Measure: Depth of Inheritance Tree

A.Definition Node: A class in the inheritance tree Root Node: A node with no parents. Leaf Node: A node with no children. Edge: An edge connects one node to another. In an OO context, it denotes the inheritance of the super class by the subclass. Path: The traversal from one node to another node. Depth: The longest path (the greatest number of edges) from the root node to a leaf node.

B.Entities, Attributes and Their Relationships A1. Entity The entity is the inheritance tree.

A2. Attributes An attribute of the inheritance tree is its depth.

A3. The relationship An inheritance tree must have a root node. This implies that an inheritance tree must have at least one node. Thus, every inheritance tree has a depth (See definition).

C.Units and Scale Types and Their Relationships B1. Units The unit is the edge between two nodes. Note: Another unit could be a node, if the definition of depth was changed to greatest number of nodes from the root node to a leaf node, including both the root and leaf node.

B2. Scale Types The scale type is a ratio scale because there is an absolute zero and the ratios between two or more inheritance trees are preserved.

B3. The Relationship An edge is a ratio scale unit of depth.

D. Values The value is the count of edges in the longest path from the root node to a leaf node. The value applies to the inheritance tree. It measures the depth of the inheritance tree and the unit is in number of edges.

E. Properties of Values The permissible values are non-negative integers. The set of permissible values is infinite, unbounded and discrete.

F. Measurement Instrument The measurement instrument is counting the number of edges for the longest path from the root to a leaf node.