Macroeconomic
Performance
& Policy
GDP, inflation, unemployment, AD/AS model, the multiplier, economic growth, output gaps, and both demand-side and supply-side policy — the complete Unit 2 framework.
Economic Growth — GDP & GNI
| Distinction | Explanation | Why it matters |
|---|---|---|
| Real vs Nominal GDP | Nominal: measured at current prices. Real: adjusted for inflation using a base year price index. | Real GDP needed to compare living standards over time — nominal growth may just reflect rising prices, not more output |
| Total vs Per Capita GDP | Per capita = Total GDP ÷ Population | Per capita accounts for population size — a large economy may have low living standards if population is huge |
| Value vs Volume | Value = price × quantity. Volume measures only quantity changes (real terms). | Volume comparison removes price effects for cross-country comparisons |
Purchasing Power Parities (PPP): Exchange rates that equalise the purchasing power of different currencies by adjusting for price level differences between countries. Used by IMF/World Bank for international comparisons. E.g., $1 buys more in Bangladesh than in Switzerland — PPP-adjusted figures reflect actual living standards better than market exchange rates.
Recession: Two consecutive quarters of negative real GDP growth. Associated with rising unemployment, falling investment, and reduced consumer confidence.
Limitations of GDP as a Living Standards Measure
- Inequality: Average GDP hides distribution — high GDP/capita may mask extreme poverty if wealth concentrated among few (use Gini coefficient alongside)
- Non-market activity: Unpaid domestic work, voluntary work, childcare not counted — underestimates true welfare
- Environmental damage: Pollution-intensive growth boosts GDP but reduces wellbeing — GDP doesn't subtract environmental degradation
- Composition of output: GDP includes military spending, prisons — doesn't distinguish welfare-enhancing from welfare-neutral output
- Informal economy: Black market and subsistence farming not captured — large undercount in developing economies
- Subjective wellbeing: Easterlin Paradox — beyond a threshold, higher income doesn't increase happiness. Bhutan uses Gross National Happiness instead.
Inflation & Deflation
Causes of Inflation
| Type | Cause | Example | Diagram effect |
|---|---|---|---|
| Demand-pull | AD grows faster than AS — economy at or near full capacity | Boom period; large government stimulus; rapid credit expansion | AD shifts right → P rises, Y rises (if below capacity) or mainly P rises (at capacity) |
| Cost-push | Rise in costs of production → SRAS shifts left | Oil price shock (1973, 2022); rising wages; commodity price spike | SRAS shifts left → P rises, Y falls — stagflation risk |
| Money supply (Monetarist) | Excessive growth in money supply — Milton Friedman: "Inflation is always and everywhere a monetary phenomenon" | Post-WWII hyperinflation; Zimbabwe 2008; Quantitative Easing concerns | AD shifts right as money supply ↑ |
Effects of Inflation
| Stakeholder | Effect |
|---|---|
| Consumers (savers) | Purchasing power eroded; real value of savings falls; menu costs (frequent repricing) |
| Consumers (borrowers) | Gain — real value of debt falls; fixed mortgage repayments become easier |
| Firms | Rising costs reduce profits; uncertainty harms investment; export competitiveness falls |
| Workers | Real wages fall if nominal wage rises lag inflation; bracket creep in tax system |
| Government | Tax revenues rise (fiscal drag); real value of government debt falls — helps public finances; but may lose credibility |
| Competitiveness | Higher domestic inflation → exports more expensive → current account deteriorates |
Deflation effects: Consumers delay purchases (wait for lower prices) → AD falls → output falls → unemployment rises → debt-deflation spiral (real debt burden rises). Japan 1990s "Lost Decade" — persistent deflation → prolonged stagnation despite zero interest rates. Very hard to escape once entrenched.
