Definitions
G: Government purchases of goods and servicesExamples: Aircraft carriers, national parks, USPS wages(Stuff that would be I if gov’t was a firm)
T: Net taxes = taxes- transfersTransfers: income redistribution, entitlementsExample: social security, AFDC, food stamps, Medicaid
Compare and contrast the two accounts.Rule of thumb: if the gov’t gets something back, then it is G.
T
Note how we compute T: taxes - transfers
Thus, suppose we increase taxes by $50: T increases $50.Suppose we increase AFDC by $30: T decreases $30
T= taxes - transfers = 0 - 30 = -30Suppose we increase taxes on diamonds by $50 and increase AFDC payments $50. T is not affected. ( T = 50 - 50 = 0). Get familiar with these operations; they are tricky but important.
T/ Y
• Income tax revenues increase
• Bigger houses--> more property taxes
• Sales taxes• Excise taxes• Luxury taxes• SS taxes
• Unemployment falls --> Unemp. Ins falls
• AFDC falls• Fewer qualify for
Medicaid• Food stamps fall
If Y goes up, then…..
Thus, T/ Y > 0. We call T/ Y the tax rate.
Thus, taxes >0 and transfers <0 ==> taxes - transfers >0
Disposable Income
Given your income (your paycheck), do you get to decide between C and S for every dollar? You get to spend your NET income, what you get after taxes. Same for the economy as a whole.
YD=Y-T = gross income - net taxes = disposable income
Thus, we need a new MPC: C/ YD
AsideWhy do we lump taxes and transfers together?
On a 1040 tax return, there are various tax credits. For example, this year parents get a $400 credit for children. This is a tax reduction, but can also be viewed as a transfer.
Suppose you get $100 a month from Social Security but pay $150 in SS taxes. Does that mean that you are only paying $50 in SS taxes or does it mean you pay $150 but get $100?
The two views are hard to distinguish, so we lump them together. This is probably how must people behave anyway.
Check
Suppose the government increases the social security benefit. What account is affected? Which way?
Suppose HCFA (Medicare) hires a new economist. What account?
Suppose government increases the pension for armed services retirees. What account?
Computing MPS
Suppose you are given C/ YD. Can you compute the MPS directly?
A: no. We must convert to C/ Y. How to do?Suppose C/ YD=.6, T/ Y=.3
Y
T
YD C
Pick a number for Y (100)
100
100*.3 = 30
100-30 = 70
70 * .6 = 42So C/ Y= 42/100 = .42
(Recall YD=Y-T)
Getting the multiplier...
C/ Y = .42. Suppose I/ Y=.33. Proceed just as before..42 + .33 = .75 ==> mult=4
Note: if you ever get a multiplier of 2.7754, then you probably did something wrong. I’ll give you “nice” ones.
Investment
The last wrinkle in this model.
Suppose you are thinking about buying a car. What are some important considerations?
Yeah, those are good, but what about your choice between“You have done well in Econ 10. Your reward is an interest -free loan to buy a car.”“My name is LegBreaker Malone. I charge 20 percent interest.”Which would you prefer?
The interest rate rWe’ll assume there is one interest rate r for all transactions.
Suppose you are GM trying to decide whether to build a new Saturn plant. (What account would that be?) Do you pay cash for such a transaction? No. Most firms issue bonds (equivalent to taking a loan). How does r affect their decision to invest?If r is high, then investing is more expensive.Will firms be more or less likely to invest as r increases?A: lessI/ r < 0
A storyYou are trying to decide whether to buy a new pizza oven for your pizzeria, and you know the oven will increase your revenue by $250 a month. The oven will last 4 years, the length of time you have to repay the loan. If the oven costs $10,000 then your payments would be...
7% 8% 9% 10% 11%$239.46 $244.13 $248.85 $253.63 $258.46
At 7 percent, you would probably do it. At 11 percent, you wouldn’t.
Check
Suppose C/ YD = . 5, T/ Y=.4, and I/ Y = .2. Find the multiplier.
Why does I/ r have the sign it does? Tell a story.
The new model
r
I
Y
IrIYII
Y
CCYCC
GICD
TSCY
DY
AA
DA
0,0),,(
10),(
m)equilibriu(in
TGdeficit
rrY
TTYTT
TYY
GG
A
A
D
A
01),(
The flow chart
MultiplierY
C
I
S
-(SA)= CA
IA
DA YD
SAT
CAT
YDTTA
IAr
GA
rA
T
Does this part look familiar?
