Avoid "Design Specifications" |
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| Written by Graham Stoney | |
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Documents called “design specifications” have traditionally involved a combination of requirements and design decisions in the one document; which is something to avoid. The term “specification” is confusing because it implies “requirements” to some engineers and it implies “design” to others. I find it's symptomatic of a lack of distinction between the two, so I recommend avoiding the term “design specification” altogether. Either call the document a “requirements specification” or a “design description”, so it's clear whether it's a design input or a design output. Remember though that design decisions at one level in the system hierarchy impose requirements on the subcomponents at the next level down; so a design description will create outgoing requirements and it's appropriate for these to belong in the design description. For example, an electrical designer may decide that the best way to meet the accuracy requirements of his circuit is to use 0.1% tolerance resistors. This is a design decision which should be included in his design description. It imposes an outgoing requirement that must be met by all the resistor subcomponents. Social Bookmark this page:         
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