Shifting the Curve

Analogous to other determinants, aggregate demand determinants shift the aggregate demand curve. A change in any of the determinants can either increase or decrease the aggregate demand curve.

• An increase in aggregate demand is illustrated by a rightward shift in the aggregate demand curve. Click the [Increase in AD] button for a demonstration. What does it mean to have an increase in demand? It means that for every price level, the four sectors have an increase in aggregate expenditures on real production.


• A decrease in aggregate demand is illustrated by a leftward shift. Click the [Decrease in AD] button for a demonstration. What does it mean to have a decrease in demand? It means that for every price level, the four sectors have a decrease in aggregate expenditures on real production.

This suggests an important difference between two related changes--a change in aggregate demand and a change in aggregate expenditures.

• A change in aggregate demand is any shift of the aggregate demand curve. With this change, the entire curve shifts to a new location. A change in aggregate demand is caused by a change in the aggregate demand determinants. This is comparable to a change in demand in the analysis of the market.


• A change in aggregate expenditures is a movement along a given aggregate demand curve. This change involves the movement from one point on the existing curve to another point on the SAME curve. The curve does not move. A change in aggregate expenditures is caused by a change in the price level, and ONLY a change in the price level! This is comparable to a change in quantity demanded in the analysis of the market.