To verify whether the deformation of the bulk test specimens represents that of small solder joints, we have used the concept of "representative volume." The representative volume is defined as the smallest volume which represents the average inelastic and inhomogeneous deformation of the entire body. We have performed the first set of experiments to determine this representative volume by measuring the microscopic deformations of a large Pb/Sn eutectic alloy specimen as a function of applied strain. The results show that the representative volume of the specimen is very large compared to the size of the solder joints. © 1992 The Minerals, Metals and Materials Society, and ASM International.