Describes a "reference" method for the determination of the residual resistance ratio (RRR) of a composite superconductor comprised of Nb-Ti filaments and Cu, Cu-Ni or Cu/Cu-Ni matrix. This method is intended for use with superconductors that have a rectangular or round cross-section, RRR less than 350, and cross-sectional area less than 3 mm2. All measurements shall be done without an applied magnetic field.Optional acquisition methods are outlined in annex A.