effective demand

In economics, effective demand (ED) in a market is the demand for a product or service which occurs when purchasers are constrained in a different market. It contrasts with national demand, which is the demand that occurs when purchasers are not constrained in any other market. In the aggregated market for goods in general, effective demand is the same thing as aggregate demand when the demand for goods is influenced by spillovers from quantity constraints from other markets. The concept of effective supply parallels the concept of effective demand. The concept of effective demand or supply becomes relevant when markets do not continuously maintain equilibrium prices.