VOL. 21 NO. 3, SEPTEMBER, 2016
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Simultaneous and comparable numerical indicators of
international, national and local collaboration practices in
English-medium astrophysics research papers
David I. Méndez and M. Ángeles Alcaraz
Abstract
Introduction. We report an investigation on collaboration
practices in research papers published in the most prestigious
English-medium astrophysics journals.
Method. We propose an evaluation method based on three
numerical indicators to study and compare, in absolute terms,
three different types of collaboration (international, national and
local) and authors' mobility on the basis of co-authorship.
Analysis.We analysed 300 randomly selected research papers in
three different time periods and used the student's t-test to
determine whether the paired two-sample differences observed
were statistically significant or not.
Results. International collaboration is more common than
national and local collaboration. International, national and local
authors' mobility and intra-national collaboration do not seriously
affect the indicators of the principal levels of collaboration.
International collaboration and authors' mobility are more
relevant for authors publishing in European journals, whereas
national and intra-national collaboration and national mobility
are more important for authors publishing in US journals.
Conclusions. We explain the observed differences and patterns in
terms of the specific scope of each journal and the socio-economic
and political situation in both geographic contexts (Europe and the
USA). Our study provides a global picture of collaboration
practices in astrophysics and its possible application to many other
sciences and fields would undoubtedly help bring into focus the
really big issues for overall research management and policy.
Introduction
Scientific collaboration, understood as 'a means to advance
research' (Pao, 1992, p.99), has existed since the beginning of
change font
science and it consists of the specific scientific activities
(observation, data collection, experimentation, analysis,
interpretation and publication) performed by scientists
working together on a common research project. Due to its
importance, scientific collaboration and its changing patterns
have been extensively studied from sociological and
bibliometric standpoints, as well as in studies of research
policy and research ethics (Beaver, 2001
; Birnholtz, 2006;
Chompalov
et al., 2002; Cronin, 2012; Glänzel and Schubert,
2004; Harsanyi, 1993; Katz and Hicks, 1997; Leyesdorff and
Wagner, 2008; Marshakova-Shaikevich, 2006; Wagner et al.,
2001; Wuchty et al., 2007; among others). It has been
observed that in broader disciplines such as sciences, there is a
trend towards increasing collaboration in general (Glänzel,
2002) and international collaboration in particular (Wagner
and Leydesdorff, 2005).
The growth of scientific collaboration has now become an area
of interest to researchers to the point that it was the topic of a
conference held at the University of Valencia (Spain) in
November 2013 (González Alcaide
et al., 2013). An
international network, the aim of which is to facilitate
collaboration in scientometrics, infometrics and webometrics,
should also be mentioned here: it is the COLLNET network
,
which has organised an annual international meeting since the
year 2000.
Scientists are members not only of local and national, but also
international scientific communities (Crane, 1972
; de Solla
Price, 1986; Schott, 1991). These different levels of
collaboration are sometimes difficult to evaluate since many
factors have to be taken into account, i.e., it is not always easy
to decide what is collaboration and what is not (Katz and
Martin, 1997; Laudel, 2002). Fortunately this difficulty has
not prevented many authors from trying to measure
collaboration, mainly international collaboration, by using co-
authorship networks as the standard way to reach comparable
numerical results (Glänzel, 2002
; Glänzel and Schubert, 2004;
Wagner and Leyesdorff, 2005
, to name just a few).
With the exception of a few studies which considered that the
different types of collaboration were not exclusive (for
example, Bordons Gangas
et al., 2013), the vast majority of
studies have considered them from an exclusive standpoint by
measuring the different levels of collaboration separately (e.g.
Leimu and Koricheva, 2005
; Sin, 2011) without taking into
account the fact that in global and multidisciplinary sciences
they usually occur simultaneously. This is the case for
astrophysics, a discipline with a dual nature in the sense that it
combines astronomy, an observational science related to the
description and the classification of the universe, and physics,
which is concerned with the basic properties of celestial
objects (Pedersen, 1993
). Moreover, physics not only
incorporates theory and practice (Newman, 2004
), but also
separate branches of expertise, each one with its own
characteristics: high-energy physics, particle physics,
relativistic physics, solid-state physics, biology, chemistry,
aerospace, electrical and mechanical engineering,
mathematics, etc. This is why we think that astrophysics is the
perfect touchstone to sketch an overall picture of the complex
collaboration scenarios involved in scientific research. An
inclusive study may also help find the most noteworthy issues
so as to modify collaboration practices (if required or desired)
within the scope of research management and policy.
