how do you calculate economic profit Interest rate, in the form of expression, refers to the ratio of the amount of interest to the total amount of borrowed capital in a certain period of time.  the interest rate is the interest level per unit time of the unit currency, indicating the interest rate. Economists have been looking for a theory that can fully explain the structure and change of interest rates. Interest rates are usually controlled by the central bank of the country and administered by the federal reserve board in the United States. Today, interest rates are one of the important tools for macroeconomic regulation. Diversification of securities, the establishment of a scientific and effective portfolio of securities; But even so, the average gain was 0.14 percentage points, to 4.74 percentage points, Moneyfacts said. In just three days, the 30-year bond jumped 16 basis points, the biggest gain since December 2008. 6. Clarity. Plan should be clearly expresses the organization's goals and tasks, clearly expresses the resources necessary to achieve goals and taken by the procedures, methods and means, explicitly expresses the managers at all levels in the rights and duties in the process of execution plan.