In this position paper we discuss a number of issues relating to model metrics, with particular emphasis on metrics for UML
models. Our discussion is presented as a series of nine observations where we examine some of the existing work on applying
metrics to UML models, present some of our own work in this area, and specify some topics for future research that we regard
as important. Furthermore, we identify three categories of challeges for model metrics and describe how our nine observations
can be partitioned into these categories.
Keywords software metrics - object-oriented systems - UML - metamodels