Positive economic profit is sometimes described as excess profit. 2. Predictability. The plan is made before the action, which aims to achieve the goals of the future, and to accomplish the next tasks and tasks. The independent of interest is of positive significance to show the active role of the fund users in the reproduction process. In the early 20th century, famous American economist elvin fisher developed the theory of economic gain. In its book "the nature of capital and yield", first, the concept of yield is analyzed in terms of the performance of earnings, and three different types of benefits are proposed: Canning's 1929 book, economics in accounting, cites the economist's view that asset values are determined by the present value of the future cash flows of assets.