Supply
- Supply is the amount of a good/service that a producer is willing and able to supply at a given price in a given time period
- A supply curve is a graphical representation of the price and quantity supplied by producers
- If data were plotted, it would be an actual curve, however economists simplify curves in their sketches into straight lines so as to make analysis easier
- The supply curve is sloping upward as there is a positive relationship between price and quantity supplied
- Rational profit maximising producers would want to supply more as prices increase in order to maximise their profits
A supply curve showing an extension in quantity supplied (QS) as prices increase and a contraction in quantity supplied (QS) as prices decrease
Diagram Analysis
- If price is the only factor that changes (ceteris paribus), there will be a change in the quantity supplied (QS)
- This change is shown by a movement along the supply curve
- An increase in price from £7 to £9 leads to a movement up the supply curve from point A to B
- Due to the increase in price, the quantity supplied has increased from 10 to 14 units
- This movement is called an extension in QS
- A decrease in price from £7 to £4 leads to a movement down the supply curve from point A to C
- Due to the decrease in price, the quantity supplied has decreased from 10 to 7 units
- This movement is called a contraction in QS