The vertical long-run aggregate supply curve captures the independent relation between the price level and aggregate real production. The price level does NOT affect long-run aggregate real production. A higher price level generates the same real production as a lower price level. However, from a graphical standpoint, it is possible to consider how changes in the price level can cause a movement along the long-run aggregate supply curve. To illustrate this, click the [Change Price Level] button.
In the analysis of the aggregate market, the price level generally changes in response to a disequilibrium in the economy. While the change in the price level leads to changes in aggregate expenditures on the demand side of the aggregate market and short-run aggregate real production, it does NOT cause changes in long-run aggregate real production. The price level change does cause a movement along the vertical long-run aggregate supply curve, but this is not associated with any quantity change.