Source: https://www.lexology.com/
William J. Tinsley, Jr., Phelps Dunbar LLP

An owner’s traditional design (or prescriptive) specifications give the contractor specific, step-by-step details for construction. If the contractor builds a project according to design specifications, it has no liability for the design.

In contrast, true performance specifications focus upon the owner’s requirements for the finished project. Performance specifications afford significant discretion to the design builder for the design as long as the finished project meets the owner’s requirements. It is this discretion that shifts the responsibility for design to the builder, who by operation becomes a design builder. Read more.