ISO/IEC 15415:2004(E) specifies two methodologies for the measurement of specific attributes of two-dimensional bar code symbols, one of these being applicable to multi-row bar code symbologies and the other to two-dimensional matrix symbologies; defines methods for evaluating and grading these measurements and deriving an overall assessment of symbol quality; and gives information on possible causes of deviation from optimum grades to assist users in taking appropriate corrective action. ISO/IEC 15415:2004(E) applies to those two-dimensional symbologies for which a reference decode algorithm has been defined, but its methodologies can be applied partially or wholly to other similar symbologies.