UNIT 5 · SLIDE 1
The Short-Run Phillips Curve
A — boom
B — recession
SRPC
Inflation rate
Unemployment rate
The short-run tradeoff
Low unemployment tends to come with high inflation,
and vice versa — you slide ALONG the curve.
Each SRPC point mirrors an AD/AS equilibrium.
A = inflationary gap · B = recessionary gap
Movements vs. shifts
AD shifts → movement ALONG the SRPC
AD right → up-left (inflation↑, unemployment↓)
AD left → down-right (inflation↓, unemployment↑)
SRAS shifts → the whole SRPC SHIFTS (Slide 2)
Demand moves you along; supply moves the curve.
The SRPC is the AD/AS model in different axes — every gap has a matching Phillips point.
The Review Hub · AP Macroeconomics Unit 5
The SRPC shows the short-run tradeoff: less unemployment, more inflation. AD shifts move you along the curve; supply shocks shift it.
UNIT 5 · SLIDE 2
The Long-Run Phillips Curve
LRPC
SRPC₁
SRPC₂
natural rate
Inflation rate
Vertical at the natural rate
In the long run there is NO tradeoff — unemployment
returns to its natural rate at ANY inflation rate.
LRPC is the LRAS curve in Phillips-space
What shifts the curves
SRPC shifts RIGHT/UP: negative supply shock or
higher inflation expectations (= stagflation)
SRPC shifts LEFT/DOWN: positive supply shock or
lower expectations
LRPC shifts only if the NATURAL RATE changes
(demographics, job-matching efficiency, structural change)
Stagflation = SRPC shifted right — high inflation AND high unemployment at once.
The Review Hub · AP Macroeconomics Unit 5
The LRPC stands vertical at the natural rate — no long-run tradeoff. Supply shocks and inflation expectations shift the SRPC; only changes in the natural rate itself move the LRPC.
UNIT 5 · SLIDE 3
The Quantity Theory of Money
M × V = P × Q
The four letters
M — money supply
V — velocity: times each dollar is spent per year
P — price level
Q — real output (real GDP)
V is stable and Q is fixed by resources in the
long run → any M growth flows straight into P.
Money neutrality (long run)
Doubling the money supply eventually just
doubles prices — real GDP, employment, and the
real interest rate end up UNCHANGED.
Short run: money moves REAL variables (Unit 4)
Long run: money only moves NOMINAL ones
"Inflation is always and everywhere a monetary
phenomenon." — Milton Friedman
Sustained money growth faster than output growth → inflation , one-for-one in the long run.
The Review Hub · AP Macroeconomics Unit 5
MV = PQ. With velocity stable and output fixed by real resources, long-run money growth becomes inflation — and money is neutral : real variables don't change.
UNIT 5 · SLIDE 4
Deficits vs. Debt
Budget DEFICIT — a flow
one year's shortfall
Spending > tax revenue in a single year
Financed by SELLING BONDS (borrowing)
Surplus = the opposite (revenue > spending)
Expansionary fiscal policy usually widens the deficit
National DEBT — a stock
the accumulated total
Sum of ALL past deficits minus surpluses
Grows every year the budget runs a deficit
Requires ongoing interest payments
Interest costs squeeze future budgets
Why economists worry about persistent deficits
Government borrowing competes with private borrowers in the loanable funds market,
pushing real interest rates up and private investment down — crowding out (next slide).
A "flow vs. stock" MCQ shows up almost every year — deficit fills the debt bathtub.
The deficit is the faucet ; the debt is the bathtub it fills year after year.
The Review Hub · AP Macroeconomics Unit 5
Deficit = one year's shortfall (a flow); debt = all accumulated deficits (a stock). Deficits are financed by selling bonds — which is exactly what sets up crowding out.
UNIT 5 · SLIDE 5
Crowding Out
S
D₁
D₂
r₂
r₁
Real interest rate
Loanable funds
The mechanism
Deficit spending → government borrows → demand
for loanable funds shifts RIGHT (D₁ → D₂) →
real interest rate rises (r₁ → r₂) →
private investment spending falls.
