This publication provides guidelines for evaluating data from advanced mass calibrations and for establishing measurement assurance programs in precision mass calibration laboratories. The NIST Weights and Measures Division (WMD) will use these guidelines when evaluating advanced mass calibration data for State laboratories that request technical support, Recognition, and/or National Voluntary Laboratory Accreditation Program (NVLAP) accreditation.Advanced mass calibrations use weighing designs, such as those found in NBS Handbook 145 (SOP 4, 5), NISTIR 6969, Selected Publications, NBS Technical Note 952, and the NIST/SEMATECH e-Handbook of Statistical Methods that require the use of computer software (mass code) for the data reduction. These weighing designs are normally used when high precision (low uncertainty) mass measurement results are sought, although weighing designs can be used at any uncertainty level. The uncertainty reported using advanced weighing designs is based on the historically observed process of similar measurements and is very dependent upon correct procedures for defining these processes.