- [Instructor] We've done many videos
on the price elasticity of demand,
now we're going to focus on
the price elasticity of supply.
And it's a very similar
idea, it's just being applied
to supply now, it's a
measure of how sensitive
our quantity supplied is to
percent changes in price.
And we will calculate
it as our percent change
in quantity supplied for a given,
for a given percent change in price,
percent change in price.
Now, to make this a
little bit more tangible,
let's look at a simple market,
let's say this is the market
for apples, right over here,
where our vertical axis is price,
and this could be thousands
of dollars per ton,
and then our horizontal
axis is quantities,
and maybe this is in tons per day.
And this supply schedule
and this supply curve
are essentially describing the same data.
So, let's think about our
price elasticity of supply
as we go from point A,
point A, to point B.
Well, on the supply schedule,
point A is this point
right over here, our price
is four, our quantity is one.
And point B is right over here.
So let us calculate
from point A to point B
our price elasticity of supply.
So, first of all, what is going to be
our percent change in price?
Well, we're going from four to six,
so it's an increase of two,
so our percent change in price
is going to be equal to two,
is how much we increased
from a base of four,
times 100% and that of course
is going to be equal to
a 50% increase in price.
And then what is going to be
our percent change in quantity?
Well, we're going from one to two,
so we're starting at a base of one.
We are increasing by one,
and then multiply that
times 100%, that gives us 100%.
So, when we have a 50% increase in price,
that resulted going
from point A to point B,
in a 100% increase in quantity supplied.
So, 100% divided by 50%,
that is going to give us,
this is going to be equal to two.
Now, what if we go from
point B to point C?
So, this is point C right over here.
I encourage you, pause this video
and see if you can calculate
the price elasticity of supply
when going from point B to point C.
Well, we're going to do
a similar calculation.
Our percent change in price.
We start at a base of six
and we are increasing by two.
So we're gonna multiply that times 100%.
So that is approximately,
this is 1/3 times 100%,
so approximately 33.3%.
And then what is our percent
change in quantity supplied?
Well, we are going to
go from two to three.
So we start at a base of
two, we increase by one.
So plus one, and multiply times 100%.
And so that's going to be given,
it's going to be equal to 50%.
And so when we have a 1/3 increase,
or 33.3% increase in our price,
we have a 50% increase
of our quantity supplied,
when we go from point B to
point C right over here,
and then one way to think about it is
50% divided by 1/3 is the
same thing as 50% times three,
and so this is going to be equal to,
this is going to be equal to 1.5.
So, just as we saw when we calculated
price elasticity of demand,
either when you have a linear curve here,
your price elasticity
of supply can change.
It is not the same thing as slope.
Now another thing to
keep in mind is the way
that I calculated price elasticity
of supply in this video,
which is arguably the simplest way,
you would not get the same value
when you're calculating the
magnitude going from A to B
than if you went from B to A.
There are slightly more
advanced techniques,
the mid-point technique, for example,
that will give you the same answer
regardless of which direction you go in,
but that's beyond the
scope of this first video.
Now, just as we discussed
in the demand case,
there are cases that you would consider
to be more inelastic supply and cases
where you would consider
to be more elastic supply.
So, one way to think about it is,
if the magnitude of your
price elasticity of supply
is less than one, and of
course this is magnitude
so it's going to be greater
than or equal to zero,
well, then you're talking
about inelastic price
elasticity of supply, inelastic.
That's a situation in
which our quantity supplied
is not going to change
so much depending on,
is not going to be so sensitive
to our change in price.
Now, if our price elasticity of supply
is greater than one,
that's generally considered
to be elastic, for a given
percent change in price,
you're getting a larger than that percent
change in quantity supplied.
