Elementary and composite metrics
Some of our metrics will be elementary and some composite. An elementary metric is measured directly from the product or a project record:
An example of elementary product metric is the number of source lines. An example of elementary process metric is the number of incremental compilations of a system.
Elementary metrics are provided by default by the metric tool. There is no means to remove them or to define new ones since they are not expressed as a combination of other metrics.
From these elementary metrics we may define composite ones:A later section will introduce a number of operations for defining composite metrics out of elementary ones. Again we may distinguish between product and process:
By convention, this definition treats as process metric as a composite metric involving both product and process components.
The classification introduced for metrics extends to measures, so that we may talk about an elementary product measure, a composite process measure and so on.