The technology of bar coding is based on the recognition of patterns encoded in dark and light elements of defined dimensions according to rules defining the translation of characters into such patterns, known as the symbology specification.

The bar code symbol, as a machine-readable data carrier, must be produced in such a way as to be reliably decoded at the point of use, if it is to fulfil its basic objective. Standard methodologies have been developed for measuring and assessing the quality of symbols for process control and quality assurance purposes during symbol production as well as afterwards.

Manufacturers of bar code equipment, the producers of bar code symbols and the users of bar code technology require publicly available standard conformance specifications for measuring equipment applying this methodology, to ensure the accuracy and consistency of performance of this equipment.

ISO/IEC 15426-1:2006 defines test methods and minimum accuracy criteria for verifiers using the methodology of ISO/IEC 15416 for linear bar code symbols, and specifies reference calibration standards against which these should be tested. ISO/IEC 15426-1:2006 provides for testing of representative samples of the equipment.