Unemployment
Types & Causes of Unemployment
| Type | Cause | Best policy response |
|---|---|---|
| Frictional | Time between jobs — workers searching, firms recruiting. Always exists in dynamic economies. | Job centres, improved information (Universal Jobmatch); better job matching |
| Seasonal | Demand for labour varies seasonally (tourism, agriculture, construction) | Retraining; tourism diversification; seasonal tax credits |
| Structural | Long-run mismatch between skills demanded and skills available — deindustrialisation, automation, geographic immobility | Retraining programmes; regional policy; investment in education |
| Cyclical (demand-deficient) | Fall in AD during recession → firms reduce workforce. Rises and falls with the economic cycle. | Expansionary fiscal/monetary policy to boost AD |
| Real wage (classical) | Minimum wage or union bargaining keeps wages above market-clearing level → excess supply of labour | Reduce minimum wage (controversial) or improve labour market flexibility |
Effects of Unemployment
- Workers: Loss of income; skills atrophy (hysteresis); mental health damage; social exclusion
- Firms: Smaller labour pool for recovery; loss of consumer demand during recession
- Public finances: Automatic stabilisers — government pays more benefits, receives less tax → deficit rises
- Economy: Output gap (inside PPF); wasted human capital; lower potential growth
- Society: Higher crime rates; family breakdown; regional deprivation spirals
Balance of Payments — Current Account Overview
- Current account deficit: Imports of goods/services exceed exports — more money leaving the country than entering. Typically means borrowing from abroad or selling assets.
- Current account surplus: Exports exceed imports — net creditor position. E.g., Germany, China have persistent surpluses.
Note: Unit 2 requires understanding of current account components and deficit/surplus distinction — in-depth causes and remedies are covered in Unit 4 (IAL A2).
The AD Curve
AD curve slopes downward — at higher price level: real wealth falls (wealth effect), exports become less competitive, interest rates tend to rise reducing consumption and investment.
Movement along AD: Change in price level → movement along existing AD curve (to new equilibrium with AS).
Shift of AD: Change in any component (C, I, G, or net exports) at every price level → entire AD curve shifts left or right.
Consumption (C)
Typically ~60–65% of GDP in developed economies. Key influences:
| Factor | Effect on C | Mechanism |
|---|---|---|
| Disposable income (Keynes) | ↑ income → ↑ C | Higher income → more available to spend after tax/savings |
| Interest rates | ↑ rates → ↓ C | Borrowing costs rise; mortgage costs rise; returns to saving rise (opportunity cost of spending) |
| Consumer confidence | ↑ confidence → ↑ C | Optimistic about future → willing to borrow and spend; less precautionary saving |
| Wealth effects | ↑ asset prices → ↑ C | House price rises → homeowners feel wealthier → spend more (even without realising gain) |
| Credit availability | ↑ credit → ↑ C | Easier to borrow → consumers bring forward future spending |
| Welfare payments | ↑ welfare → ↑ C (for recipients) | Safety net reduces precautionary saving; transfers income to high-MPC households |
Savings ratio: Savings as % of household disposable income. If savings ratio rises, consumption falls (other things equal). Influenced by: interest rates, uncertainty, confidence, age distribution.
Investment (I)
Most volatile component of AD — swings dramatically over business cycle.
Key influences on investment:
- Rate of economic growth (Accelerator effect): Rising output → firms invest to expand capacity. Higher GDP growth → higher investment demand (Jorgenson's accelerator model)
- Interest rates: Lower rates → cheaper to borrow for investment; lower hurdle rate for project viability
- Business confidence/expectations: "Animal spirits" (Keynes) — expectations about future demand drive investment regardless of current conditions
- Availability of credit: Tighter credit conditions (as in 2008–09) → sharp fall in investment even without rate rise
- Corporation tax: Lower tax on profits → higher post-tax returns → more investment
Government Expenditure (G) & Net Trade (X−M)
Government spending: Determined by fiscal policy; level of economic activity (automatic stabilisers — welfare spending rises in recessions); market failure correction (public goods, NHS); political priorities.
