 top journals in the JCR Rehabilitation category
are shown in Table II.
DISCUSSION
In the biomedical eld, numerous efforts have been made to
rene the mode of information retrieval and augment citation
analysis (4, 5).
First, a new research trend is clearly emerging, aimed at
developing impact metrics that consider not only the raw
number of citations received by a scientic agent, but also
the “importance” of the journals that issued them (assigning
weights to the bibliographic citations) (6, 7). In practice, the
scientic literature is considered as a network of scholarly
articles, connected by citations. The “importance” of each
journal is computed recursively, by the number of citations
received from other “important” journals. Such procedure,
used for calculating EFS, AIS and SJR, belongs to the group
of eigenvector centrality methods and is now feasible thanks
to powerful computational systems similar to the PageRank
algorithm, developed by the creators of Google (6, 7).
Secondly, different citation-based metrics are used, some
to compare the performance of journals, others to assess how
often researchers are cited and then rank their scientic pro-
ductivity. As an example, the h-index was proposed by Hirsch
(8) to rank authors according to their rank-ordered citation
distributions, and only later was it extended to scientic jour-
nals (12). We think that the characteristics of this index make
it more suitable for the former aim.
Many drawbacks of the h-index have been discussed in
recent years (13), for example: (i) once an article belongs to
the h-dening class, it is completely unimportant whether or
not these papers continue to be cited; (ii) h-index is highly
dependent upon the activity length and can only rise; (iii) it is
inuenced by the journal size; (iv) there remains a variation
in citation related to different subject areas. Overall, h-index
seems to oversimplify the complexity of this eld and lead
to misunderstanding (3). With the aim of compensating these
weaknesses (13), a number of variants have been proposed,
but at present none has gained currency.
Overall, there is a need better to understand some basic
characteristics of these new indicators, whereas a detailed
discussion of their technical aspects is beyond the scope of
this report. We will briey discuss here the most interesting
correlations between journal indicators, and journal ranking
according to these indicators.
Correlations between indicators
Correlations should be interpreted with special care, particu-
larly when few measures with a restricted range of variability
are analysed. The JIF showed a good correlation (> 0.70) with
5Y-JIF and a fair-to-moderate correlation with AIS and SJR.
In addition, the following good correlations have been found:
5Y-JIF with AIS and SJR; EFS with the two h-indexes; AIS
with SJR; and between the two h-indexes. All other correla-
tions were low (< 0.45).
These ndings were expected (14, 15), because JIF, 5Y-JIF,
AIS and SJR are measures of average citation impact per
paper (and should, all else being equal, be independent of
journal size), while EFS is a measure of total citation impact
(which scales with the size of the journal). On the other hand,
the high correlation between EFS and h-indices is reasonable
(16), even if EFS and an h-index are not interchangeable (17).
Proponents of the h-indexes claim that this indicator reects
both the number of publications and the number of citations
per publication. Conversely, EFS seems to express composite
information (about total citation impact) that is complemen-
tary to that of JIF, 5Y-JIF, SJR or AIS (about average citation
impact per paper) (18).
