In metrology and analytical chemistry, traceability refers to a property of measurement results. A traceable measured value is thus related to a recognized standard, such as an SI unit, by a continuous chain of comparison measurements with known measurement uncertainty. A calibration hierarchy or traceability hierarchy is taken into account in the comparison measurements. For perfect traceability, it must also be documented that each step has been carried out according to generally recognized methods and it must be ensured that the measurements are carried out by bodies that can confirm their competence for this by means of accreditation, if necessary. In addition, for optimum traceability, recalibrations must also be carried out at an appropriate frequency. Traceability with regard to measurement results represents a basis for almost all areas of measurement technology.