- [Instructor] What we see here
is an economy with an output gap.
As you can see, the short run equilibrium output
is below our full employment output.
This is sometimes referred to as a recessionary output gap.
And in other videos, we talk about how there could be
a self-adjustment mechanism in the long run,
that because we are below full employment,
folks who maybe, especially folks who wanna get a job,
might say, "Hey, I'm willing to work for less and less."
And maybe our short run aggregate supply curve
shifts down over time
and we get to a state, something like this,
and in that case, so this would be
our short run aggregate supply curve two,
and in that case, all of a sudden,
we would be in a long run equilibrium
where our equilibrium output
is equal to our full employment output.
But let's say that does not happen.
Let's say we are in a world where, for some reason,
we stay sticky with this negative output gap
and you are the government
and you wanna do something about it.
You wanna get back to full employment output.
Well, there's a couple of levers.
You have fiscal policy,
fiscal policy, which is all about changing
how much you spend, so this would be government spending.
Let me make it clear.
This is government spending.
Or changing the amount of taxation.
So, the theory is if the government spends more,
that would increase total output
and then the other theory is if the government taxes less,
there's more money out in the economy
and that could also increase total output.
And there's also monetary policy,
which we're not gonna go into detail in this video,
but monetary policy is messing with the money supply.
If maybe there's more money out there,
lower interest rates, it might increase output,
and then the opposite could be true the other way.
But we are going to, so let me just write this.
This is the money supply.
Money supply/interest rates.
Interest rates.
And this would be the business of a central bank.
But we are going to focus on fiscal policy.
So as a government, what we want to see happen
is this aggregate demand curve shift to the right,
so we want it to get to a place like this.
We want our aggregate demand curve
to shift to the right just like this,
so this would be aggregate demand two.
And how do we do that?
How do we get this shift right over here
so that we get to our full employment output?
Well, there's two levers that we can think about.
As we just said, government spending and taxation.
Now, a big misconception is a lot of folks say,
"Well, if I increase spending by a hundred billion dollars,
"that's equivalent of reducing taxes
"by a hundred billion dollars
"because there would be a hundred billion more dollars
"out there in the economy to increase output."
But you have to be very careful.
Remember what we learned about multipliers,
and remember, these are all very simple models,
but a regular multiplier, let me write it over here,
a regular multiplier,
a regular multiplier is one
over one minus the marginal propensity to consume,
while our tax multiplier,
tax multiplier
is equal to, so if you have an increase in taxes,
that would be the negative
of the marginal propensity to consume
over one minus the marginal propensity to consume.
The negative would be if you increase taxes
that is going to have a negative total effect on spending.
And the reason why you have
this marginal propensity to consume in the numerator
is if I were to have my taxes reduced
by, say, a hundred dollars,
depending on my marginal propensity to consume,
if my marginal propensity to consume
is less than one, which it typically is,
I'm not gonna spend all that hundred dollars.
I am going to spend some fraction of it,
really the marginal propensity to consume
times a hundred dollars.
While if the government just goes out there
and spends a hundred dollars,
well, that hundred dollars got spent.
And to see the impact, the difference in impact,
let's go through it a little bit, let's do an example.
Let's say a situation where the government,
the government just spends $100 billion.
So, the government wants to spend $100 billion.
What is going to be the impact?
And let's say we're in a world
where our marginal propensity to consume is equal to 0.8.
What is going to be the effect
on the economy in this situation right over here?
Well, in this situation, you're going to have
a hundred billion dollars of spending
times, you're gonna multiply it times the multiplier,
one over one minus our marginal propensity to consume, 0.8,
and so this is going to be equal to $100 billion,
$100 billion
divided by 0.2.
Well, 0.2 is 1/5, so this is going to be the same thing
as dividing by 1/5 or multiplying by five,
so you're going to have an increase in output
based on this very simple model of $500 billion.
So, our multiplier here was five.
But let's say we go the other way,
let's say instead, the government decides
to decrease taxes by a hundred billion dollars.
So, decrease taxes
by $100 billion, and we're gonna assume
the exact same marginal propensity to consume.
Well, in that situation, what's our tax multiplier?
And we're decreasing taxes,
so that will offset this negative.
So, the increase in the economy
is going to be our hundred billion dollars
times our marginal propensity to consume, 0.8,
divided by one minus the marginal propensity to consume.
Well, this part right over here
was exactly the same as what we had over there,
so that's going to be equal to $500 billion,
this part, times 0.8.
And so, what is that going to be?
Well, that is going to be equal to $400 billion.
And once again, intuitively, where did this come from?
Well, if the government spends that hundred billion dollars,
that hundred billion dollars gets spent
and then you have the marginal propensity to consume,
the person or the people who get it
will then spend 80 billion of that,
and then the people who'd get that
would spend 64 billion, on and on and on,
so it eventually ends up being $500 billion.
But with the decrease in taxes of a hundred billion,
that first hundred billion doesn't necessarily get spent.
If I get my taxes reduced, let's say they're all on me,
by a hundred billion, I might save some of it
based on this marginal propensity to consume.
I might save 20 billion of it
and spend the other 80 billion,
and so that's why based on this simplified model,
you might have a lower total impact right over here.
So, that's a very important takeaway.
Fiscal policy, government spending or taxation,
but based on these models,
you would use a different multiplier,
and so they are not going to be necessarily equivalent.