Zhao DZ "Towards all-author co-citation analysis " Information Processing & Management 42(6):1578-1591, December 2006

[Eugene Garfield]

Dangzhi Zhao : E-mail Addresses: dzhao at ualberta.ca  


Title: Towards all-author co-citation analysis 

Author(s): Zhao DZ 

Source: INFORMATION PROCESSING & MANAGEMENT 42 (6): 1578-1591 DEC 2006 

Document Type: Article 
Language: English 
Cited References: 17      Times Cited: 0      

Abstract: 
The present study examines one of the fundamental aspects of author co-
citation analysis (ACA): the way co-citation counts are defined. Co-
citation counting provides the data on which all subsequent statistical 
analyses and mappings are based, and we compare ACA results based on two 
different types of co-citation counting: on the one hand, the traditional 
type that only counts the first one among a cited work's authors, and on 
the other hand, a simplified approach to all-author co-citation counting 
that takes into account the first five authors of a cited work. Results 
indicate that the picture produced through this simplified all-author co-
citation counting contains author groups that are more coherent, and is 
therefore considerably clearer. However, this picture represents fewer 
specialties in the research field being studied than that produced through 
the traditional first-author co-citation counting when the same number of 
top-ranked authors is selected and analyzed. Reasons for these effects are 
discussed. Variations of counting more than first authors are compared. 
(c) 2006 Elsevier Ltd. All rights reserved. 


EXCERPT FROM PAPER :
'CONCLUSION:
We have examined one of the fundamental aspects of author co-citation 
analysis (ACA) that has rarely been touched since its introduction in 
1981, how the way that the co-citation counts are defined which provide 
the raw data on which all subsequent statistical analyses and mappings are 
based.  

A comparison between first-author and all-author co-citation analyses of 
the XML research field has indicated that an all-author co-citation 
analysis, which takes into account more links between related authors, 
results in a considerably clearer picture of the intellectual structure of 
a research field than the classic first-author co-citation analysis.  
Although the same number of authors selected by citedness when counting 
all authors tends to represent fewer specialties than counting only first 
authors, this should not be a problem if future studies can confirm that 
including a larger number of authors in the analysis will increase the 
number of specialties identified.  Some techniques and software programs 
such as Pathfinder networks (PFNETs) certainly would allow this.  For 
example, it has been reported that PFNETs when applied to ACA allow about 
200 author names to be apped, and that they have shown considerable 
advantages for ACA (White, 2003).

When counting all authors in ACA studies, the question of how to define co-
citation needs to be answered.  If we simply modify the traditional 
definition by defining an author's oeuvre as all works with this author as 
one rather than as the first of the authors of each of these works, two 
authors could also be considered as being co-cited when a paper co-
authored by them is cited.  We have presented a preliminary comparison 
between the ACA results from this inclusive way of counting all-author co-
citations and those from excluding cited co-authorship from co-citation 
counts.  The result was in favor of exclusive co-citation counts in the 
study of intellectual structures on the one hand, but it revealed the 
potential of inclusive co-citation counts in the study of social 
relationships in ACA on the other.

ACA has been shown to be a powerful approach to the study of scholarly 
communication.  However, since collecting co-citation counts in the print 
world is nearly impossible without the aid of citation indexes, ACA 
studies have been relying heavily on the ISI databases, and consequently 
have been limited to first-author co-citation.  As full-text scholarly 
publications and tools for searching them are becoming increasingly 
available on the Web, there are now alternatives to the ISI databases for 
collecting co-citation data, allowing us to go beyond first-author co-
citation towards all-author co-citation.  As the present study shows by 
example, this provides us with a clearer picture of scholarly 
communication patterns, and with a way to exploit the full potential of 
ACA in the study of both intellectual structures of research fields and 
social relationships of scholarly communities.  We are confident that 
future ACA studies will take advantage of emerging data sources and tools, 
and will combine recent advanced information visualization techniques with 
various co-citation counting methods to produce even more interesting and 
revealing ACA results."

Author Keywords: author co-citation analysis; scholarly communication; 
citation analysis; web publishing 
KeyWords Plus: SCIENCE; PUBLICATIONS; WEB 

Addresses: Zhao DZ (reprint author), Univ Alberta, Sch Lib & Informat 
Studies, Edmonton, AB T6G 2J4 Canada
Univ Alberta, Sch Lib & Informat Studies, Edmonton, AB T6G 2J4 Canada 

E-mail Addresses: dzhao at ualberta.ca, dzhao at ualberta.ca 

Publisher: PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, 
KIDLINGTON, OXFORD OX5 1GB, ENGLAND 
Subject Category: COMPUTER SCIENCE, INFORMATION SYSTEMS; INFORMATION 
SCIENCE & LIBRARY SCIENCE 
IDS Number: 062TI 
ISSN: 0306-4573 

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