Teacher's estimation behavior is both an important and delicate means of conveying positive social experience to the schoolchildren and a significant regulator of development in them of adequate self-appraisal. An experimental study has been performed which helps to establish proper relations between the above processes and to reveal corresponding mechanisms and factors. Formulas for measuring discrepancy between child's real and assumed personality characteristics, for general group estimation of a personality, and for integral self-estimation by the adolescent are suggested.