7,305 research outputs found
Field-normalized citation impact indicators and the choice of an appropriate counting method
Bibliometric studies often rely on field-normalized citation impact
indicators in order to make comparisons between scientific fields. We discuss
the connection between field normalization and the choice of a counting method
for handling publications with multiple co-authors. Our focus is on the choice
between full counting and fractional counting. Based on an extensive
theoretical and empirical analysis, we argue that properly field-normalized
results cannot be obtained when full counting is used. Fractional counting does
provide results that are properly field normalized. We therefore recommend the
use of fractional counting in bibliometric studies that require field
normalization, especially in studies at the level of countries and research
organizations. We also compare different variants of fractional counting. In
general, it seems best to use either the author-level or the address-level
variant of fractional counting
A review of the literature on citation impact indicators
Citation impact indicators nowadays play an important role in research
evaluation, and consequently these indicators have received a lot of attention
in the bibliometric and scientometric literature. This paper provides an
in-depth review of the literature on citation impact indicators. First, an
overview is given of the literature on bibliographic databases that can be used
to calculate citation impact indicators (Web of Science, Scopus, and Google
Scholar). Next, selected topics in the literature on citation impact indicators
are reviewed in detail. The first topic is the selection of publications and
citations to be included in the calculation of citation impact indicators. The
second topic is the normalization of citation impact indicators, in particular
normalization for field differences. Counting methods for dealing with
co-authored publications are the third topic, and citation impact indicators
for journals are the last topic. The paper concludes by offering some
recommendations for future research
A categorization of arguments for counting methods for publication and citation indicators
Most publication and citation indicators are based on datasets with
multi-authored publications and thus a change in counting method will often
change the value of an indicator. Therefore it is important to know why a
specific counting method has been applied. I have identified arguments for
counting methods in a sample of 32 bibliometric studies published in 2016 and
compared the result with discussions of arguments for counting methods in three
older studies. Based on the underlying logics of the arguments I have arranged
the arguments in four groups. Group 1 focuses on arguments related to what an
indicator measures, Group 2 on the additivity of a counting method, Group 3 on
pragmatic reasons for the choice of counting method, and Group 4 on an
indicator's influence on the research community or how it is perceived by
researchers. This categorization can be used to describe and discuss how
bibliometric studies with publication and citation indicators argue for
counting methods
A review of the characteristics of 108 author-level bibliometric indicators
An increasing demand for bibliometric assessment of individuals has led to a
growth of new bibliometric indicators as well as new variants or combinations
of established ones. The aim of this review is to contribute with objective
facts about the usefulness of bibliometric indicators of the effects of
publication activity at the individual level. This paper reviews 108 indicators
that can potentially be used to measure performance on the individual author
level, and examines the complexity of their calculations in relation to what
they are supposed to reflect and ease of end-user application.Comment: to be published in Scientometrics, 201
Investigating the interplay between fundamentals of national research systems: performance, investments and international collaborations
We discuss, at the macro-level of nations, the contribution of research
funding and rate of international collaboration to research performance, with
important implications for the science of science policy. In particular, we
cross-correlate suitable measures of these quantities with a
scientometric-based assessment of scientific success, studying both the average
performance of nations and their temporal dynamics in the space defined by
these variables during the last decade. We find significant differences among
nations in terms of efficiency in turning (financial) input into
bibliometrically measurable output, and we confirm that growth of international
collaboration positively correlate with scientific success, with significant
benefits brought by EU integration policies. Various geo-cultural clusters of
nations naturally emerge from our analysis. We critically discuss the possible
factors that potentially determine the observed patterns
A critical cluster analysis of 44 indicators of author-level performance
This paper explores the relationship between author-level bibliometric
indicators and the researchers the "measure", exemplified across five academic
seniorities and four disciplines. Using cluster methodology, the disciplinary
and seniority appropriateness of author-level indicators is examined.
Publication and citation data for 741 researchers across Astronomy,
Environmental Science, Philosophy and Public Health was collected in Web of
Science (WoS). Forty-four indicators of individual performance were computed
using the data. A two-step cluster analysis using IBM SPSS version 22 was
performed, followed by a risk analysis and ordinal logistic regression to
explore cluster membership. Indicator scores were contextualized using the
individual researcher's curriculum vitae. Four different clusters based on
indicator scores ranked researchers as low, middle, high and extremely high
performers. The results show that different indicators were appropriate in
demarcating ranked performance in different disciplines. In Astronomy the h2
indicator, sum pp top prop in Environmental Science, Q2 in Philosophy and
e-index in Public Health. The regression and odds analysis showed individual
level indicator scores were primarily dependent on the number of years since
the researcher's first publication registered in WoS, number of publications
and number of citations. Seniority classification was secondary therefore no
seniority appropriate indicators were confidently identified. Cluster
methodology proved useful in identifying disciplinary appropriate indicators
providing the preliminary data preparation was thorough but needed to be
supplemented by other analyses to validate the results. A general disconnection
between the performance of the researcher on their curriculum vitae and the
performance of the researcher based on bibliometric indicators was observed.Comment: 28 pages, 7 tables, 2 figures, 2 appendice
Constructing bibliometric networks: A comparison between full and fractional counting
The analysis of bibliometric networks, such as co-authorship, bibliographic
coupling, and co-citation networks, has received a considerable amount of
attention. Much less attention has been paid to the construction of these
networks. We point out that different approaches can be taken to construct a
bibliometric network. Normally the full counting approach is used, but we
propose an alternative fractional counting approach. The basic idea of the
fractional counting approach is that each action, such as co-authoring or
citing a publication, should have equal weight, regardless of for instance the
number of authors, citations, or references of a publication. We present two
empirical analyses in which the full and fractional counting approaches yield
very different results. These analyses deal with co-authorship networks of
universities and bibliographic coupling networks of journals. Based on
theoretical considerations and on the empirical analyses, we conclude that for
many purposes the fractional counting approach is preferable over the full
counting one
The Leiden Ranking 2011/2012: Data collection, indicators, and interpretation
The Leiden Ranking 2011/2012 is a ranking of universities based on
bibliometric indicators of publication output, citation impact, and scientific
collaboration. The ranking includes 500 major universities from 41 different
countries. This paper provides an extensive discussion of the Leiden Ranking
2011/2012. The ranking is compared with other global university rankings, in
particular the Academic Ranking of World Universities (commonly known as the
Shanghai Ranking) and the Times Higher Education World University Rankings.
Also, a detailed description is offered of the data collection methodology of
the Leiden Ranking 2011/2012 and of the indicators used in the ranking. Various
innovations in the Leiden Ranking 2011/2012 are presented. These innovations
include (1) an indicator based on counting a university's highly cited
publications, (2) indicators based on fractional rather than full counting of
collaborative publications, (3) the possibility of excluding non-English
language publications, and (4) the use of stability intervals. Finally, some
comments are made on the interpretation of the ranking, and a number of
limitations of the ranking are pointed out
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