Some psychological regularities of development and functioning of psychological standards under conditions of making estimations are considered. It has been shown that the n-dimensional structure of the psychological standards may not correspond to the n-dimensional structure of physical stimuli which generate them. In a number of cases multidimensional physical stimuli, for example, may generate both multi-dimensional and mono-dimensional psychological standards. Psychometric and psychophysical methods developed on the basis of the theory of standards are characterized by higher reliability and accuracy.