How do short-run and long-run aggregate supply differ?

• A. Short-run is constant; long-run is variable
• B. Short-run is influenced by temporary factors; long-run reflects full capacity
• C. Both are unaffected by external economic factors
• D. Short-run is determined by market equilibrium; long-run is determined by fiscal policy

Answer: (B)

The distinction between short-run and long-run aggregate supply is fundamentally tied to the timeframes in which prices and production levels can adjust to changes in economic conditions. In the short-run, aggregate supply can be influenced by temporary factors such as supply shocks, wage adjustments, and fluctuating resource prices, which can lead to changes in output and pricing without a full adjustment in all input costs. This means that firms may react to increased demand by increasing production, but not all factors of production can be adjusted immediately.

Conversely, the long-run aggregate supply reflects the economy's full capacity to produce goods and services when all prices, including wages, have adjusted fully. In this context, the long-run aggregate supply is often conceptualized as being vertical, indicating that it is not influenced by the price level but rather by technology, resources, and productivity at full employment. Thus, it represents a state of equilibrium where the economy is producing at its potential output.

This understanding illuminates why option B effectively captures the essence of the difference between short-run and long-run aggregate supply, highlighting the temporary influences in the short run versus the structural, capacity-driven nature of long-run aggregate supply. The other options do not accurately encapsulate these fundamental concepts.