What is the difference between performance-based and prescriptive specifications?

What is the difference between performance-based and prescriptive specifications?

• A. Performance specs define outcomes; prescriptive specs specify exact materials and methods to achieve those outcomes
• B. They are never used together
• C. They are identical in purpose
• D. Performance specs specify exact materials; prescriptive specs define outcomes

Answer: (C)

In construction specifications, the focus can be on the result or on the means to achieve it. Performance-based specifications state the required outcome or performance criteria and allow the contractor to choose the materials and installation methods that meet that goal, as long as the performance is verified by tests or calculations. Prescriptive specifications demand specific products, materials, and construction methods to be used, leaving little room for substituting alternatives. They are not the same because one centers on what the finished work must do, while the other centers on exactly how it must be built. They can be used together, for example by tying a performance criterion to a list of approved materials or installation practices.

In construction specifications, the focus can be on the result or on the means to achieve it. Performance-based specifications state the required outcome or performance criteria and allow the contractor to choose the materials and installation methods that meet that goal, as long as the performance is verified by tests or calculations. Prescriptive specifications demand specific products, materials, and construction methods to be used, leaving little room for substituting alternatives. They are not the same because one centers on what the finished work must do, while the other centers on exactly how it must be built. They can be used together, for example by tying a performance criterion to a list of approved materials or installation practices.