The definition of instrument performance for contract and metrological purposes

An instrument specification is intended to define its performance for any purpose where this is important. When an instrument is being chosen and purchased, the specification is one of the most significant features which decides to which company the contract will be awarded. When the instrument is put into service, the user will depend on the specification to satisfy himself that his measurements are of the required parameter and quality. The user may also have to convince an independent assessor of these. The author discusses the origin and purpose of specifications and discusses problems due to the ambiguity and lack of uniformly interpretable data