Shift in Demand: D to D′

This diagram shows a rightward shift in demand from D to D′. At the same price \(P_0\), the quantity demanded increases from \(Q_0\) (on the original curve D) to \(Q_1\) (on the new curve D′). The arrows between the curves show the direction of the shift.

A demand shift occurs when a non-price determinant of demand changes, such as consumer income, tastes, expectations, population, or the price of related goods. The entire curve moves, meaning that at every price level consumers now want to buy more (rightward shift) or less (leftward shift). This is fundamentally different from movement along a single curve, which is caused by a change in the price of the good itself.