This handbook was prepared with the objective of improving the understanding of the basis for the use of Standard Reference Materials (SRMs). While written from the viewpoint of a chemist, the basic concepts described are believed to be applicable to most areas of metrology. The handbook is arranged by section in a logical progression, starting with the basic concepts of precision & accuracy, followed by discussions of the calibration & quality assurance of the measurement process, the use of SRMs to evaluate various kinds of measurements, & the reporting of data with evaluated limits of uncertainty. Charts & tables.

Results of measurements and conclusions derived from them constitute much of the technical information produced by the National Institute of Standards and Technology (NIST). In July 1992 the Director of NIST appointed an Ad Hoc Committee on Uncertainty Statements and charged it with recommending a policy on this important topic. The Committee concluded that the CIPM approach could be used to provide quantitative expression of measurement that would satisfy NIST¿s customers¿ requirements. NIST initially published a Technical Note on this issue in Jan. 1993. This 1994 edition addresses the most important questions raised by recipients concerning some of the points it addressed and some it did not. Illustrations.