Net exports (X−M): Influences:
- Exchange rate: depreciation → exports cheaper (↑X), imports dearer (↓M) → X−M improves (subject to Marshall-Lerner condition — covered in Unit 4)
- Relative inflation rates: higher domestic inflation → exports less competitive
- Global economic conditions: world recession → export demand falls
- Protectionism: tariffs/quotas abroad → reduce X; domestically reduce M
- Non-price competitiveness: quality, innovation, after-sales service
Short-Run Aggregate Supply (SRAS)
Factors Shifting SRAS
- Costs of raw materials/energy: Oil price spike → SRAS shifts left (costs rise → less supplied at each price level). E.g., 1973 OPEC oil shock → SRAS shifted left → stagflation
- Exchange rates: Currency depreciation → imported raw material costs rise → SRAS shifts left
- Tax rates: Rise in employers' NI contributions or corporation tax → production costs rise → SRAS shifts left
- Wages: Unexpected wage increases (above productivity) → unit labour costs rise → SRAS shifts left
Long-Run Aggregate Supply (LRAS)
Classical (Monetarist) LRAS: Vertical at the natural rate of output (Yf — full employment). In the long run, real output is independent of the price level — determined only by supply-side factors. AD changes cause only price level changes in the long run.
Keynesian LRAS: Three-stage shape — flat (spare capacity, no price pressure), upward-sloping (approaching capacity), vertical (full capacity). At high spare capacity, AD increases can boost real output without inflation — justification for fiscal stimulus in deep recessions.
Factors Shifting LRAS (= Productive Potential)
| Factor | How it shifts LRAS |
|---|---|
| Technology improvement | Rightward — same inputs produce more output (TFP growth) |
| Productivity increases | Rightward — workers produce more per hour |
| Education & skills | Rightward — human capital accumulation; higher productivity |
| Government deregulation | Rightward — reduces compliance costs; increases competition → efficiency |
| Net migration (skilled) | Rightward — expands labour force and skills base |
| Capital investment | Rightward — more physical capital → greater productive capacity |
| Competition policy | Rightward — prevents monopoly inefficiency; encourages innovation |
The Circular Flow of Income
Income flows between households and firms in a continuous loop: households provide factor services (labour, land, capital, enterprise) → firms pay factor incomes (wages, rent, interest, profit) → households spend income on goods/services → firms receive revenue. In a closed economy with no government, income = output = expenditure.
Injections (J): Spending flowing INTO the circular flow from outside: Investment (I), Government spending (G), Exports (X).
Withdrawals/Leakages (W): Income flowing OUT of the circular flow: Savings (S), Taxation (T), Imports (M).
Equilibrium: J = W → Injections = Withdrawals → national income stable. If J > W → income rises. If W > J → income falls.
The Multiplier
Marginal propensities:
- MPC (marginal propensity to consume): Fraction of extra income spent on consumption. Higher MPC → larger multiplier.
- MPS (marginal propensity to save): Fraction saved. Higher MPS → smaller multiplier (more leaks out).
- MPT (marginal propensity to tax): Fraction lost to taxation.
- MPM (marginal propensity to import): Fraction spent on imports — leaks out of domestic circular flow.
Example: If MPC = 0.8, MPS = 0.2 → k = 1/0.2 = 5. A £10bn government spending increase → national income rises by £50bn. But in open economies with taxation and imports, MPW is large → multiplier typically <2 in practice.
Actual vs Potential Growth
Causes of Growth
- Actual growth causes: Increases in C, I, G, or net exports → AD shifts right → output rises (if spare capacity available)
- Potential growth causes: Capital investment (Solow growth model — capital accumulation); FDI; innovation and R&D; labour force growth (migration); education and skills; competition policy
- Export-led growth: Rising export demand drives output growth (East Asian Tigers — South Korea, Taiwan, Singapore used export-led development strategies)
Benefits and Costs of Growth
- Higher living standards (more goods/services available)
- Lower unemployment — firms hire more as output rises
- Higher tax revenues → improved public services
- More investment — growth feeds future growth
- Better funded public services (NHS, education)
- Environmental damage — more output → more pollution, resource depletion
- Inequality may rise (Kuznets curve — growth initially worsens inequality)
- Inflation risk if growth exceeds productive capacity
- Current account deficits — growth raises import demand
- Opportunity costs — resources used for production foregone leisure, sustainability
Output Gaps
| Type | Meaning | Associated conditions | Policy response |
|---|---|---|---|
| Negative output gap | Actual GDP < Potential GDP — spare capacity, underemployment | High unemployment, low inflation, weak investment | Expansionary fiscal/monetary policy to stimulate AD |
| Positive output gap | Actual GDP > Potential GDP — economy overheating | Low unemployment, rising inflation, overheating | Contractionary policy — raise interest rates, reduce G |
Difficulties measuring output gaps: Potential GDP is not directly observable — must be estimated using trend growth rates, which change over time. Technological disruption and demographic shifts alter potential output. Policymakers may misjudge — wrongly stimulating an economy that has no slack, causing inflation.
