The Metric may be composed of one or more Measure dimensions or characteristics.
For example “Mean time between failure in operation” – has 3 defining Concepts – “time”, “failure” and “in operation”. This includes one “measure” (time).
A Complex Attribute specification, meaning one defined with a set of several Scales of Measure, is also a Metric expression. There is no implication that a Metric is “Elementary” (that it has only a single Scale).
Examples (Non-Metric Expressions):
“Easy to learn”.
“Very effective design”.
Each of these 3 expressions is based on a “non-metrics culture.” Nice words – no numbers expressed, defined or implied.
1. Metrics are used to express “Concepts of variability” clearly – in particular more clearly than mere words [GILB76].
2. The rationale for using metrics includes:
• to increase Clarity and unambiguousness of specifications
• to increase sensitivity to small changes in specifications and the System itself
• to enable Systems-Engineering logical thinking about relationships – for example the relation of designs to Requirements
• to provide a better Basis for legal contracting about Systems
• to enable Evolutionary tracking of progress towards Goals
• to enable a Process of learning within projects and Engineering and management domains
• to force engineers to think more clearly and communicate more clearly with others
-|-|-> “Scale with units” or ---> “Scalar Arrow, a simplified Keyed-Icon without explicit units”.
Several other defined Keyed-Icons can also be used to express a Metric (For example, Tolerable and Goal: O
This Concept entered by Adore Shuko.
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