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Contents
Introduction to research metrics (h-index, Impact Factor, etc) 1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Impact factor – definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Limitations and Biases of the Impact Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Article Influence Score (AIS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
SCImago Journal Rank (SJR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
CiteScore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Source Normalized Impact per Paper (SNIP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
H-index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Reference list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Finding impact factors for journals 7
Evaluation of Journals in Scopus 13
How to find h-index in Web of Science 16
How to find h-index in Scopus 19
Introduction to research metrics (h-index, Impact
Factor, etc)
Introduction
An integral part of researchers’ duties in a research institution is not only to publish their results but
also to report the results for the purpose of evaluating their research. For this purpose mathematical
and statistical methods are applied to gain a quantitative evaluation of research results. These methods
process data provided by authors about their publications and the citation rates of their works from the
Journal Citation Reports (JRC) and Scopus databases.
In the JCR database, impact factor serves for this purpose, and since 2017, another key metric,
Article Influence Score (AIS), has been used by the Research, Development and Innovation Council.
Both databases count the Hirsch index, also called the h-index, to evaluate the quality of a given
author’s publication activity.
Journal Citation Reports Subject of metrics Scopus Subject of metrics
Impact factor Journal CiteScore Journal
Article Influence Score Article SNIP Journal
H-index Author SJR Journal
h-index Author
Table 1 An overview of metrics and subjects of their analysis in JCR and Scopus
Impact factor – definition
Impact factor is one of the tools for quantitatively evaluating research results. This factor measures the
average citation rate of articles in a given journal for a specific period of time. It is defined as follows:
the ratio of citations recorded in the given (evaluated) year to all articles published in a given journal in
the preceding two years to the total number of all those articles (Fig. 1). Impact factor values may be
found in the JCR database.
Fig. 1 Impact factor of the journal Blood in 2017 (source: Journal Citation Reports, 2019)
Limitations and Biases of the Impact Factor 2
Limitations and Biases of the Impact Factor
ˆ While the impact factor is a time-tested indicator evaluating the quality of journals, it is completely
unsuitable for assessing the quality of individual articles or researchers themselves.
ˆ Journals from different fields cannot be compared based on their values of impact factor, because
every field has different publication conventions and citation potential.
ˆ The language of the publications may also influence the value of the impact factor. A journal
publishing in another language than English is commonly less cited despite the fact that it may be
a periodical of high quality.
ˆ The type of documents the journal commonly publishes, e.g. reviews, research articles or case
reports, is another variable that affects the value of the impact factor.
ˆ The type of access to full texts also affects the impact factor. Open-access journals have a larger
citation potential, because their articles reach a readership more quickly and without any barriers,
whether financial or technical.
ˆ A two-year period for calculating the impact factor may be too short, because to prepare publications
citing the respective article may take longer in some fields. For that reason a five-year impact
factor was added to help the user gain a more precise picture about the journal’s citation rate.
ˆ The value of the impact factor is very often influenced by a small number of highly-cited papers
in a journal where the majority of articles does not reach the value of the impact factor calculated
(see Figures 2 and 3).
Fig. 2 Distribution of citations with regard to the impact factor value of the journals Nature and Science
(source: Callaway, 2016)
Article Influence Score (AIS) 3
Fig. 3 Distribution of citations with regard to the impact factor value of the journal PLoS (source:
Callaway, 2016)
Article Influence Score (AIS)
AIS is a metric which is subject to a bibliometric analysis performed by the Research Development and
Innovation Council (RVVI). Compared to impact factor, AIS is a more sophisticated metric, because it
calculates the value of the average influence of every article in a journal for a five-year period (roughly
similar to five-year impact factor). A score greater than 1 indicates that each article in a specific journal
has an above-average influence, while a score smaller than 1 means that articles in a journal have belowaverage
influence. AIS values may be found in the JCR database.
SCImago Journal Rank (SJR)
SJR is a sophisticated metric whose main principle is similar to Google Page Rank (a number assigned
by Google to every URL that expresses the credibility and importance of the given website). SJR takes
into consideration the importance of citations (i.e. not all citations are equally important). The main
principle for calculating SJR is an algorithm that measures how many times the journal was cited by
other journals and what importance these individual citations have. The importance of citations is
derived from the prestige of the journal from which the citations come. The aim of SJR is to facilitate
a relevant comparison of journals’ quality from different fields. In the bibliometric analysis carried out
by the Research Development and Innovation Council, this metric is a key tool for evaluating research
organisations in the Czech Republic.
CiteScore
CiteScore is a metric calculated in the same way as impact factor with the difference that the number
of articles and their citations are taken from the last three years and not two as in the case of impact
factor.
Source Normalized Impact per Paper (SNIP) 4
Fig. 4 Calculating CiteScore for a journal for the year 2016 (source: Elsevier, 2019)
Source Normalized Impact per Paper (SNIP)
SNIP designed by Henk Moed from the Centre for Science and Technology Studies (CTWS) is another
indicator in Scopus. It expresses the ratio of an average citation of an article in a given journal to the
citation potential of the field (the probability that a document will be cited in the given field). The SNIP
metric helps authors determine which journals in their field are of high quality. It may also serve a key
indicator when deciding where to publish.
