1. Market Prices with Shifts: EQUILIBRIUM, part II Ch. 6, Sect. 4-5
What do economists ask when an event causes a curve to shift, changing equilibrium?
How do you graph those changes?
What do prices do in a mixed economy?

2. Review
In our hypothetical market, we met equilibrium by changing prices, so Qd=Qs.
We know that a change in Qd or Qs (due to price) means we move along the curve.
When the Qd and Qs lines intersect, you have an equilibrium point

3. What happens when there is an overall change in demand or supply?
However, if overall D or S changes due to anything other than price (shifters), then the entire curve will shift left or right.
This shift, in turn, would have an effect on market equilibrium and the equilibrium point
To analyze this effect, economists ask three questions:
Does the event affect demand, supply, or both?
Does the event shift the demand or supply curve to the right or to the left?
What are the new equilibrium price and quantity, and how have they changed as a result of the event?

4. Let’s see what would happen…
What might happen if new medical research were to identify blueberries as a powerful “brain food.” How would this event affect the blueberry smoothie market?
Think back to the three questions:
Does the event affect demand, supply, or both?
affects the demand for blueberry smoothies
consumers buy more foods made with blueberries because they think eating blueberries will make them smarter
little or no immediate impact on the supply of blueberries

5. The event shifts the demand curve to the right
Does the event shift the demand or supply curve to the right or to the left?
The event shifts the demand curve to the right
demand for blueberry smoothies before the research D1
demand after the report’s release is shown by the new curve, D2
D2 curve is right
of D1 curve
This shift shows
us an increase in
demand

6. Due to increased demand, new equilibrium price: $3.00.
What are the new equilibrium price and quantity, and how have they changed as a result of the event?
Due to increased demand, new equilibrium price: $3.00.
New equilibrium quantity is 4,000 smoothies
If the juice bar owners had kept price of smoothies at $2.50 after new demand= shortage
At $2.50, consumers would have demanded 5,000 smoothies, but the producers would have been willing and able to supply only 3,000.
By raising the price to $3.00, the producers found the “right” price—the equilibrium price, at which the quantity demanded equals the quantity supplied.

7. Let’s see what would happen…
How might a long summer drought in major blueberry-producing states like Maine affect the market for blueberry smoothies? Suppose the blueberry harvest is half of the average amount. What impact would this have on the market?
Does the event affect demand, supply, or both?
The drought (and later bad harvest) affect supply by driving up the cost of blueberries, one of the raw materials used in the production of blueberry smoothies.
higher input costs cause producers to supply fewer smoothies at every price
no impact on demand; higher cost of blueberries doesn’t change number of smoothies people want to buy

8. Does the event shift the demand or supply curve to the right or to the left?
production of smoothies has decreased at every price, so supply curve moves to the left
new supply curve, labeled S2, is to the left of S1

9. What are the new equilibrium price and quantity, and how have they changed as a result of the event?
new equilibrium price is $3.00
new equilibrium quantity is 2,000 smoothies
drought has caused the equilibrium price to increase and the equilibrium quantity to decrease.
If producers had not raised the price of smoothies, a shortage would have occurred.

10. Let’s see what would happen…
A bestselling book calls the blueberry “a miracle fruit” that promotes good health. At the same time, a supermarket chain says it’s opening juice bars in most of its local stores.
Do the events affect demand, supply,
or both?
The events are likely to affect both demand and supply.
book motivates consumers to buy more blueberry smoothies, so Qd increases at all prices
juice bars cause an increase in the number of producers, so Qs increases at all prices

11. Do the events shift the demand or supply curve to the right or to the left?
Qd and Qs increase at all prices --both curves shift to the right
new curves, D2 and S2, are to the right of first curves, D1 and S1.
Shows increase in both demand and supply

12. What are the new equilibrium price and quantity, and how have they changed as a result of the event?
While both D and S increased, demand for smoothies increased even more than supply has.
equilibrium price from $2.50 to $3.00, equilibrium quantity from 3,000 to 6,000 smoothies
if the juice bar owners had not raised the price by 50¢, a shortage of 2,000 smoothies would have occurred
In the real world, demand and supply are continually shifting in response to events. The impact of such shifts is not always immediately clear.
usually takes time for economists to understand effects of demand and supply shifters on markets.
when a product’s demand and supply both increase, economists are safe in predicting that the equilibrium quantity of that product will increase.
can’t tell with any certainty how the equilibrium price will change.
In our simplified model of a market, the equilibrium price increased. In a real market, the equilibrium price could increase, decrease, or stay the same.

13. Check yourself…
What happens to the graph if there is only a change in price?
What happens to the graph due to a D/S shifter?
What happens to the graph when both supply and demand increase?
THINK: What happens to the graph when demand increases but supply decreases?