Among several alternative viewpoints for building software quality metrics, evaluating the consistency between different models
in a software specification or implementation appears to be fruitful.
An obvious difficulty is that different models are usually expressed
by means of different concepts, and then, confronting heterogeneous
representations is not straightforward.
In this paper, we propose a solution for measuring the
consistency between the architecture and the communication models.
After some sensible transformations, the information about both
models are captured trough hierarchical representations. We define
and discuss a similarity measure between hierarchies, that eventually
founds the software metric we propose. Lastly, we investigate how to
scale and interpret the metric values and give an application example
with SDL.