The validity of Bradford’s Law in academic electronic mailing lists

Date02 November 2015
Pages1031-1046
DOIhttps://doi.org/10.1108/EL-06-2014-0087
Publication Date02 November 2015
AuthorCristina Faba-Pérez,Ana-María Cordero-González
SubjectInformation & knowledge management,Information & communications technology,Internet
The validity of Bradford’s Law
in academic electronic
mailing lists
Cristina Faba-Pérez and Ana-María Cordero-González
Department of Information and Communication,
University of Extremadura, Badajoz, Spain
Abstract
Purpose – The purpose of this paper was to check the validity of Bradford’s Law in the contemporary
world of academic electronic mailing lists.
Design/methodology/approach – The present research study applied Bradford’s Law to academic
electronic mailing lists to determine: whether, on the Internet, mailing lists and the posts sent to them
follow the same distribution as scientic journals and the articles published in them with respect to the
original form of Bradford’s Law; and whether the behaviour of the Bradford distributions differs
depending on the type of academic discipline (social studies or sciences) and subject category
(documentation and education, medicine and life sciences) to which the list belongs. As a prior step, the
utility of mailing lists was analysed during the 10-year period of 2002-2011, together with their expected
future in terms of ratifying the applicability of the Law.
Findings – The results showed that, in general, electronic mailing lists are continuing to be used, and
that Bradford’s Law is indeed satised, especially in the science subject categories, coherent with the
fact that Bradford’s Law in cybermetrics holds only for fairly narrow (closed) and well-dened
(homogeneous) environments.
Originality/value – The originality of the present research study was to check the validity of the
historic Bradford’s Law in the contemporary world of Internet.
Keywords Life sciences, Education, Documentation, Medicine, Bradford’s Law,
Electronic mailing lists
Paper type Research paper
Introduction
Bradford’s Law of scattering, referring to scientic literature, was originally enunciated
by Samuel C. Bradford in the following terms:
If scientic journals are arranged in order of decreasing productivity of articles on a given
subject, they may be divided into a nucleus of periodicals more particularly devoted to the
subject and several groups or zones containing the same number of articles as the nucleus,
when the numbers of periodicals in the nucleus and succeeding zones will be as 1:n:n
2
.
(Bradford, 1934, pp. 85-86)
With this statement of the law, Bradford was expressing the observed highly uneven
distribution in journals’ output of articles. In particular, most articles are concentrated in
just a few journals, and there is a small proportion published in a large number of
The present work was nanced by the Consejería de Empleo, Empresa e Innovación of the Junta
de Extremadura and the Fondo Social Europeo as part of the Aid to Research Groups GR10019.
The current issue and full text archive of this journal is available on Emerald Insight at:
www.emeraldinsight.com/0264-0473.htm
Validity of
Bradford’s
Law
1031
Received 5 June 2014
Revised 18 September 2014
Accepted 13 October 2014
TheElectronic Library
Vol.33 No. 6, 2015
pp.1031-1046
©Emerald Group Publishing Limited
0264-0473
DOI 10.1108/EL-06-2014-0087
journals (Castillo and Carretón, 2010). This is why most articles on a given topic can be
searched for in just a small number of journals (the nucleus or core). After this core, a
much greater number of journals will have to be searched to retrieve the same number of
articles. This greater number will constitute the rst zone, and so on, with the rest of the
zones. The number of zones to determine is arbitrary, although Bradford originally
dened three (Morato Lara, 1999).
To display Bradford distributions, one uses a semi-logarithmic plot. This will
comprise two curved segments – initial (core) and nal (Zone 2) – and an intermediate
straight-line segment (Zone 1). The number of journals that form the core of the
distribution is read off of the x-axis, corresponding to the point at which the initial
curved segment makes the transition to the straight-line segment (Egghe and Rousseau,
1990;Ferreiro, 1993)(Figure 1).
Despite its acceptance by the international scientic community, Bradford’s Law
takes no account of certain variables – for example the journals’ publication frequency
(Urbizagástegui, 1996) and size (Bensman, 2001) – so that the law identies the journals
that are the most productive but not necessarily the most specialized in the eld under
study. These reasons have led to various interpretations of the theoretical basis of the
law. Gorbea-Portal (1996) used the mathematical model of Bradford, identifying the
regularity of the concentration and dispersion of knowledge recorded by sources.
Oluic-Vukovic (1997) studied the classical bibliometric law and the more general
stochastic models. Basu (1998) discussed the theoretical aspects of Bradford’s Law and
its graphical representation, while Chongde and Zhe (1998) indicated the need for more
statistical tests of new models of Bradford’s Law to obtain the best model. Hjørland and
Nicolaisen (2005) indicated that the meaning of subject has never been explicitly
addressed in relation to Bradford’s Law. They introduced the distinction between lexical
scattering, semantic scattering and subject scattering.
In stating the law, Bradford focused exclusively on the documental aspect of
scientic journals and the articles they publish. There have been numerous studies that
have followed this pattern in applying Bradford’s Law to the eld of scientic journals
(Bigdeli and Gazni, 2012;Kademani et al., 2013;de Arenas et al., 2002;Pereira et al., 2007;
Singh et al., 2007) and the development of library collections through citation analysis
that identies the most frequently cited scientic journals and, therefore, those
Figure 1.
Typical Bradford
curve
EL
33,6
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