Ideally a measurement device is both accurate and precise, with measurements all close to and tightly clustered around the true value. The accuracy and precision of a measurement process is usually established by repeatedly measuring some traceable reference standard. Such standards are defined in the International System of Units (abbreviated SI from French: Système international d'unités) and maintained by national standards organizations such as the National Institute of Standards and Technology in the United States.
ideally a measurement device is both accurate and precise with measurements all close to and tightly clustered around the true value the accuracy and precision of a measurement process is usually established by repeatedly measuring some traceable reference standard such standards are defined in the international system of units (abbreviated si from french système international d'unités) and maintained by national standards organizations such as the national institute of standards and technology in the united states