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).