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T-LAB
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Dictionary Building
Co-occurrence Analysis
Word Associations
Co-Word Analysis and Concept Mapping
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Concordances
Co-occurrence Toolkit
Thematic Analysis
Thematic Analysis of Elementary Contexts
Modeling of Emerging Themes
Thematic Document Classification
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Texts and Discourses as Dynamic Systems
Comparative Analysis
Specificity Analysis
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Glossary
Analysis Unit
Association Indexes
Chi-Square
Cluster Analysis
Coding
Context Unit
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Correspondence Analysis
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Disambiguation
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Elementary Context
Frequency Threshold
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IDnumber
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Normalization
Occurrences and Co-occurrences
Poles of Factors
Primary Document
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Specificity
Stop Word List
Test Value
Thematic Nucleus
TF-IDF
Variables and Categories
Words and Lemmas
Bibliography
www.tlab.it

Association Indexes


In T-LAB the association indexes (or similarity coefficients) are used to analyse the co-occurrences of the lexical units (LU) inside the elementary contexts (EC), that is to analyse binary data of the presence/absence type.

For instance, given two LU and ten EC, we can obtain the following example:

 

 

 

The same data can be represented in the following way:

 

 

Generalizing and using the letters of the alphabet:

 

 

The formulas corresponding to the six association indexes used by T-LAB are the following:

 

If, for example, we have calculated association coefficients of co-occurrence relationships concerning ten LU, we can obtain a table like the following:

 

In effect T-LAB produces and analyses analogous tables of N x N dimensions (where N can correspond to hundreds of columns), both using Multidimensional Scaling and Cluster Analysis.

Similar tables are also used to calculate second order similarities between pairs of keywords (see the Word Associations tool).