Which type of requirement concerns performance metrics?

• A. Functional
• B. Performance
• C. Prescriptive
• D. External

Answer: (B)

Performance metrics specify how well a system must perform by setting measurable targets and criteria that can be tested. This type of requirement describes outcomes in concrete numbers or thresholds, such as temperature stability within a certain range, energy use limits, or reliability over time. Because it focuses on quantifiable results and how success will be measured, it clearly targets performance rather than simply what the system should do (functional), how it should be built or what materials to use (prescriptive), or constraints coming from outside agencies (external).

Functional requirements describe the functions the system must perform without specifying exact metrics. Prescriptive requirements mandate specific products, systems, or methods. External requirements come from codes, standards, or other outside constraints. The emphasis on measurable outcomes is what makes performance the best fit for this question.