Figure 15. Frequency of occurrence of words appearing among the 20 highest scoring marker words for Shakespeare, resulting from a 10 fold cross validation.

This process involved the removal of 10% of plays by Shakespeare (3), and 10% of plays by other authors (14). The 20 highest (left) and lowest (right) scoring marker words were calculated for every possible triplet of removed plays by Shakespeare ( combinations), and for each, a random selection of 14 plays by other authors. The marker words determined across the full text corpus are highlighted in green. This demonstrates this selection of words as valid for classification, and that the CM_–1 score is robust against the removal and addition of plays.