To sum up, although the literature on collaboration has
generally paid great attention to detail, it seems that the
following global question has been left unaddressed (1): is it
possible to compare numerically and simultaneously the
different levels of collaboration in a given corpus of research
papers, or even in a single research paper? In order to answer
this question, it is necessary to look at the issue from a less
detailed point of view, i.e., to approach it from a more global
standpoint that does not focus specifically on collaboration
networks or links between researchers. In our opinion, what is
needed is the establishment of different indicators that may
allow a simultaneous measure of the main types of
collaboration (international, national and local) in any given
corpus. The referred indicators are introduced in the methods
section.
After computing simultaneously the different types of
collaboration, further interesting questions such as these may
be addressed:
(2) Are there any time variations in collaboration patterns in
astrophysics as already reported in other fields?
(3) Do collaboration patterns depend on the scope of the
journals selected for our corpus?
(4) What conditions (economic, social, etc.) are responsible for
the variations in collaboration patterns, if any?
The best approach to answering these questions is the analysis
of different time periods and journals.
Methods
First, we recorded the different countries, cities and
institutions mentioned in the bylines of all the research papers
included in our corpus. The numerical indicators that we
propose to measure the different types of collaboration
(international, national and local) in our whole corpus or in a
single research paper are as follows:
International collaboration is studied in terms of the
mean number of countries per research paper.
National collaboration is studied in terms of the mean
number of cities per each country. The numerical
indicator refers to the mean quotient between the
number of cities and the number of countries per
research paper, i.e., it corresponds to the average of the
individual national collaboration index for every country
included in the bylines of each research paper.
Local collaboration is studied in terms of the mean
number of institutions per city. The numerical indicator
refers to the mean quotient between the number of
institutions and the number of cities per research paper,
i.e., it corresponds to the average of the individual local
collaboration index for every city included in the bylines
of each research paper.
A clarification is in order here: whenever a given country, city
or institution is indicated more than once in the bylines of a
single research paper, we counted them as a unique item; by
contrast, whenever the same country, city or institution is
indicated in the bylines of different research papers, we
counted them as different items. The very definition of any of
the three numerical indicators implies that a value of '1'
corresponds to the absence of collaboration (international,
national and local). The way of computing our collaboration
indicators leads to two further research questions:
(5) Are the proposed numerical indicators affected by authors'
mobility?
(6) Are the proposed numerical indicators affected by intra-
national collaboration, i.e., collaboration among given
institutions with different branches located in different cities
of the same country?
To answer both questions, it is necessary to separately study
the different types of mobility (international, national and
local) together with intra-national collaboration. International
mobility refers to authors working in different countries at the
same time, national mobility to authors working in different
cities in the same country and local mobility to authors
working at different institutions, mainly universities, in the
same city. Since it may happen that on some occasions
researchers only list an affiliation with the host institution, our
mobility data must be considered as lower estimates of the
actual values. Another level of collaboration that is also worth
studying refers to intra-institutional collaboration, i.e.,
collaboration among different departments in the same
institution.
Moreover, although the three proposed numerical indicators
are always sample-affected, it is worth stressing that national
and local collaboration indicators are doubly affected by the
sample. While the international collaboration indicator only
considers a single variable (the number of countries per
research paper), the national and local collaboration
indicators include two different variables (the number of cities
divided by the number of countries per research paper in the
case of national collaboration, and the number of institutions
divided by the number of cities per research paper in the case
of local collaboration).
Finally, so as to determine whether the paired two-sample
differences observed are statistically significant or not, we
analysed our data by means of the student's t-test. The alpha
value has been set at 0.05.
The corpus
Journal citation impact and prestige were taken into account
in the journal selection process. The study incorporated three
selection criteria: journals must (1) have the highest impact
factors; (2) publish papers on observational data and/or
theoretical analyses; (3) be freely accessible online. Four
journals were found to meet the three criteria and were
selected for this study: two European journals, Astronomy
and Astrophysics and Monthly Notices of the Royal
Astronomical Society (RAS); and two US-based journals, The
Astronomical Journal and The Astrophysical Journal.
Astronomy and Astrophysics (impact factor: 5.084) publishes
papers on theoretical, observational, and instrumental
astronomy and astrophysics, and is published by Édition
Diffusion Presse (EDP) Sciences. Monthly Notices of the RAS
(impact factor: 5.521) covers research on astronomy and
astrophysics. This journal is published on behalf of the Royal
Astronomical Society and is often preferred by astronomers
from the United Kingdom and the Commonwealth. The
Astronomical Journal (impact factor: 4.965) publishes papers
on astronomical research, while The Astrophysical Journal
(impact factor: 6.733) has a more global focus and publishes
papers in astronomy and astrophysics. Both journals are
published on behalf of the American Astronomical Society. All