Basili and Rombach
[Basili-88] define a Goal/Question/Metric
paradigm
that provides an excellent mechanism for defining a goal-based measurement
program. Figure 3 illustrates the Goal/Question/Metric paradigm.
The second
step in setting up a metrics program
is to select one or more
measurable goals. The goals
we select to use in the Goal/Question/Metric will vary depending on the level we are considering
for our metrics. At the organizational
level, we typically examine high-level strategic goals like being
the low cost provider, maintaining
a high level of
customer
satisfaction, or meeting projected
revenue or profit margin
target. At the project level, we
typically look at goals that emphasize project
management and control
issues or project level requirements and objectives.
These goals typically reflect
the project success factors like on time delivery, finishing the project within budget
or delivering software with the required level of quality or performance. At the
specific
task level, we consider goals
that emphasize task success factors. Many times these are expressed in terms of the
entry and exit criteria for the task.
Software metrics programs must be
designed
to provide the specific information necessary
to manage software projects and
improve software engineering processes and services. Organizational, project, and task goals are determined in
advance and then metrics are selected
based on those goals. The metrics
are used to determine our
effectiveness in meeting these goals.
When talking
to our customers, we may find many of their individual needs are
related to the same goal
or problem but expressed from their perspective or in the terminology of their specialty. Many times,
what we hear is their frustrations.
For example, the Project Manager may need
to improve the way project schedules are estimated.
The Functional Manager
is worried about late
deliveries. The practitioners complain
about overtime and not having
enough time to do things
correctly. The Test Manager states that by the time the test group
gets the software it’s too late to test it
completely before shipment.
When selecting
metrics, we need to listen to these customers and, where possible, consolidate their various goals or problems
into statements that will help
define the metrics that are needed
by our organization or team.
