Soft goal
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The term soft goal is used in connection with modeling languages and specially with goal-oriented modeling. Soft goals can represent:
- Non-functional requirements
- Relations between non-functional requirements
Non-functional requirements (or quality attributes, qualities, or more colloquially "-ilities") are global qualities of a software system, such as flexibility, maintainability, usability, and so forth. Such requirements are usually stated only informally; and they are often controversial (i.e. management wants a secure system but staff desires user-friendliness). They are also often difficult to validate.
[edit] Why soft?
Normally a goal is a very strict and clear logical criterion. It is satisfied when all sub-goals are satisfied. But in the non-functional requirements you often need more loosely defined criteria, like satisfied or unsatisficeable. Soft goals are goals that do not have a clear-cut criterion for their satisfaction: they are satisfied when there is a sufficient positive and little negative evidence for this claim, while they are unsatisficeable in the opposite case.
[edit] Relations between soft goals
- AND
- OR
- +
- -
