Elasticity of Supply
Elasticity of Supply
Elasticity of Supply
Elasticity of Supply
The concept of elasticity of supply closely parallels that of elasticity of demand. Though
quantity supplied is influenced by a number of factors, we will focus on the commoditys
own price as a factor influencing supply. That is, we will be concerned with price
elasticity of supply.
Price elasticity of supply measures the responsiveness or sensitiveness of quantity
supplied of a commodity to a change in its price. It is given by the percentage change in
the quantity supplied of a commodity divided by the percentage change in price. Letting
(Greek letter epsilon) stand for the coefficient of price elasticity of supply, we have,
= percentage change in quantity demanded
percentage change in price
Being expressed in terms of relative or percentage changes, the price elasticity of
supply is a pure number. That is, it has no units attached to it. The value of price
elasticity of supply does not change when the units of measurement are changed. This
allows meaningful comparisons in the price elasticity of supply of different commodities.
Using the point elasticity formula
= Q/Q
P/P
That is,
= Q . P
P Q
Where Q represents change in the quantity supplied and P represents change in
price. Since quantity supplied and price move in the same direction, supply curves
normally have positive slope. Therefore, supply elasticity is normally positive. It will be
anything between zero and infinity (0< <).
Point elasticity of supply measures elasticity at a particular point on the supply curve.
More frequently, we measure elasticity of supply by using arc elasticity formula between
two points on the supply curve. Arc elasticity of supply measures the average of two
prices and the average of two quantities. Letting Pl refer to the lower of the two prices
and Ql being quantity and P2 to the higher of the two prices and Q2 the corresponding
quantity, we can measure arc elasticity of supply by
= Q . (Pl + P2)/ 2
P (Q1+Q2)/2
Or
= Q . (Pl + P2)
P (Q1+Q2)
Degrees of Supply Elasticity
When the supply curve is upward sloping, the elasticity of supply will be anything
between zero and infinity. On the basis of the value of the coefficient of elasticity of
supply we can classify it into the following five categories: (i) Perfectly inelastic supply,
(ii) Inelastic supply, (iii) Unitary elastic supply , (iv) Elastic supply, (v) Perfectly elastic
supply. Let us each one of them in detail.
When the quantity supplied of a commodity does not change at all in response to the
change in price, elasticity of supply is said to be perfectly inelastic. This is the case of
zero elasticity ( = o) and the supply curve will be vertical straight line, as shown below.
The supply curve has zero elasticity since the same quantity Q is supplied whatever the
price.
If the percentage change in quantity supplied is smaller than the percentage change in
price, supply is said to be inelastic. The value of the coefficient of supply will be greater
than zero but less than unity (0<<1). If a linear supply curve crosses or cuts the
horizontal (quantity) axis, supply is inelastic, as shown below.
The time period under consideration has a significant effect on the price elasticity of
supply. If the time period is very short, an increase in price does not significantly affect
the quantity offered for sale. If a certain quantity of a commodity has already been
produced and brought to the market, an increase in price does not cause a large
quantity to be offered for sale, because the quantity is fixed. As the time period under
consideration becomes longer, supply tends to become more elastic. Sellers will be able
to respond more easily to changes in the prices of their products.
(2) Change in cost of Production
Elasticity of supply of a commodity depends upon the ease with which increases in
output can be obtained without bringing about a rise in cost of production. It also
depends on how easily producers can shift from the production of other products to the
one whose price has risen. For example, if agricultural land and labor can be readily
shifted from one crop to another, the supply of any one crop will be more elastic than if
labor cannot be shifted.
The business firms must take into account the elasticity of demand when they take
decisions regarding pricing of products. This is because change in price of a product will
bring about change in quantity demanded depends upon the coefficient of elasticity. If
the demand for the product of the firm happens to be elastic, then any attempt on the
part of the firm to raise the price will bring about a fall in total revenue. Thus instead of
gaining from the increase in price, it will lose substantial part of its revenue. On the
other hand, if the demand for the product happens to be inelastic, then increases in
price will lead to increase in total revenue. Thus, for fixing an optimum or profit
maximizing price, the firm cannot ignore the elasticity of demand for the product.
(2) Government Tax Policy
The elasticity of demand is also significant in the field of tax policy by the government.
Government must take into account the elasticity of demand for the product before
imposing and/or tax on it. This is because it is only when tax is imposed on the
commodity with price inelastic demand, which will raise a great deal of revenue of the
government. At the same time, if the demand for the commodity is price elastic, a rise
in price caused by tax will bring about large decline in quantity demanded and as a
result government revenue will also decline