Price Theory

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Do markets tell us the value of things?
 What is value?
 Why are diamonds worth more than water?
 Use value
 Exchange value
 Do markets tell us how scarce things are?
 Why did oil prices remain flat for 100 years?
 Why did we harvest North Atlantic Cod almost to extinction with only small price increases?

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Markets equilibrate supply and demand
 Does this mean everyone can satisfy their demand for anything?
Rationing function of price
Allocative function of price

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Marginal utility MU xn,
MU yn,
MU xm,
MU ym
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What’s the marginal utility of a cure for African sleeping sickness to someone dying of African sleeping sickness?
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What’s the marginal utility of Vaniqa to someone with excessive facial hair?
Commodities are the outputs of production. Commodity prices
(P x
=cost of life saving medicines
,
P y
= cost of cosmetics)
Factors are the inputs to production. Factor prices = P a ,
P b,
P c

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P a the wage of a scientist needed to develop the commodity
P b the cost of laboratory equipment to produce the commodity
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P c the cost of raw materials (e.g. eflornithine)
Marginal Physical Product (MPP ax,
MPP ay,
MPP bx,
MPP by,
)
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Assumes other factors are held constant
The laws of physics: can you produce more pizza just by hiring more cooks?

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All firms and consumers are price takers
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How do prices change?
Plans are adjusted to prices

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Law of diminishing marginal utility
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Assume the opposite, increasing marginal utility
Law of diminishing marginal physical product
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Assume the opposite, increasing marginal physical product.
What about economies of scale?

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Equimarginal principle of maximization
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Consumer's equimarginal principle of utility maximization
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MU xn
/P x
= MU yn
/P y
Rearrange to get MU xn
/MU yn
= P x
/P y

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Equimarginal principle of maximization
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Producer's equimarginal principle of profit maximization

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MPP ax
/P a
=MPP bx
/P b
How does this relate to the price of X and Y?
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P a
=P x
(MPP ax
) = P y
(MPP ay
) or P x
=P a
/MPP ax
= P y
=P a
/MPP ay

Rearrange to get MPP ay
/MPP ax
=P x
/P y
Which industries get the resources?
Which industry can afford to pay the most for scientists, laboratories and raw materials, life saving medicines for the poor or cosmetics for the rich?
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Allocative function of price

MUxn / MUyn = Px / Py = MPPay / MPPax

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MUxn/MUyn = rate at which consumers are willing to substitute X for Y (psychological rate of substitution)
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Px/PY = rate at which consumers are able to substitute X for Y (Market rate of substitution)
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MPPay/MPPax = rate at which producers are able to produce ‘transform’ one good into another (technical rate of transformation) by reallocating factors of production

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Equation holds for all consumers m, n, o
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All products x, y, z
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All factors of production a, b, c
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Decentralized information

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Markets balance what is possible with what is desirable
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Resources flow to those who value them most
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Leads to ‘optimal’ allocation of resources
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Consumers maximize utility
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Producers maximize profits

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So does society produce the right balance of life saving diseases and cosmetics?
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Who values eflornithine most, dying Africans or hairy women?
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Rationing function of price
Pareto optimality: Everyone is as well off as can be without making someone else worse off.
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How do we choose between Pareto Optimal outcomes?
Many other reality checks to come!

Other assumptions not mentioned?
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Do things that are not bought and sold compete for resources with things that are?
Can everyone participate in the market?

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Monopolists are price makers
Marginal revenue for monopolist is less than price
Monopolists maximize profits by producing less than is socially ‘optimal’.
Are monopolies relevant to the eflornithine example?

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How can we alter the desirability conditions (MU ratios?)
How can we alter the possibility conditions
(MPP ratios)
What would happen if we redistributed wealth?

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MUxn/Px=MUyn/Py
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Let y = money, and let Py = 1.
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Then MUxn/Px=MUmn, and
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Px = MUxn/MUmn.
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We keep trading money for good X until we maximize utility.

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Px = MUxn/MUmn
How do we adjust if Px drops?
What part of this demand curve corresponds to
Africans’ demand for eflornithine?

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Px=MCx
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This is the condition for being on the supply curve
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Remember that we are assuming increasing marginal costs.
Px=MCx=Pa/MPPax=Pb/MPPbx=...
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Remember units. Px=$/X, Pa/MPPax=$/X
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Look at Px=Pa/MPPax. Say Px increases. Pa stays the same, so MPPax must decrease. More a must be used, so Q increases.

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Supply curve

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Supply and demand together
MUxn/MUmn=Px=Pa/MPPax
MUyn/MUmn=Py=Pa/MPPyx

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Can we make more pizza by simply using more ovens or more cooks?
Markets make decisions based on the principle of one dollar, one vote. Is this appropriate for all resources?
Do you think markets allocate scientists towards their best possible use?
What about information?
Many ecological economists are trying to price non-market goods and services (e.g. ecosystem services). If we could do this, would it lead to their optimal allocation?