For the above reasons, the good correlations of the 5Y-JIF
with the SJR and AIS, and between the SJR and AIS, are not
Table II. Values (column ranking) of the 15 top journals in the JCR Rehabilitation category, in alphabetical order (the ofcial US National Library
of Medicine-catalogue abbreviations are used)
Journal JIF
5Y-JIF
EFS
AIS
SJR h-index1 h-index2
Am J Phys Med Rehabil 1.556 (13) 2.014 (13) 0.00728 (6) 0.560 (13) 0.117 (9) 44 (7) 26 (8)
Arch Phys Med Rehabil 2.184 (6) 2.761 (5) 0.02677 (1) 0.784 (7) 0.155 (5) 84 (1) 47 (1)
Aust J Physiother 1.709 (12) 2.709 (7) 0.00275 (14) 0.990 (2) 0.139 (6) 26 (14) 20 (14)
Brain Inj 1.533 (15) 1.925 (14) 0.00608 (7) 0.458 (14) 0.089 (15) 47 (4) 25 (10)
Clin Rehabil 1.767 (11) 2.546 (9) 0.00805 (4) 0.723 (8) 0.121 (8) 46 (5) 31 (4)
Disabil Rehabil 1.555 (14) 2.056 (12) 0.01078 (2) 0.564 (12) 0.099 (13) 43 (8) 33 (3)
IEEE T Neural Syst Rehabil Eng 2.417 (3) 3.299 (3) 0.00579 (8) 0.891 (4) 0.248 (1) 51 (3) 39 (2)
J Electromyogr Kinesiol 1.995 (9) 2.373 (11) 0.00540 (9) 0.654 (10) 0.102 (11) 42 (9) 28 (7)
J Head Trauma Rehabil 2.391 (4) 3.639 (2) 0.00420 (12) 0.926 (3) 0.229 (2) 41 (10) 26 (8)
J Neuroeng Rehabil 2.115 (7) – 0.00257 (15) – 0.112 (10) 16 (15) 11 (15)
J Orthop Sports Phys Ther 2.482 (2) 2.434 (10) 0.00499 (10) 0.625 (11) 0.094 (14) 46 (5) 25 (10)
J Rehabil Med 1.882 (10) 3.027 (4) 0.00778 (5) 0.849 (5) 0.129 (7) 39 (11) 25 (10)
Man Ther 2.319 (5) 2.686 (9) 0.00318 (13) 0.690 (9) 0.100 (12) 30 (13) 23 (13)
Neurorehabil Neural Repair 5.398 (1) 4.836 (1) 0.00486 (11) 1.096 (1) 0.228 (3) 34 (12) 29 (6)
Phys Ther 2.082 (8) 2.742 (6) 0.00927 (3) 0.802(6) 0.175 (4) 63 (2) 31 (4)
JCR: Journal Citation Reports; JIF: JCR Journal Impact Factor; 5Y-JIF: 5-year Journal Impact Factor; EFS: Eigenfactor score; AIS: Article Inuence
Score; SJR: SCImago Journal rank indicator; h-index1: h-index calculated by SCImago; h-index2: h-index calculated by Web of Science with a
5-year window.
J Rehabil Med 43

474
F. Franchignoni and S. Muñoz Lasa
surprising. All these indicators divide citations of a journal
during a specic time period by the number of articles pub-
lished by the journal in the same period. The larger window of
analysis of the 5Y-JIF (5 years) in comparison with the JIF (2
years) is probably responsible for its higher correlation with
the SJR (3 years) and the AIS (5 years). The JIF is a well-
known measure, but with several drawbacks: e.g. very skewed
distribution of article citedness (usually, 15% of a journal’s
articles collect 50% of the citations); heavy dependence on
peculiarities and practices of publication in different subject
areas (eld effect), and on how many journals are indexed in
the subject; high correlation with mean time from submission
to publication and citation pattern (including the speed with
which authors begin citing articles) (1). Moreover, the JIF is
prone to different kinds of manipulation (2, 19). The 5Y-JIF
does not solve the majority of these problems: enlarging the
target window could be positive for some disciplines (includ-
ing PRM), but does not change the essence of the indicator.
Conversely, the main advantages of the SJR over the JIF (and
the 5Y-JIF) should lie in its methodology of score estimation:
in particular, the weight attributed to citations (depending on
the “importance” of the citing journal), but perhaps also the
way of handling self-citations (which is not included) (10). A
study by Bollen et al. (11), using principal component analysis
to assess 39 different impact measures, grouped the SJR and the
JIF together as measures of “citation normalized per document”
and “popularity” (referred as the number of citations, equally
counted, without consideration of the origin) (9), in spite of
the fact that the SJR should also explicitly “transfer prestige
from a journal to another one” (see www.scimagojr.com/
SCImagoJournalRank.pdf). A similar nding was reported by
Leydesdorff (3). However, the Scopus database (SJR) includes
a substantially larger collection of journals than the WoS (JIF,
EFS, etc.) and PubMed, originating from more countries and
published in a greater variety of languages (4, 5). Thus, in
this regard it could be assumed that the SJR provides a more
comprehensive estimation of the scientic impact of journals
at the worldwide level than the WoS (and JIF), particularly
those published in non-English languages. In addition, SJR
is an open access resource, while WoS (JIF) requires a paid
subscription (10).
