This document discusses demand forecasting techniques used to predict future demand for products and services. It covers qualitative methods like executive opinion and surveys, as well as quantitative time series and causal models. Time series methods explained include moving averages, trend projection using least squares, and exponential smoothing. Causal models relate demand to factors like income, price, and leading economic indicators. The document notes uncertainties in demand forecasting arise from limitations of past data, unrealistic assumptions in models, and changes that are difficult to predict.