www.tlab.it
Correspondence
Analysis
Correspondence Analysis is a factorial
analysis technique applied to the study of data tables whose cells contain either frequency
values (real positive numbers) or presenceabsence values ("1" or
"0").
Like all factorial analysis techniques, correspondence
analysis allows the extraction of new variables  the factors  with the property of summarizing in a
organized way the significant information contained in the
countless data tables cells; furthermore, this analysis technique
allows the creation of graphs showing  in one or more spaces  the
points that detect the objects in rows
and columns, that is  in our case  the linguistic entities
(words, lemmas, texts segments and texts) with the respective
source features.
In geometrical terms, each factor sets up a spatial
dimension  that can be represented as an axis line  whose center
(or barycentre) is the value "0", and that develops in a bipolar
way towards the negative () and positive (+) end, so that the
objects put on opposite poles are the most different, almost like
the "left" wing and the "right" wing on the political axes.
In TLAB
the analysis results are summarized through graphs that allow the
evaluation of the relationships of proximity/distance  or rather
similarity/dissimilarity  between the considered objects.
Furthermore, TLAB shows measures (i.e. Absolute Contributions and Test Value) that help to understand the poles of factors that set up
similarities/dissimilarities between the considered objects.