Journal ranking
Journal ranking is very important and is closely watched by
researchers, editors, publishers, librarians and others. In the
world of journal publishing (and in many other contexts) being
ranked number 1 or 4 according to a certain index is critical,
and dropping even a few rank positions may be perceived by
some as the difference between winning the gold medal in the
Olympic games and being overlooked by all (20).
In Table II it is clear that there are substantial ranking dif-
ferences (more than 5 rank positions) between indicators,
and it is impossible to dene the “standing” of a scientic
journal using a single indicator. The top ranking is achieved
by Neurorehabilitation and Neural Repair according to the
JIF, 5Y-JIF and AIS; by Archives of Physical Medicine & Re-
habilitation according to the EFS and the two h-indexes; and
by IEEE Transactions on Neural Systems and Rehabilitation
Engineering according to the SJR. In spite of being in the
same “Rehabilitation” category of the JCR, the 3 top journals
have different missions, areas of interest and audience, and
probably different publication and citation dynamics. Each of
these factors can inuence 1 or more indicators.
Examining these ranking more closely, the use of EFS rank-
ing as an indicator of journal “inuence” corresponds with
the proposals of the Consensus Committee on “International
Rehabilitation Journals” of the European Society of Physical
and Rehabilitation Medicine (ESPRM). In fact, the Commit-
tee suggested 5 out of the rst 6 journals listed in Table II in
order of their EFS ranking as rst choice for publication by
European PRM researchers (in alphabetical order: American
Journal of Physical Medicine & Rehabilitation, Archives of
Physical Medicine & Rehabilitation, Clinical Rehabilitation,
Disability and Rehabilitation, and Journal of Rehabilitation
Medicine) (21). The Committee’s choice clearly acknowledges
the top standing of these journals. The sixth journal in EFS
ranking (Physical Therapy) was not taken into account by the
Committee, being a leading journal, but of a different (although
allied) discipline. An external validation of the Committee’s
decisions came from a bibliometric survey (21) showing that
the 5 top journals selected were in the rst 5 positions in
terms of recent publications by 10 randomly-chosen members
of the European Academy of PRM, coming from 9 different
European countries.
These ndings appear to be an indirect conrmation of the
importance of those journals and of the ability of the EFS to
capture their citation interdependence and global “inuence”,
as a calibrated mix of size (i.e. how many citations a journal
receives, irrespective of who made the citation) and weighted
impact (i.e. giving greater importance to citations appearing
in highly cited journals).
Summary
In summary, according to the recent literature (9, 22), the JIF,
5Y-JIF and SJR (and to a lesser extent the AIS) should be
considered as a metric of average citation impact per paper
(22). Although further validation is warranted, the SJR seems to
represent a serious alternative to the JIF (6, 10), because it uses
innovative impact metrics that take into account not only the
number of citations, but also assign weight to citations based
on the “importance” of the journals that issued them.
On the other hand, the EFS measures the total citation im-
pact, and appears to be able satisfactorily to reect the global
journal “inuence” (23). Conversely, it has been demonstrated
that the JIF does not correlate with researchers’ perceptions of
the relative importance of journals as media for communicating
important biomedical research results (24).
From a nal user perspective, many other indicators do not
appear to add much, are difcult to understand, and are closely
connected with technical choices (e.g. depth and length of
coverage in the underlying databases, different weighting of
their software, etc.). Their validation and renement are still
J Rehabil Med 43

475
Bibliometric indicators and core journals in PRM
in progress. In addition, all bibliometric indicators are depend-
ent on the citation database used (WoS, Scopus, etc.) (4, 5);
their transparency and traceability needs to be enhanced; and
justication for some mathematical procedures for calculating
them (including normalization methods, and statistics based
on arithmetic averages of a highly skewed distribution) is still
missing (25).
