User requirement specification (URS)

The document in which the user defines what equipment, a utility or a computerized system must do: capacity, performance, materials, GMP and data integrity requirements, and constraints. It is the starting point of the V-model; design qualification checks the design against it, and performance qualification checks the result against it. Japanese documents use the Japanese name and URS interchangeably. Requirements missing from the URS are hard to verify later, because every qualification test should trace back to a requirement.