Private borrowers get "crowded out" of the market.
The long-run cost
Less investment today → smaller capital stock
tomorrow → slower LRAS / PPC growth.
Stimulus buys output now at the price of some
future growth — the classic policy tradeoff.
FRQ chain: deficit → borrow → D for loanable funds right → real r ↑ → private I ↓ .
The Review Hub · AP Macroeconomics Unit 5
Government borrowing shifts loanable-funds demand right, raising the real rate and squeezing out private investment. The long-run cost: a smaller capital stock and slower growth.
UNIT 5 · SLIDE 6
What Actually Drives Long-Run Growth
Productivity is the engine
Output per worker determines living standards.
Growth = growing productivity, not just more hours.
Its three sources
Physical capital · human capital (education, skills)
· technology. All three raise output per worker.
Pro-growth policies
Incentives for saving & investment, education
funding, R&D support, stable institutions.
How growth shows on graphs
LRAS shifts right = PPC shifts outward =
natural-rate output (Yf) rises over time.
The measure that matters
Economic growth = sustained increase in REAL GDP PER CAPITA
Adjusts for inflation and population — a bigger population alone is not growth in living standards
Policies that boost investment and human capital shift LRAS right — everything else is short-run.
The Review Hub · AP Macroeconomics Unit 5
Long-run growth comes from productivity: physical capital, human capital, and technology. It appears as a rightward LRAS shift (= outward PPC shift) and is measured in real GDP per capita.
UNIT 5 · SLIDE 7
Combining Fiscal & Monetary Policy
Both expansionary
Output: rises strongly (both push AD right)
Interest rate: AMBIGUOUS — fiscal pushes r up,
monetary pushes it down
Classic pandemic-response combo
Both contractionary
Output: falls strongly (both pull AD left)
Interest rate: AMBIGUOUS — opposite pressures
again, in reverse
Used against entrenched inflation
Expansionary fiscal + tight money
Interest rate: rises strongly (both push r up)
Output: AMBIGUOUS — policies pull AD in
opposite directions
Heavy crowding-out pressure on investment
Tight fiscal + easy money
Interest rate: falls strongly (both push r down)
Output: AMBIGUOUS — offsetting AD effects
Investment-friendly mix: low r encourages capital
formation → better long-run growth
Same-direction policies → output certain, r ambiguous · Opposite policies → r certain, output ambiguous
When two policies combine, one variable is always ambiguous — the single most classic Unit 5 MCQ.
The Review Hub · AP Macroeconomics Unit 5
Policy combos: same direction → output effect is certain but the interest rate is ambiguous; opposite directions → the interest rate is certain but output is ambiguous. Memorize the 2×2.
UNIT 5 · SLIDE 8
Unit 5 Quick Reference — Know These Cold
Phillips curves
SRPC: down-sloping · AD moves you ALONG it
Supply shocks & expectations SHIFT it
LRPC: vertical at the natural rate
Stagflation = SRPC shifted right
Money in the long run
MV = PQ · V stable, Q resource-fixed
M growth → proportional P growth (inflation)
Money neutrality: real variables unchanged
Short run ≠ long run — money matters short-run
Deficits, debt & crowding out
Deficit = yearly flow · Debt = accumulated stock
Borrowing → D for funds right → r↑ → private I↓
Long-run cost: smaller capital stock, slower LRAS
Draw it on the loanable funds graph
Growth & policy mix
Growth = productivity: capital, human capital, tech
Measured by real GDP per capita · LRAS right
Policy combos: one variable always ambiguous
Same direction → r ambiguous · opposite → Y ambiguous
Unit 5 is 20–30% of the exam — the heaviest-weighted unit. Phillips curve + crowding out are FRQ staples.
The Review Hub · AP Macroeconomics Unit 5
Phillips curves, money neutrality, deficits vs. debt, crowding out, and growth drivers — Unit 5 carries the biggest exam weight , so drill these until automatic.