Existence of Quality and Testability of Quantity as Postulations in Educa- tional and Psychological Measurement System

Any measurement system must be in statistical control and the confirmation of measurability is the basic theoretical hypothesis in educational and psychological measurement. We analyze some assumptions in three measurement models in psychological and educational system through the history analysis and comparative study. Based on this, we propose three postulations in educational and psychological measurement: psychological and educational measurement object is an objective existence in “quality”; the "quantity" relative stability of the measuring object is unity of "quantity" relative invariance in individual objects and "quantity" difference in group objects; hypothesis of measurability of quantity: Psychological and educational measurement object can be measured in the "quantity". The study improves the theoretical postulations and provides a solid foundation for educational and psychological system measurement.