Guidelines for Reorganizing the Ontology

This set of guidelines is the least developed of all.

In order to reorganize or purify a part of the ontology:

1. Do it slot by slot in an entire subtree. For example, look for improper uses of a particular case role in the entire region.
2. Make any change at the highest level possible in the tree.
3. If most nodes in a subtree require a slot but some do not, add the slot at the highest level possible and use *nothing* at the few places where the slot should be blocked from being inherited.
4. In reorganizing overly large fanouts (10 children or more), look for at least one distinguishing yet general characteristic among those children and create a parent node that would best describe that characteristic.
5. When reorganizing fanouts, try to leave as few children as possible remaining outside of the newly-created fanouts.

We also reorganize so that we strengthen the depth of the ontology instead of expanding the breadth. Another good reason to reorganize is to facilitate ontology browsing--having smaller subtrees makes it easier to browse, at least in this version of our tool. Of course, it would be better to anticipate new subtrees before they become "overgrown," but that is not always possible considering the rapid growth and constant changes happening in the ontology.

Additional Guidelines:

1. Find a parent node that has 9 or more children. Because so many children make such a concept-cluster unwieldy, this kind of parent node is often a good candidate for reorganizing.

2. Usually a good way to examine the cluster is to list all children under the parent--preferably on paper.

3. More often than not, some of the chidlren share some common feature, at a fairly high and general level (one hopes!). Once the feature has been determined, it helps to name the new parent node in a way consistent with the naming guidelines as well as the organization of the ontology.

4. It should not be difficult to find parent nodes for the remaining children, if the shared common features are general enough. It is good policy to not allow children to "hang out" of these clusters. In other words, try to find general enough parents for all children, if possible.