Therefore, macroplasticity theories based on amechanism involving long-range dislocation motion cannotserve to predict micro-yielding. In terms of measured stress–strain behavior, the two regimes are poorly distinguished,especially when they are characterized by positive strain-hard-ening, i.e., an increase in strength when the microstructure isstrained. To facilitate comparison of data, metallurgists havecome up with the rather arbitrary 0.2% definition of the mac-roscopic yield stress.