Designer enables you to create multi-level hierarchical classification trees by means of base classes and derived classes. Base classes constitute the highest level of a classification tree. Derived classes are specializations of base classes.
When you create a class hierarchy, consider the following suggestions.
- Create derived classes as a true specialization of their parent class.
- Disjoint classes that compete with each other.
- Classes that compete with each other should be based on a similar level of abstraction.
- A working classification tree must contain at least two classes.
- Do not reuse the name of a deleted, learned document class in the same project. Doing so may cause inconsistencies within the project. When you create a document class, BIC creates a directory with the name of the document class that contains the learnset documents for this class. This directory remains when you delete the class from the class hierarchy. If you create a new class with this name, it appears as if learnset documents are available when they are not.
Example
A classification tree as shown below does not yield satisfactory results.
Such a classification tree is insufficient because the Invoices class includes two derived classes that are not parallel, Invoices from Travel Agencies and Invoices November 2015. It is conceivable that Invoices November 2015 would also include invoices that came from travel agencies and therefore would be part of the Travel Agencies class.
A better classification tree might consist of Invoices from Travel Agencies and Invoices from Mechanics, or Invoices November 2015 and Invoices December 2015.