Macroeconomic Objectives
| Objective | Target/Indicator | Why important |
|---|---|---|
| Economic growth | Positive real GDP growth; UK target ~2–2.5%/year | Rising living standards; employment; tax revenues |
| Low, stable inflation | Bank of England target: 2% CPI | Maintains purchasing power; business planning certainty; competitiveness |
| Low unemployment | Full employment ≈ NAIRU (Non-Accelerating Inflation Rate of Unemployment) | Productive capacity; social wellbeing; government finances |
| Current account equilibrium | Sustainable current account position | Avoids unsustainable borrowing from abroad or dependence on foreign capital |
| Balanced budget | Government not running persistent deficit | Avoids mounting public debt; inter-generational equity |
| Income equality | Reduce Gini coefficient; progressive taxation | Social cohesion; merit goods access; political stability |
Conflicts Between Objectives
| Conflict | Mechanism | Example |
|---|---|---|
| Inflation vs Unemployment (Phillips Curve) | Short-run trade-off: lower unemployment → higher AD → higher wage inflation. Expanding AD reduces unemployment but raises inflation. | UK 1960s–70s; expansionary policy worsened inflation without permanent unemployment fall |
| Growth vs Environment | GDP growth → more resource use, emissions, pollution | China's rapid growth alongside severe air/water pollution |
| Growth vs Inflation | Rapid growth beyond productive capacity → demand-pull inflation | Economy growing above trend rate → CPI rises, requires policy tightening |
| Growth vs Equality | Growth may benefit capital owners more than workers — Kuznets inverted-U | US growth 1980s–2000s: real wages stagnated for bottom 50% despite GDP rising |
| Inflation vs Current Account | Higher domestic inflation → exports less competitive → current account worsens | Tightening to reduce inflation raises exchange rate → improves CA but hurts exports |
Demand-Side Policy
Fiscal Policy
- Effective when monetary policy constrained (liquidity trap at zero rates)
- Can be targeted to specific sectors/regions
- Large multiplier if MPC high (target poor households)
- Automatic stabilisers work immediately without political decisions
- Time lags — political/legislative delays before spending implemented
- Crowding out — government borrowing raises interest rates → reduces private investment
- Deficit risk — deficit spending raises national debt → future tax burden
- Political pressures — stimulus hard to reverse; electoral cycle distorts timing
Monetary Policy
| Instrument | How it works | Effect on AD |
|---|---|---|
| Interest rates (Bank Rate) | ↓ rates → cheaper borrowing → ↑C, ↑I; depreciation of £ → ↑X | Expansionary |
| Quantitative Easing (QE) | BoE buys government bonds → injects money supply → lowers long-term yields → ↑asset prices → wealth effect → ↑C | Expansionary (used at zero lower bound 2009–21) |
| Reserve requirements | ↓ reserve ratio → banks lend more → money supply expands → ↑AD | Expansionary |
| Lending criteria | Tightening criteria (post-2008 Basel III) → banks lend less → ↓credit → ↓C, ↓I | Contractionary |
Role of central banks: Implementation of monetary policy (setting interest rates); achieving inflation target (BoE 2% CPI); banker to government (manages national accounts); lender of last resort (emergency liquidity to solvent banks facing short-term cash shortage — Bagehot principle: "lend freely at penalty rate against good collateral").
