Tree Inheritance Distance

Tree comparison is an important method in various areas. In order to compare class hierarchy in object-oriented languages, there is a need to compare trees in the context of the hierarchy changes. This paper addresses tree dissimilarity based on two measures. First, changes in edges between nodes and parents are measured by introducing Edge Edit Distance (EED). Second, changes in inheritance relationships between nodes are measured by introducing Tree Inheritance Distance (TID). It is shown that EED and TID increase with the dissimilarity in the class hierarchies of the compared program versions.