Needs? Statements of Need Are Always Inaccurate
I need a new car.
We need more water in So Cal.
Everyone needs medical care regardless of income
Anything worth doing is worth doing well.
These Statements Ignore Three Facts
Goods are not free. We must sacrifice something else we care about to get these goods.
There are substitutes for everything. (Everything?) Insulin? Self actualization?
Scarcity requires choices
Expected marginal costs and expected marginal benefits
The issue of scarce information
How Much of Something Someone "Needs"
Almost always related to the
sacrifice
required to obtain it.
The relationship is negative
Demand
A relationship between the amounts of
want fulfillment
and the
costs
of fulfilling those wants.
The Law of Demand - the relationship is
always negative
-
ceteris paribus
Exceptions?
Stocking up before some crisis - price up, quantity up
Prestige goods
Insulin to diabetics
What about relative prices and demand? Does inflation obviate the law of demand?
Individual demand
Market demand - the horizontal sum
l3d_is_h_sum
Values are subjective
People value things at the margin
"You like your Spanish class more than you like me." (Only at the margin.
The diamond - water paradox
How about a graph?
A change in demand
A change in quantity demanded
l3ch_in_d_qd
Time is an issue.
It takes time for consumers to find and for producers to provide substitutes.
In the textbooks, the changes are frictionless. In the real world?
Elasticity of Demand
A measure of
responsiveness
The amount by which...
The ratio
Percent change in...
If > 1, consumers are responsive
If < 1, consumers are unresponsive
If = 1, then ...
A calculation
Determinants of elasticity of demand
Time
Proportion of one's budget
The number of good, available substitutes
Luxury or not?
Elasticity and total revenue (P x Q)
If price increases and total revenues increase ...
If price increases and total revenues decrease ...
If price changes and total revenues don't change ...
l5d&tr
What about perfectly inelastic demand?
Elasticities L5
What about oil? Is there a difference between the long run and short run when it comes to people's responsiveness to a price change? (Time)
All Scarce Goods Must Be Rationed
Scarcity and rationing
Rationing methods
Fair?
Behavior and rationing
Rationing imposes costs - money and others
If money price is legally forced down then ...