"This preliminary experiment indicates ":

"that programmers more effectively debug and modify classes at or near the root of the class hierarchy than classes deep in the class hierarchy. The results of this experiment also appear to indicate that there is a point of accumulated complexity where the relative class size and loss of data abstraction make the task of comprehending a single class at the root as difficult as searching through the inheritance tree.

Our results suggest that the depth of the inheritance tree does affect programming tasks. However, more studies will need to be done to determine if there is a depth threshold for programming tasks and the trade-offs between depth and breadth of the inheritance tree."