We measure the efficacy of a software process indirectly.
That is, we derive a set of metrics based on the outcomes
that can be derived from the process.
Outcomes include
measures of errors uncovered before release of the software
defects delivered to and reported by end-users
work products delivered (productivity)
human effort expended
calendar time expended
schedule conformance
other measures.
We also derive process metrics by measuring the
characteristics of specific software engineering tasks.