Other points
MultiplierY
C
I
S
-(SA)= CA
IA
DA YD
SAT
CAT
YDTTA
IAr
GA
rA
T
Why is there no G on this side?
What’s the relationship here?TA
= - YDT
Autonomous Induced
Note the three C’s.
Sample Problem
Suppose C/ YD = .6, T/ Y= .2, I/ Y =.32, I/ r= - 40.Suppose CA=10, GA=20, TA=30, r = 2.ComputeMultiplier, total Y, total C, S, I, T
Step one: C/ Y.
Y
T
YD C100
100*.2 = 20
100-20 = 80
80 * .6 = 48
C/ Y=.48
Step Two: Multiplier
D/ Y = C/ Y + I/ Y + G/ Y = .48 + .32 + 0 = .8
Y D1 D20 0
100 80 100DA=20Y=100Y/ DA=5
1/(1-MPS)=1/(1-.8)=1/.2=1/(1/5)=5
Step Three: Run the Model
MultiplierY
C
I
S
-(SA)= CA
IA
DA YD
SAT
CAT
YDTTA
IAr
GA
rA
T
Suppose C/ YD = .6, T/ Y= .2, I/ Y =.32, I/ r= - 40.Suppose CA=10, GA=20, TA=30, r = 2.
-(-10) 10
20
2-80
0
30 -30
-30*.6 = -18
-12
10+20-80+0-18 = -68
5
-340
-340*.2 = -68
-272
-272*.6 -163.2
-108.8
-108.8
Totals
MultiplierY
C
I
S
-(SA)= CA
IA
DA YD
SAT
CAT
YDTTA
IAr
GA
rA
T
-(-10) 10
20
2-80
0
30 -30
-30*.6 = -18
-12
10+20-80+0-18 = -68
5
-340
-340*.2 = -68
-272
-272*.6 -163.2
-108.8
-108.8
Y -340S -10+-12-108.8 -130.8C 10-18-163.2 -171.2I -80-108.8 -188.8T 30-68 -38G 20 20
C+S+T =Y? -340C+I+G =D=Y? -340
Another
Suppose C/ YD = .7, T/ Y= .3, I/ Y =.26, I/ r= - 30.Suppose we want to balance the budget.G=100, T=100
C/ Y = .49Multiplier = 4
Flow chart
MultiplierY
C
I
S
-(SA)= CA
IA
DA YD
SAT
CAT
YDTTA
IAr
GA
rA
T100
100 -100
-70
-30
30
4
120
36
84
31.2
58.8
25.2
total dS -4.8total dC -11.2total dI 31.2total dT 136total dG 100
TOTALS
Deficit falls by 36?I thought we balanced it!
What happened?
Some of the tax hike came out of savings…Thus, overall D increased.This - via the multiplier - created an increase in tax revenue.
Interest Rate
How does the interest rate change?
Alan Greenspan is the chair of the Federal Reserve. The Fed is the bank of banks, or lender of last resort. If Nationsbank needs cash, they call Alan up and get a loan. What interest rate? Federal Funds Rate. Suppose Federal Funds rate goes up. What happens to r?
The FedThe Fed has a two main functions:•bank of banks•monetary policyWe’re focusing more on the second right now. By controlling r (more to come), the Fed-and Greenspan-control the course of the economy. Many say Greenspan is the second most powerful man in America [trivia: he is married to Andrea Mitchell, dated Baba Wawa, and was one of the programmers most to blame for Y2K]. I say maybe higher.
The Fed wants to limit inflation and keep the economy stable.
Another scenario
Suppose Greenspan sees that C= -60. What could he do to keep Y=0?
Suppose C/ YD = .7, T/ Y= .3, I/ Y =.26, I/ r= - 30.
Greenspan’s tool here is the interest rate.
Answer: r = -2
One (well, two) for the roadSuppose C/ YD = .8T/ Y= .25I/ Y =.15I/ r= - 30.
1.You have a 100 budget surplus. Suppose you can either cut taxes 100, raise transfers 100, or increase spending 100. Which has the bigger impact on Y?
2. Suppose Congress increases G by 100 and autonomous C is up 50. Suppose Greenspan raises r by 5. What is the effect on the deficit?