Page 427 15.1. What is the aggregate demand-aggregate supply model? How do aggregate demand and aggregate supply differ from product-specific demand and supply? Product-specific demand and supply describe a market for a given good from the point of view of a single firm, whereas aggregate demand and aggregate supply describe the market from the point of view of all firms in the market. Product-specific demand and supply describe a market at a moment in time, whereas aggregate demand and aggregate supply describe the same market over an entire economic cycle. Product-specific demand and supply describe the market for a single good, whereas aggregate demand and aggregate supply describe the combined market for all final goods and services