Validating a requirement
Poor requirements lead to significant cost overruns as systems developed either do not meet the needs of the user or are not of usable quality.
Inadequately trained requirements engineers, stakeholders and requirement evaluators, inappropriate use of requirements analysis techniques, inconsistent processes & methods for engineering requirements, and inadequate usage and selection of requirements modelling and management tools, lead to poor requirements engineering.
Functional tests are essentially derived from requirements, and these requirements could be incomplete, incorrect, or over-specified.
The validation process involves reviewing a statistically valid sample of the assessments and making recommendations for future improvements to the assessment tool, process and/or outcomes if applicable.
The validation process also includes acting upon any recommendations for future improvement.
Generally, a use case in UML can be described as a sequence of system operations.
A system operation can be formally defined by a pair of preconditions and postconditions specified using OCL in the context of the conceptual class model.