A limitation of this report is that we took into account only
the rst 15 journals in the Rehabilitation category of the
JCR – Science Edition 2009 (WoS), ranked by the JIF. These
journals (Table II) are also all indexed in Scopus, but 6 in the
category “Rehabilitation” (that contains 90 items), 4 in “Or-
thopedics and Sports Medicine”, 2 in “Neurology – clinical”,
and 3 in “Health Professions – miscellaneous”. This shows
that delineating a science eld is a complex problem (26, 27)
and the JCR subject categories lack an analytical base and are
not regularly updated, whereas alternative and more sophis-
ticated classication schemes are available nowadays (28,
29). Moreover, we do not have a universally accepted, golden
standard in this eld to calibrate any new measures, and these
measures were calculated for different citation datasets, so that
it may be difcult to distinguish the true characteristics of an
indicator from the peculiarities of the dataset from which it
was calculated.
Conclusion
In conclusion, the concept of scientic impact is multi-dimen-
sional and cannot be adequately captured by a single indicator.
Probably, for analysing the scientic relevance of journals a
good choice could be a combination of just a few indicators,
able to reect both the average impact of the papers and the
size component.
In fact, the measures of average “impact per paper” (such as
the JIF and the SJR) are not positioned at the core of the con-
struct “overall standing of a scientic journal” (11, 22). Other
new measures show potentially useful complementarities with
them and merit further attention. For example, the measures
of “total citation impact” of a journal (weighted according
to the importance of the citing journals) (such as the EFS,
or simply “total cites”) seem to better express the ‘inuence’
(sometimes referred to as “prestige”) of a journal (17, 22, 23,
30), and to better correspond with a general understanding of
journal status, as captured by eld experts.
We have tried to add new insights to the ongoing discussion
regarding the suitability of bibliometric indicators, particularly
when applied in PRM. Further studies are needed to conrm
the generalizability of these ndings to other elds, and we
hope that this report may lead to further debate on this topic
of growing interest.
There are 3 qualications to this discussion, which should be
taken into account. First, these bibliometric indicators apply to
the journals and not to the individual papers (or authors). Better
ways to analyse the “performance” of a paper exist, including to
tally the number of citations that the paper itself received (25,
31), through WoS, Scopus or Google scholar (32). Secondly,
citation data are not the only way to quantitatively measure
the values that a journal or a paper offers: for example, direct
measures of readership and usage (i.e. coming from usage log
data) can also be considered (7). Finally, all these indicators
represent ways of ranking each scholarly journal within the
moving world of science, but authors should select the journal
that best matches the nature and potential readership of their
research, considering the mission statement of the journal,
the author guidelines, the composition of the editorial board,
and the journal’s publishing history, in order to establish that
the scientic or clinical areas of interest of the journal reect
the desired target population (33, 34). The ranking of journals
(as well as of papers, authors, institutions etc.) should be done
solely with the aim of improving our ability to search and do
science, and not for measuring the quality of output of indi-
viduals, research groups, or universities. Citation analysis,
however sophisticated it may be, cannot be a substitute for
critical reading and expert judgement.
Conversely, as West et al. (14) stated, “where ranking sys-
tems provide narrow-minded administrators and faculty with
an excuse to avoid hard work and deep thought, they may even
be harmful to the functioning of academia”.
COMPETING INTERESTS
FF is Associate Editor of the Journal of Rehabilitation Medicine, Senior
Editor of the European Journal of Physical and Rehabilitation Medicine
(formerly Europa Medicophysica), and a member of the Editorial Board of
the International Journal of Rehabilitation Research; Portuguese Journal
of Physical and Rehabilitation Medicine; Rehabilitacija; Physikalische
Medizin, Rehabilitationsmedizin, Kurortmedizin/Journal of Physical and
Rehabilitation Medicine (Stuttgart); and Giornale Italiano di Medicina
del Lavoro e Ergonomia. SML has no competing interest to declare.
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