Changes in Demand Versus Changes in Quantity Demanded

The foregoing discussion showed that sometimes there are movements along an existing demand curve and sometimes the demand curve actually shifts to the left or to the right. Distinguishing one from the other is very simple. A change in demand is not the same as a change in the quantity demanded. A change in the price of a good causes a change in the quantity demanded. For example, a higher price causes a lower quantity demanded for the good considered. On the other hand, change in demand or a shift of demand occurs when there is a change in the determinants of demand, other than the price. Changes in the determinants of demand, other than price cause a change in demand, or a shift of the entire demand curve from, say, D₀ to D₁.