NEW WAYS TO TRACK
SCHOLARLY
PRODUCTIVITY:
THE H- AND G-INDICES
WHAT IS THE H-INDEX
“A scientist has index h if h of his/her Np papers
have at least h citations each, and the other
(Np − h) papers have no more than h citations
each.” [Hirsch, 2005]
Shorter version:
“an index of h has published h papers each of
which has been cited by others at least h times.”
WHO AND WHY
Created by Jorge E. Hirsch, a physicist at
UC-San Diego, to determine theoretical
physicists' relative quality.
 The h-index grows as citations accumulate
and thus it depends on the ‘academic age’ of
a researcher.

RANK=CITATIONS
•Find all your papers.
•Sort them by citation count.
•Scroll down until the
number of citations equals
the number of the paper
(in the example chart to your
left, n=8).
BENEFITS OF THE H-INDEX
It is quantitative.
 It takes into account the QUANTITY of wellcited publications.
 The index is intended as a tool to evaluate
researchers in the same stage of their careers. It
is not meant as a tool for historical comparisons.
 Since the h-index increases with time, initial
work that was published early is still relevant.
 Only the most highly cited articles contribute to
the h-index.

PROBLEMS WITH THE H-INDEX
Self citations are in the list.
 Cross field comparison is difficult.
 As your h-index number increases, it becomes harder
to increase it further.
 The lowest citation thresholds are in the Social
Sciences, Computer Science, and Multidisciplinary
Sciences.
 The h-index does not account for the number of
authors of a paper.
 The h-index gives books the same count as articles
making it difficult to compare scholars in fields that
are more book-oriented.

WHAT IS THE G-INDEX
“Given a set of articles ranked in decreasing
order of the number of citations that they
received, the g-index is the (unique) largest
number such that the top g articles received
(together) at least g2 citations.” [Egghe, 2006]
Shorter version:
“this means that an author that produces n
articles should have, on average, n citations for
each of them, in order to have a g-index of n.”
WHO AND WHY
Created by Leo Egghe, Universiteit Hasselt,
Antwerpen.
 g is expected to be a good correlation with the total
number of citations an author has received, while h
correlates with the highest number of citations which
the most quoted paper brings to his author.
Accordingly g is often greater than h.

In 2010, the High Impact Universities Research
Performance Index (RPI) was developed,
analyzing research performance for 1,000
universities and 5,000 constituent faculties.
RANKING CITATIONS
•The g-index describes the consistency and
quality of an institution faculty's research output.
•Determine the g-index by ranking an individual’s
publications in terms of the number of citations
that each publication received. The top g
publications should have received, in total, at
least g^2 citations.
BENEFITS OF THE G-INDEX




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It is quantitative.
The g-index gives more weight to highly cited
articles.
The total number of documents does not limit
the value of the index.
The g-index might be more adequate than the
h-index for assessing selective scientists
**Researchers with selective publication
strategies are those who do not publish a very
high number of documents but who do attain
a high impact
PROBLEMS WITH THE G-INDEX
Self citations are in the list.
 Cross field comparison is difficult.

HOW DO YOU FIND YOUR H- AND G-INDEX?
Web of Science
 Harzing’s Publish or Perish (uses Google Scholar)
 Google Scholar


Caveats with each db
Each database is likely to produce a different h for the
same scholar, because of different coverage.
 Google Scholar has more citations but more chaff,
however, the smaller citation collections are more
accurate as to actual published works.

SAMPLE: ANTOINE BERTINELLI

Web of Science

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65 papers
499 citations (no self-citations)
Cites/paper= 7.15
Authors/paper: 1.80
h-index = 13
g-index = 18
Harzing Publish or Perish

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68 papers [-3 lists/rosters = 65 papers total]
577 citations [includes self-citations]
Cites/year: 11.78
Cites/paper = 8.88
Authors/paper: 1.80
h-index= 14
g-index = 22
BOTH ARE NECESSARY
The existence of highly cited papers is heavily
valued by the g-index.
 The h-index values a stable profile in the scientific
performance of scientists but penalizes selective
publication strategies.

EXAMPLE: REAL PERSON:
WOS
Results found:
86
Sum of the Times Cited [?] :
610
Sum of Times Cited without self596
citations [?] :
Citing Articles[?] :
590
Citing Articles without self-citations [?]
579
:
Average Citations per Item [?] :
7.09
h-index [?] :
13
o Search on an individual’s name, mark all the citations reported
in WOS, and then click on ‘Create citation report’.
o Each report is accompanied by
o Two charts, showing ‘published items in each year’ and
‘citations in each year’
o Searches only what is captured in WoS.
o Does not include ephemera or ghost citations (Google does).
EXAMPLE: REAL PERSON:
HARZING’S PUBLISH OR PERISH
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Query date: 2013-01-28
h-index: 17
Papers: 63
g-index: 25
Citations: 776
e-index: 15.65
Years: 56
hc-index: 4
•Cites/year: 13.86
•hI-index: 8.50
•Cites/paper: 12.32/7.0/1 (mean/median/mode)
•hI,norm: 12
•Cites/author: 501.66
•hm-index: 12.58
•Papers/author: 44.92
• Authors/paper: 1.76/1.0/1 (mean/median/mode)
o Searches Google Scholar and returns results calculating the
h- and g-indices for individuals and journals.
o Provides links from the cited work to the citing works
oCan be ported in Excel for further analysis
EXAMPLE: REAL PERSON:
GOOGLE SCHOLAR UNIVERSAL GADGET
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Citations for 'SAMPLE FACULTY' : 777
Cited Publications: 63
H-Index: 17
However, millions of Google Scholar (GS) records
have erroneous metadata, as well as inflated
publication and citation counts.
GS lumps together the number of master records
(created from actual publications), and the number of
citation records (distinguished by the prefix:
[citation]) when reporting the total hits for author
name search.
It is important to check and refine the data that the
gadget performs calculations on by clicking on the
“view publications” link and not take the returns at
face value.
HIRSCH (OF THE H INDEX) SAYS:

Note Qualifier is for the field of Physics,
“an h index of 20 after 20 years of scientific
activity characterizes a successful scientist”
 “an h index of 40 after 20 years of scientific
activity characterizes outstanding scientists
likely to be found only at the top universities or
major research laboratories”
 “an h index of 60 .. after 20 years …characterizes
truly unique individuals”

Hirsch JE. An index to quantify and individual’s scientific research
output. PNAS 2005;102:16569-72.