This document discusses market measurement and forecasting. It explains that marketers measure and forecast the size, growth, and profit potential of market opportunities to identify opportunities and inform decision making. Several methods of measuring the total market, consumer demand, sales potential, and market share are described, including using total population, survey data, test markets, and historical sales analysis to estimate future demand. Levels of market measurement include consumer, product, geographic, and time. The purpose of demand forecasting is also outlined.