Diagonal Values in ACA

Diagonal Values in ACA

Sean Eom (Southeast Missouri State University, USA)
DOI: 10.4018/978-1-59904-738-6.ch004
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Abstract

Diagonal values in the cocitation frequency counts matrix are a fundamental issue in ACA study. Diagonal values are the co-citation frequency counts between the author himself/herself excluding self-citation. Retrieving exact values of diagonal values in the co-citation matrix requires a manual and time consuming procedure. For that reasons, ACA researchers suggested many different approaches to create, not retrieving the real values, the diagonal cells in the cocitation matrix. They include the mean cocitation count, missing values, zeroes, highest off-diagonal counts, adjusted off-diagonal values, and the number of times cocited with himself/herself. The majority of ACA researchers seem to prefer to use either the adjusted value approach by adding three highest off-diagonal values and divided by two or the missing value approach. This chapter empirically examines the impact of these different approaches on the ACA outcomes. Based on the results of this study, if the pure cocitation counts are not used, the next best alternatives are as follows. They are the missing value approaches, mean cocitation value approach, and the highest off-diagonal value approaches in the order of the highest total variance explained.
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Number Of Times Cocited With Himself/Herself

A possible solution for the diagonal value problem is suggested by Ahlgren, Jarneving, and Rousseau (2003, p.551.) and White (Howard D. White, 2003). The diagonal values should be the number of articles in the bibliographic database that cite at least two (different) works authored or coauthored by the person. Ahlgren, Jarneving, and Rousseau suggest excluding self-citations. This number is very difficult to get when using ISI databases. The custom database and cocitation matrix generation system we have developed allowed us to retrieve the numbers so we can yield a co-citation frequency matrix, which Ahlgren, Jarneving, and Rousseau describe as “a mathematically complete matrix.” One solution for the diagonal value problem is suggested by Ahlgren, Jarneving, and Rousseau (2003, p.551.)

We think that perhaps the best solution for the “diagonal” problem (if such solution is deemed necessary) is to use the number of times for an author, say AU, has been cocited with himself (excluding self-citations). This is the number of articles in the pool under study that cite at least two (different) works (co)authored by AU. Such a method would yield a mathematically complete matrix, which is always easier to study (statistically) than an incomplete one (Fienberg, 1980). Our suggestion is inspired by Eom and Faris (Eom & Farris, 1996), who, however, use the number of times an author is cocited with him/herself as a way to determine the author set to be analyzed.

White (2003, p.1253) also discussed the issue of diagonal values in the cocitation matrix (Howard D. White, 2003). He believes that “the most meaningful entry would be a count of the publications in which two or more of the author’s works are jointly cited.”

Complete Chapter List

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Table of Contents
Acknowledgment
Sean B. Eom
Chapter 1
Sean Eom
Author cocitation analysis (ACA) is a branch of bibliometrics. Bibliometrics/informetrics is one of the older areas of library and information... Sample PDF
An Introduction to Bibliometrics and Informetrics
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Chapter 2
Sean Eom
This chapter introduces online citation data retrieval using the Web of Science and Dialog Classic. The Web of Science provides access to... Sample PDF
An Introduction to Online Data Retrieval and Issues
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Chapter 3
Sean Eom
Virtually all ACA studies using Thomson’s ISI citation indexes used only the first author to retrieve the cocitation counts. Therefore, this has... Sample PDF
The Impact of the ISI Convention of Relying on only the Name of the First Author on ACA Results: An Empirical Investigation
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Chapter 4
Diagonal Values in ACA  (pages 91-121)
Sean Eom
Diagonal values in the cocitation frequency counts matrix are a fundamental issue in ACA study. Diagonal values are the co-citation frequency counts... Sample PDF
Diagonal Values in ACA
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Chapter 5
The Fox-Base Approach  (pages 123-136)
Sean Eom
Chapter II introduced online cocitation counts retrieval using Dialog Classic and citation index files. Certainly Dialog Classic is an attractive... Sample PDF
The Fox-Base Approach
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Chapter 6
Sean Eom
This chapter shows another alternative approach of building citation database and retrieval system using the spreadsheet program, Microsoft Excel.... Sample PDF
Building Databases and the Cocitation Counts Generation System Using Microsoft Excel Program in Visual Basics
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Chapter 7
Sean Eom
The previous two chapters examined the two alternative approaches of retrieving cocitation counts using custom databases and cocitation frequency... Sample PDF
Overview of Author Cocitation Analysis Procedures
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Chapter 8
Sean Eom
This chapter describes the factor procedure. The first section of the chapter begins with the definition of factor analysis. This is the statistical... Sample PDF
Principal Component Analysis Using the Factor Procedure
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Chapter 9
Sean Eom
This chapter describes the distance and cluster procedure of the SAS system. SAS version 9 introduced the proc distance procedure. All previous... Sample PDF
The Distance and Cluster Procedure
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Chapter 10
Multidimensional Scaling  (pages 225-254)
Sean Eom
This chapter discusses multidimensional scaling (MDS) procedures. MDS is a class of multivariate statistical techniques/procedures to produce two or... Sample PDF
Multidimensional Scaling
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Chapter 11
Sean Eom
This chapter briefly introduces the use of SPSS version 15.0 to conduct ACA analysis. The SPSS accepts datafiles in many different formats including... Sample PDF
ACA Analysis with the 15.0.0 Verison of SPSS for Windows
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Chapter 12
Sean Eom
This is the capstone chapter that shows how the concepts, tools, and techniques discussed in each of the previous chapters can be applied in... Sample PDF
The Intellectual Structure of Decision Support Systems Research (1969-1989)
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Chapter 13
Sean Eom
This chapter extends an earlier benchmark study (Sean B. Eom, 1995) which examined the intellectual structure, major themes, and reference... Sample PDF
The Changing Structure of Decision Support Systems Research: An Empirical Investigation through Author Cocitation Mapping (1990-1999)
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