In a standard supply-and-demand model, what does a rightward shift of the demand curve represent?

In a standard supply-and-demand model, a rightward shift of the demand curve represents an increase in demand.

An increase in demand means buyers want to purchase more at every relevant price, not merely more because the price has fallen. On a graph, the entire demand curve moves rightward. If supply remains unchanged, the new equilibrium generally has both a higher price and a higher quantity.

This differs from an increase in quantity demanded, which is a movement along the same demand curve caused by a lower price. Factors that can shift demand include income, tastes, the prices of related goods, population, expectations, and the number of buyers. The precise effect depends on which factor changes and whether the good is normal, inferior, a substitute, or a complement.

The model’s prediction is conditional. If supply also shifts, or if price controls, taxes, capacity limits, or external effects are present, the observed price and quantity changes may differ from the simple one-curve exercise.