Generally , forecasting , is the prediction of outcomes , trends , or expected future behavior of a business , industry sector or even the economy.
Put in another way , it is a projection of economic activities over a particular time period.
Sales forecasting , therefore , is the process of estimating future sales. Accurate sales forecast enable companies to make informed decisions about the level of production , manpower needs , imputs and other short and long term requirements.
Companies can base their forecast on both endogenous and exogenous factors .e.g. government policies , past sales performance , activities of their competitors and the general economic trend.