The law of the cost of personal education investment (that is, the money spent on training a talent) and the value that this person can penetrate after training. According to the different education levels of the whole group (such as China people), divide the overall average water consumption of this group when they are educated, compare the returns generated by this group in their later years, and then draw a rule according to this data.

Internal interests

The direct consumption utility of education is the growth of the educated's knowledge and ability and the cultivation of their conduct and values, which belongs to the internal output or internal benefit of education.

External benefit

The indirect consumption utility of education refers to the increase of knowledge and ability and the internal output of good conduct and values, which improves the productive capacity, creative ability and civilization of the educated, enables the educated to obtain higher income and status in the labor market and social activities, and promotes social economic growth and social development harmony. This effect belongs to the external output or external benefit of education.

Direct consumption of education

From the perspective of direct consumption, education is competitive and exclusive. The marginal cost of adding a student is not zero, which will reduce the level of educational services received by the original students. For example, the average attention of teachers will be reduced, and the average school area, books, instruments and other educational resources will be reduced. Technically speaking, schools are fully capable of excluding consumers of education (such as non-payers) from schools or classrooms. Therefore, the direct consumption of education has the nature of private products.