Socialist society interested in the maximum saving of social labor in order to satisfy most fully the needs of all of its members. The saving of labor requires the appropriate reckoning and estimation of the social labor input required for the production of various goods. The magnitude of the input of social labor-time in the production of a given article not constant but changes with every variation in the productive power of labor. The latter is determined by various circumstances, among others by the average degree of skill of the workmen, the state of science and the degree of its practical application, the social organization of production, the scale and effectiveness of the means of production, and by natural conditions.