Shipping is a derived demand of the international trade, thus the type of commodities or the number of containers that a country imports and exports will vary from time to time. It is very difficult to predict either. Therefore it is essential to frequently update the forecast taking the trends of country’s external trade into consideration. The figure below illustrates that how different types of forecasts can be used in a sequential process. This helps to minimize potential risk of substantial gap between the original forecast and actual container stocks.