Keynes shows that when the investment is more than saving, it leads to the inflationary situation in the economy. When saving becomes more than the investment, it leads to the recession. The idea of Keynes of the total expenditure of the government and its impact on the production and prices of goods also applies to investment. When the government spends more on growth then it leads to an increase in the private sector to invest more.

When a firm invests in physical assets and intangible assets, they take into account all the expected benefits of the investment.

Keynes's other ideas of investment also influence the unemployment level of an economy. It is because when investment in projects such as education and infrastructure is encouraged by the government, it affects the employment rate by providing opportunities to work.