[en] A measurement control program has been developed for the nondestructive assay (NDA) used in the Los Alamos Dynamic Material Control (DYMAC) system. The NDA instruments range in complexity from digital electronic balances to minicomputer based neutron and gamma-ray assay systems. The measurement control program serves two major functions. The first provides on-line checks of instrument accuracy and precision. The second function provides the data base necessary for defining and monitoring the systematic and random errors associated with individual instruments. The mathematical aspects of the measurement control program are presented and several specific examples of results discussed