What is a Metric?
We distinguish between measure and metric. To clarify, let’s start by defining what is meant by measure and by
metric.
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Measure: a raw data item that is directly measured and that will be used to calculate a
metric.
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Metric: an interpretation of a measure or a set of measures that you use to guide your
project.
For example, recording how many test cases have passed and how many have failed are measures.
Interpreting what level of quality this indicates and how it reflects the team's progress within the current iteration
is a metric.
Why Measure?
Measurements will mainly help you to:
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Communicate effectively. Measurement supports effective communication among team members and
project stakeholders.
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Identify and correct problems early. Measurement enables you to identify and manage potential
problems early in the development lifecycle.
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Make informed trade-offs. Measurement helps assess objectively the impact of decisions,
helping managers to make trade-off decisions to best meet project goals.
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Tune estimations. Recording schedule, progress, and expenditures for projects will help team
members to make more reliable estimations in the future.
Potential Challenges
There are several dangers when it comes to metrics:
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They can be too costly. The benefit provided by the metric must exceed the cost of collecting
it. Keep your measurements simple and easy to collect.
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They’re a poor substitute for communication. The best way to determine the current status of a project
is to ask the people involved, not to look at a report summarizing key metrics.
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They can be misleading. No metric or collection of metrics is perfect. Furthermore, the
measurements upon which they are based can be manipulated by the people capturing them. Don’t rely
simply upon metrics to manage a project.
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