- Independent central bank — free from electoral cycle; credible commitment
- Quick to implement (MPC meets monthly)
- Works through multiple channels (consumption, investment, exchange rate)
- Automatic — forward guidance shapes expectations before action needed
- Zero lower bound problem — rates can't go below 0% (without unconventional QE)
- Time lags — 18–24 months for full effect of interest rate changes
- Liquidity trap (Keynes) — cuts ineffective if confidence too low to borrow/spend
- Distributional effects — low rates help borrowers, hurt savers
Supply-Side Policies
| Type | Policy | Mechanism | Limitation |
|---|---|---|---|
| Free market (market-oriented) | Deregulation, privatisation, ↓income tax, ↓welfare, cut red tape | Strengthens price incentives; removes barriers to entry; reduces market distortions | May worsen inequality; public goods under-provided; short-term disruption |
| Interventionist | Education investment, training schemes, infrastructure, subsidies to R&D, regional policy | Human capital accumulation; improves factor productivity; addresses market failures in investment | Long time lag (education takes decades); expensive; risk of white elephant projects |
Model Answer
Demand-pull inflation occurs when aggregate demand rises faster than aggregate supply — typically when the economy is at or near full capacity. Excess demand "pulls" prices upward. In an AD/AS diagram, the AD curve shifts right along an upward-sloping SRAS → price level rises alongside real output. Common causes: rapid credit expansion, fiscal stimulus, rising consumer confidence.
Cost-push inflation occurs when production costs rise, shifting the SRAS curve leftward. Firms pass higher costs to consumers through higher prices. Real output falls at the same time as prices rise — this combination is called stagflation (stagnation + inflation). Common causes: oil price shocks (1973 OPEC), sharp wage increases, commodity price spikes, import cost rises from currency depreciation.
Key distinction: demand-pull comes from the demand side (AD ↑); cost-push from the supply side (SRAS ↓). Different policy responses are needed — demand-pull can be addressed by tightening monetary/fiscal policy; cost-push is much harder to address without worsening unemployment.
Model Answer
A rise in interest rates reduces inflation through several transmission channels:
1. Consumption falls: Higher rates → mortgage repayments increase → less disposable income for spending. Variable-rate borrowers (most UK homeowners) see immediate squeeze. Saving becomes more attractive → less consumption at each price level → AD falls.
2. Investment falls: Higher borrowing costs → firms postpone capital projects with lower expected returns → I component of AD falls → further leftward shift in AD.
3. Exchange rate appreciation: Higher UK interest rates attract capital inflows → demand for sterling rises → pound appreciates → exports become more expensive (↓X) and imports cheaper (↑M) → net exports fall → AD shifts further left.
As AD shifts left, output falls toward potential output, removing the positive output gap. Reduced demand pressure → prices rise more slowly → inflation falls toward the 2% target. Transmission takes 18–24 months for full effect, hence the Bank of England must act pre-emptively based on inflation forecasts.
Model Answer
The multiplier describes how an initial injection of spending into the circular flow generates a proportionally larger final increase in national income. If the government spends an additional £10bn on infrastructure, this creates income for construction workers and suppliers. These workers spend a fraction (MPC) of their new income on goods/services → creating income for others → who in turn spend their MPC → and so on. Each round leaks less out than the last (via savings, tax, imports) until the multiplied effect dies out.
Factors determining multiplier size:
MPC: Higher MPC → more of each round re-spent → larger multiplier. Poorer households have higher MPC (less able to save), so fiscal transfers to low-income groups produce a larger multiplier effect.
Openness of economy: High MPM (import propensity) → much of each spending round leaks abroad → small multiplier. Open economies like the UK have multipliers around 0.5–1.5. Closed economies have larger multipliers.
Tax rate: High MPT → more income taxed away each round → smaller multiplier. Progressive taxation automatically limits the multiplier but stabilises fluctuations (automatic stabiliser).
Spare capacity: If economy at full capacity, the multiplier only raises prices (price multiplier) rather than real output. Real multiplier effect largest when large negative output gap exists.