Similarity Measures, Author Cocitation Analysis, and Information Theory, JASIST (forthcoming)

Loet Leydesdorff loet at LEYDESDORFF.NET
Mon Apr 12 15:12:00 EDT 2004

The preprint version is now available at

The use of Pearson's correlation coefficient in Author Cocitation
Analysis was compared with Salton's cosine measure in a number of recent
contributions. Unlike the Pearson correlation, the cosine is insensitive
to the number of zeros. However, one has the option of applying a
logarithmic transformation in correlation analysis. Information calculus
is based on both the logarithmic transformation and provides a
non-parametric statistics. Using this methodology one can cluster a
document set in a precise way and express the differences in terms of
bits of information. The algorithm is explained and used on the data set
which was made the subject of this discussion.


Loet Leydesdorff
Amsterdam School of Communications Research (ASCoR)
Kloveniersburgwal 48, 1012 CX Amsterdam
Tel.: +31-20- 525 6598; fax: +31-20- 525 3681
 <mailto:loet at> loet at ;

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