Brief Summary
This video explains the crucial difference between a change in supply and a change in quantity supplied, a concept often confusing for economics students. A change in supply involves the entire supply curve shifting left or right, while a change in quantity supplied is simply a movement along the existing supply curve. Understanding this distinction is essential for success in economics.
- A shift of the entire supply curve signifies a change in supply.
- A movement along the same supply curve signifies a change in quantity supplied.
- Leftward movements indicate decreases, while rightward movements indicate increases in both cases.
Introduction
The video introduces the concepts of "change in supply" and "change in quantity supplied," acknowledging that these can be confusing for those new to economics. The video aims to clarify the difference between the two concepts using graphical examples.
Change in Supply vs. Change in Quantity Supplied
A change in supply is defined as a shift of the entire supply curve. A leftward shift indicates a decrease in supply, moving the curve from S1 to S2. Conversely, a rightward shift indicates an increase in supply, moving the curve from S1 to S3. In contrast, a change in quantity supplied is a movement along the existing supply curve. A leftward movement along the S1 curve, from point A to point B, represents a decrease in quantity supplied. The key is that there's no new supply curve; the movement occurs on the original S1 curve. Similarly, a rightward movement along the S1 curve, from point A to point C, represents an increase in quantity supplied, still on the same S1 curve.
Key Takeaway
The key difference to remember is that a shift in the entire supply curve (left or right) signifies a change in supply, while a movement from one point to another along the same supply curve signifies a change in quantity supplied. In both scenarios, a leftward movement indicates a decrease, and a rightward movement indicates an increase.
