Aggregate Supply in the Short Run
Production takes place in business sector on the basis of an expected price for its output. However, costs are incurred in anticipation of sales. This is the risk of production since firms cannot know in advance how much this output will sell for. If the actual price achieved exceeds the expected price, firms will experience a higher than anticipated level of profits and this will encourage an increase in production. This implies that the short run AS curve slopes upward from left to right for part of its range because at any point in time there is a limit on the output of goods and services. This limit increases as with increased production, the availability of idle resources decreases and this 'limit' is reached when the production reaches full employment level of output. When the resources available are fully employed the short run aggregate curve will become vertical. At this point, further increases in price level will have no effect on output.