Evoke Rules

Evoke rules are very useful for adding new associations to existing input. Based on the content that it is searching, the clustering engine may sometimes appear to overlook larger concepts and focus instead on smaller groups. For example, when searching for "pittsburgh" on the web, you will often end up with clusters for the "Pittsburgh Pirates", "Pittsburgh Penguins", "Pittsburgh Steelers", "Pittsburgh Panthers", and "Pittsburgh Riverhounds" (all local sports teams). Unfortunately, none of these web documents actually tell you that these are sports teams. Such customizations are not usually necessary but can be used to tailor your results. Adding this knowledge is simple:

<evoke new="Sports Teams" when="Pittsburgh Pirates" />
<evoke new="Sports Teams" when="Pittsburgh Penguins" />
<evoke new="Sports Teams" when="Pittsburgh Steelers" />
<evoke new="Sports Teams" when="Pittsburgh Panthers" />
<evoke new="Sports Teams" when="Pittsburgh Riverhounds" />

Evoke rules are specified with an evoke element in XML (as shown in the previous example), or (more commonly) in the Watson™ Explorer Engine administration tool.

In the Watson Explorer Engine administration tool, you enter the word or phrase that you want to evoke another ("Pittsburgh Pirates", "Pittsburgh Penguins", and so on from the previous example) and then associate it with new or existing categories. To do this, enter the word or phrase in the Knowledge Bases >> Entry List form, press return, and change the treatment of that word or phrase to evokes a category. After selecting this option, the right side of the screen enables you identify to one or more categories that are all evoked from this word. The weight allows you to make certain categories much more important. Greater weights emphasize associated categories, a weight of zero disables a category, and a negative weight disassociates the word or phrase from that category.