SNIP is calculated with a simple formula:
SNIP =
IPP(journal’s impact per publication)
DCP(Database Citation Potential)
The IPP is a value computed in a similar way like impact factor, but IPP works with data from
the last three years (not just two as in the case of impact factor).
IPP2016 =
number of citations in 2016 to articles between 2013-2015 in journal XY
number of all articles published between 2013-2015 in journal XY
The result of IPP provides information on how many times every article published in the XY
journal in the years 2013–2015 was cited in 2016.
DCP is an abbreviation for the citation potential of a journal in its respective field. The value of
DCP is calculated as the ratio of the citation potential of a journal in the database to the median value
of a journal in the same field. Obtaining these details is very demanding, and it must be carried out with
the help of computer technology.
DCP2016 =
citation potential of journal XY in database
median value of journal XY in its field in database
The median of the journal’s field is the median value of citation potential in the respective field.
H-index
Hirsch index (h-index) is an indicator assessing the publication activity of individual authors or groups
of authors (e.g. within an institution).
H-index is calculated for journals as well, because it may be determined for any set of records.
However, this metric is primarily connected with assessing the publication performance of an author as
an individual.
Reference list 5
Note, that the value of h-index may differ based on which database you use for the computation,
because not every database records the same journals and their volumes.
H-index indicates how many articles received a higher number of citations than their order number
(publications are in a descending order according to the number of citations they received). H-index equals
the order number of the article which received the same or a higher number of citations than its order
number in the list – see Fig. 5.
Fig. 5 A sample of computing the h-index with the result of h-index = 8
Reference list
1. Callaway E. Beat it, impact factor! Publishing elite turns against controversial metric. Nature.
2016;535(7611):210-211. doi:10.1038/nature.2016.20224. Accessed April 16, 2019.
2. Colledge L, de Moya-Aneg´on F, Guerrero-Bote V, L´opez-Illescas C, El Aisati M, Moed H. SJR and
SNIP: two new journal metrics in Elsevier’s Scopus. Serials: The Journal for the Serials Community.
2010;23(3):215-221. doi:10.1629/23215. Accessed February 6, 2019.href
3. Grzybowski A. Impact factor - benefits and limitations. Acta Ophthalmologica. 2015;93(3):201-202.
doi:10.1111/aos.12579. Accessed March 3, 2019.href
4. Kreiner G. The Slavery of the h-index—Measuring the Unmeasurable. Frontiers in Human Neuroscience.
2016;10. doi:10.3389/fnhum.2016.00556. Accessed March 20, 2019
5. Kurmis AP. Understanding the limitations of the journal impact factor. J Bone Joint Surg Am.
2003;85-A(12):2449-2454. Accessed March 20, 2019.
6. Schreiber M. An empirical investigation of theg-index for 26 physicists in comparison with thehindex,
theA-index, and theR-index. Journal of the American Society for Information Science and
Technology. 2008;59(9):1513-1522. doi:10.1002/asi.20856. Accessed April 11, 2019.
7. Tregoning J. How will you judge me if not by impact factor?Nature. 2018;558(7710):345-345.
doi:10.1038/d41586-018-05467-5. Accessed April 11, 2019.
8. Van Noorden R. Controversial impact factor gets a heavyweight rival. Nature. 2016;540(7633):325-
326. doi:10.1038/nature.2016.21131. Accessed March 19, 2019.
9. Vanclay JK. Bias in the journal impact factor. Scientometrics. 2009;78(1):3-12. doi:10.1007/s11192-
008-1778-4. Accessed February 12, 2019.
Reference list 6
10. Description of Scimago Journal Rank Indicator. [object Object]. Published 2007. Accessed March
17, 2019.
11. Clarivate Analytics. The Clarivate Analytics Impact Factor. [object Object]. Accessed February
27, 2019
12. CWTS Journal Indicators - Methodology. http://www.journalindicators.com/methodology. Accessed
February 6, 2019.
13. How are CiteScore metrics used in Scopus? - Scopus: Access and use Support Center. https:
//service.elsevier.com/app/answers/detail/a id/14880/supporthub/scopus/. Accessed March 18,
2019.
14. InCites Help. Journal Impact Factor. http://help.incites.clarivate.com/inCites2Live/indicatorsGroup/
aboutHandbook/usingCitationIndicatorsWisely/jif.html. Accessed March 3, 2019.
15. InCites Journal Citation Reports Help. Article Influence Score. http://help.incites.clarivate.com/
incitesLiveJCR/glossaryAZgroup/g4/7790-TRS.html. Accessed April 3, 2019.
16. SNIP. Elsevier. https://journalinsights.elsevier.com/journals/0301-0104/snip. Accessed April 16,
2019.
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We recommend determining the Publons identifier for managing your publication activities, and
then you have to perform the process described above just once. The only thing you would need to do
afterwards is “maintenance” every year and add new articles to the Web of Science database.
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We recommend determining the ORCID identifier for managing your publication activities, and
then you have to perform the process described above just once. The only thing you would need to do
afterwards is “maintenance” every year and add new articles in the Scopus database.