The point of it…
is to see where the key words are distributed within the text. Do they cluster around the middle or near the beginning of the text?
How it's done
This will calculate the inter-relationships between all the key words identified so far, excluding any which you have deleted or zapped.
1.it does a concordance on the text finding all occurrences of each key word;
2.it then works out which of each of the other key words appear within the collocation horizons (set in Settings). It uses the larger of the two horizons.
3.it then plots all the words showing where each occurrence comes in the original file (with a "ruler" showing how many words there are in each part of the file).
4.it computes how many other key-words co-occurred with it, within the current collocational span.
5.it computes a plot dispersion value.
Note: this process depends on KeyWords being able to find the source texts which your original word-list was based on.