Function Allocation Systems Technique
FAST is an acronym for functional analysis system technique. FAST allows us to reduce ambiguity in the definition of a functional product or a functional process. Value of a product is interpreted differently by different customers. Characteristics that are common to value are high level performance, capability, emotional appeal, and style relative to its cost. Value is generally expressed in terms of maximizing the function.
Value = (Performance + Capability)/Cost
Value = Function/Cost