Combine intel on past demand for products and services with market conditions to forecast future demand. Use this as an input for production planning, capacity planning, facility layout planning, marketing activities and inventory management.
The simplest method to forecast demand, known as the Trend Method is to assume that ceteris paribus, the demand pattern over the past few time periods, will be the pattern of growth in the future. A more comprehensive approach is to define a relationship between various factors affecting the demand such market conditions, income and demographic conditions from the target segment and seasonal trends to forecast the demand.
More approapritely used when the offering is new to the market and previous data is not available, customer surveys on what they intend to buy and how much they are willing to spend on it, from sales persons on the expected sales in their area and corresponding cumulation or market and expert surveys can be ways to predict demand