Macroeconomics Study Guide

📖 Core Concepts Macroeconomics – study of the whole economy (output, unemployment, inflation) and aggregate policies. Aggregate demand (AD) – total spending on domestic goods at each price level; slopes down because of real‑balance, interest‑rate, and net‑export effects. Aggregate supply (AS) – relationship between output and the price level; horizontal when there is excess capacity, steep/vertical near full‑employment. IS‑LM model – captures equilibrium in goods (IS) and money (LM) markets; shows how fiscal and monetary policies shift output and interest rates. GDP (expenditure approach) – $GDP = C + I + G + (X-M)$; measures total market‑value of final goods and services. Unemployment types – cyclical (business‑cycle driven) vs. structural/natural (medium‑run equilibrium). Inflation – sustained rise in the general price level; measured by price indexes and the GDP deflator. Monetary policy – central‑bank actions (interest‑rate changes, open‑market ops) to influence aggregate demand, inflation, and output. Fiscal policy – government spending and taxation decisions that directly affect aggregate demand. --- 📌 Must Remember Three core macro variables: output, unemployment, inflation. Okun’s Law: ≈ 3 % ↑ output → 1 % ↓ unemployment. Quantity Theory of Money: $MV = PY$ → money‑supply growth ≈ inflation rate (if $V$ constant). GDP Deflator: $ \text{Deflator} = \frac{\text{Nominal GDP}}{\text{Real GDP}}\times100$. 100 = no inflation. Money multiplier: $m = \frac{1}{\text{reserve‑requirement ratio}}$. Fiscal multiplier: Government spending → $ \Delta Y = \frac{1}{1-MPC} \Delta G$ (ignoring crowding out). Policy lag hierarchy: monetary policy → shorter inside/outside lag than fiscal policy. Inflation target: ≈ 2 % (medium‑term). AD slope drivers: Real‑balance (Pigou) effect Interest‑rate (Keynes) effect Net‑export effect --- 🔄 Key Processes Calculating GDP (expenditure): Add $C$, $I$, $G$, and net exports $(X-M)$. Monetary transmission: Central bank changes policy rate → affects borrowing costs → shifts investment & consumption → moves IS curve → changes output & inflation. Fiscal expansion (gap closure): Identify output gap → increase $G$ or cut taxes → shift AD right → raise output toward potential, watch for crowding‑out. IS‑LM analysis of a policy: Fiscal expansion → IS shifts right (higher Y for any r). Monetary easing → LM shifts down/right (lower r for any Y). AD‑AS equilibrium adjustment: AD rightward shift → higher Y & P if AS steep; if AS horizontal, Y rises with little price change. --- 🔍 Key Comparisons Cyclical vs. Structural Unemployment Cyclical: follows business cycle, vanishes at potential output. Structural: natural rate, persists even when economy is at potential. Fixed vs. Flexible Exchange‑Rate Regimes Fixed: currency pegged; monetary policy constrained, fiscal policy primary stabilizer. Flexible: currency floats; monetary policy can target inflation via interest rates. Operation Twist vs. Traditional QE Operation Twist: sells short‑term bonds, buys long‑term bonds to flatten yield curve. QE: purchases large amounts of assets to inject liquidity and lower overall rates. --- ⚠️ Common Misunderstandings GDP ≠ GNI – GNI adds net factor income from abroad; GDP is domestic production only. “Money supply drives inflation” – only true if velocity is stable; other factors (supply shocks) can dominate. LM curve always upward sloping – modern central banks set the policy rate, effectively making LM horizontal at the chosen rate. Crowding‑out is always full – often only partial; depends on slack in the economy and interest‑rate response. --- 🧠 Mental Models / Intuition “Aggregate‑demand curve is a slope of three effects” – picture price falling → wallets feel richer (real‑balance) → banks need less cash (interest‑rate) → exports become cheaper (net‑export). “IS curve as a seesaw” – higher output raises saving → need lower interest to keep investment up; think of a balance between saving (left) and investment (right). “Money multiplier as a lever” – the smaller the reserve ratio, the larger the lever (more deposits created per unit of reserves). --- 🚩 Exceptions & Edge Cases Liquidity trap: When nominal rates ≈ 0, monetary policy loses potency; fiscal policy becomes dominant. Supply‑side inflation: Cost‑push shocks (e.g., oil price spikes) raise prices independent of demand; AD‑AS model predicts leftward AS shift. Zero‑lower‑bound QE vs. Operation Twist: QE expands the balance sheet; Operation Twist reshapes the yield curve without expanding total assets. --- 📍 When to Use Which Choose AD‑AS when analyzing price‑level outcomes and long‑run growth (capacity, shocks). Use IS‑LM for short‑run policy interaction (fiscal vs. monetary) and interest‑rate effects. Apply Quantity Theory when focusing on money‑supply growth as the primary driver of inflation (stable velocity). Prefer Operation Twist to target long‑term borrowing costs without altering overall liquidity. --- 👀 Patterns to Recognize AD right shift + horizontal AS → output rises, little inflation (output gap closing). AD right shift + steep AS → price level jumps, output barely moves (economy near full‑employment). Fiscal expansion + high interest rates → possible crowding‑out (look for LM shift upward). Rising inflation expectations → self‑fulfilling spiral; watch for Phillips‑curve trade‑off signals. --- 🗂️ Exam Traps Distractor: “GDP deflator > 100 means real GDP is higher than nominal.” – Wrong; >100 simply indicates price level rose above the base year. Near‑miss: Claiming that “all unemployment is cyclical.” – Incorrect; structural (natural) unemployment exists even at potential output. Confusing $M1$ vs. $M2$ – $M2$ = $M1$ + time deposits, savings, MMFs; $M1$ does not include these. Misreading Operation Twist: Thinking it “creates new money.” – It merely reallocates existing reserves to flatten the curve. Assuming LM always shifts with monetary policy: Modern frameworks hold the policy rate constant, making LM horizontal; the shift is represented by a move of the interest‑rate axis, not the curve itself.