Another classification of investment, private investment and public investment will be used. Private investment is the private account, ie private and public investment by the government. Private investment is the marginal efficiency of capital, ie affected the expectations of profits and interest. And good-elastic. Public investment in the state and local authorities, such as construction of roads, public parks, etc. made in public investment, no gain has not come into consideration. For social good and not for private purposes.

The investment is independent of income level, is autonomous investment. Such an investment does not vary with income level. In other words, the income is inelastic. Autonomous investment depends more on population growth and technological progress than anything else. The impact of changes in income can not be excluded completely, because higher income would probably lead to more investment. But the impact of income is negligible compared to the influence of population growth and the progress of technical knowledge.

Examples of individual investments are investments in long-term housing, roads, public buildings and other forms of public investment. The bulk of investment is intended to promote economic development planned. It also contains long-term investments to achieve technical progress or innovation to produce. Public investment, an investment that occurs as a direct response to the invention, and the most long-term investment that will for themselves over a long period can be considered as pay for the individual investments.