Aggregate supply refers to the total quantity of goods and services that firms in an economy plan to produce. It must be distinguished between the short run and long run. In the short run, aggregate supply is represented by the short run aggregate supply (SRAS) curve, which shows the relationship between output and the price level, assuming other factors are held constant. In the long run, aggregate supply is represented by a vertical line at full employment output. Factors that can cause the aggregate supply curve to shift include government supply-side policies, investment, changes in the labor market, and legislation.