9. The macroeconomy

The multiplier is the ratio of the final change in national income to the initial change in autonomous spending. Each round of extra income creates further spending, but leakages through saving, taxation and imports limit the total.

In a simple model, a higher marginal propensity to consume produces a larger multiplier. The actual effect also depends on spare capacity, prices, interest rates, supply and whether spending crowds out other demand.

If the marginal propensity to consume is 0.75 and the simple closed-economy multiplier is 1/(1−0.75)=4, an initial $10 increase in investment could raise equilibrium income by up to$40 in the stylised model.

The multiplier is not an automatic promise that GDP rises by the textbook number; assumptions and supply constraints matter.

Aggregate demand (AD) is total planned expenditure on domestically produced final goods and services: AD = C + I + G + (X − M). Consumption, investment, government spending and net exports are its components.

Each component has its own determinants: income and confidence affect consumption, interest rates and expectations affect investment, policy affects government spending, and foreign income, prices and exchange rates affect exports and imports.

If C=500, I=120, G=180, X=90 and M=110, AD is 780. Imports are subtracted because they are spending on foreign output.

AD is a flow of planned spending, not the same as GDP in every disequilibrium period, and imports are not added just because they are purchases.

National income is the income generated by production in an economy. In principle, the output, expenditure and income approaches give the same total because one person’s spending is another’s income and output is the corresponding product.

In practice, inventories, informal activity, timing, valuation, depreciation and statistical error create gaps. GDP measures domestic production; GNI adjusts for net factor income from abroad, so the distinction matters for economies with large cross-border income flows.

A firm’s sale is expenditure for the buyer, revenue and factor income for workers and owners, and part of measured output. If stock is produced but unsold, inventory investment prevents the output from disappearing from the expenditure measure.

The accounting identity does not mean every household’s income equals its consumption, and measured national income is not a complete welfare index.

Actual economic growth is a rise in current real output. Potential growth is a rise in productive capacity or the sustainable level of output.

Actual growth can occur when firms use spare capacity and may reverse in a downturn. Potential growth usually requires more resources, better productivity or technology and can support higher output without the same inflation pressure.

A factory reopening idle machines creates actual growth toward capacity; new automation that raises the maximum sustainable output creates potential growth.

A temporary demand boom is not automatically long-run growth, and potential growth does not guarantee actual output rises if demand is weak.

The output gap is the difference between actual real GDP and estimated potential GDP, often expressed as a percentage of potential. A negative gap indicates spare capacity; a positive gap indicates output above sustainable capacity.

Potential output is not directly observed, so the gap is an estimate and can be revised. A negative gap often accompanies unemployment and weak inflation pressure; a positive gap may accompany bottlenecks and demand-pull inflation.

If actual GDP is 980 and potential GDP is 1,000, the output gap is −2% of potential. The number is not a precise count of unemployed people.

An output gap is not simply the GDP growth rate, and a zero estimated gap does not prove every resource is fully employed.

The business cycle is the pattern of expansions and contractions in economic activity around a longer-run trend. Phases may include recovery, expansion, peak, slowdown and recession, but the labels are conventions.

Demand, financial conditions, confidence, inventories, external shocks and policy can amplify cycles. A recession is a period of falling or unusually weak activity; it is not defined solely by one fixed rule in every context.

A credit boom raises spending and employment, then a financial shock cuts investment and demand, creating a downturn below the trend path.

The cycle is not perfectly regular or predictable, and a short slowdown need not meet every definition of recession.

Policies for growth include expansionary fiscal or monetary policy to raise actual output in the short run, and supply-side measures to raise potential output in the long run.

The best mix depends on the output gap, inflation, debt, external balance and the binding constraint. Public investment can affect both AD and LRAS; education takes time but may improve productivity.

During a deep recession, infrastructure spending can use idle labour now and expand transport capacity later. Near full capacity, the same spending may mainly raise prices unless supply expands.

No policy creates costless growth: evaluate financing, implementation lags, distribution, environmental effects and whether demand or capacity is the constraint.

Inclusive growth is growth that improves opportunities and living standards broadly, especially for groups or regions otherwise excluded from productive participation.

It can involve access to education, health, finance, infrastructure, decent work and anti-discrimination, not just redistribution after growth occurs. Measure both aggregate output and who gains, over what time horizon.

A transport link plus vocational training can connect a neglected region to jobs and markets; a national GDP increase concentrated in one city is growth but not necessarily inclusive.

Inclusive does not mean every person receives the same income, and a transfer alone may not remove the structural barrier causing exclusion.

Sustainable economic growth increases current welfare while preserving the environmental, social and physical resources needed by future generations.

Growth can be more sustainable when productivity, clean technology, resource efficiency and institutions reduce emissions and depletion. A single GDP measure does not capture external costs, resilience or distribution.

Investment in renewable power and energy efficiency may raise current demand and future productive capacity while lowering emissions, although materials, land use and reliability still need assessment.

“Green” or “sustainable” is not guaranteed by a label; compare the full life-cycle costs, rebound effects and whether damage is actually reduced.

Full employment is the level of employment consistent with the economy’s normal or sustainable unemployment, so frictional and some structural unemployment may remain.

The term is a benchmark, not a claim that every person has a job immediately. It depends on definitions, labour-market matching, participation and the time horizon.

A worker changing jobs may be temporarily unemployed while the economy is at full employment; a recession that leaves many workers idle creates a negative output gap below the benchmark.

Full employment is not 100% employment, and a low unemployment rate can still hide inactivity, underemployment or poor job quality.

Equilibrium unemployment is consistent with the prevailing wage and labour-market structure: people are searching or changing jobs while vacancies and workers are being matched. Disequilibrium unemployment occurs when the wage or conditions prevent the quantity of labour supplied from matching demand.

A wage floor above the market-clearing level can create excess supply. A recession can also create unemployment through weak demand, even if wages could adjust.

A graduate between suitable offers may be equilibrium unemployment. A binding minimum wage that leaves more applicants than vacancies creates a disequilibrium gap in the simple model.

The labels are about the cause and adjustment mechanism, not whether the unemployed person is trying hard enough.

Voluntary unemployment refers to choosing not to accept available work at the prevailing terms; involuntary unemployment refers to being willing and able to work but unable to find a job at those terms.

The classification depends on the relevant wage, location, hours, skills and working conditions. A person refusing one unsuitable job is not automatically voluntary unemployed if no reasonable job is available.

A worker who rejects a vacancy far below their reservation wage may be described as voluntary under a simple model; a qualified worker seeking jobs at the prevailing wage but finding none is involuntarily unemployed.

“Voluntary” is not a moral judgement and cannot be inferred from a person’s unemployment alone; state the available alternative and the definition used.

The natural rate of unemployment is the rate consistent with stable inflation and normal labour-market matching, usually including frictional and structural unemployment but excluding cyclical unemployment.

It can change when skills, benefits, search technology, demographics, regulation or the structure of industries changes. It is estimated rather than directly observed and can move over time.

Better matching technology may reduce frictional unemployment and lower the natural rate; a permanent decline in a region’s main industry may raise structural unemployment and the rate.

Natural does not mean inevitable or desirable, and it is not the same as a fixed unemployment target or zero inflation in every model.

Employment trends describe how the number, type and quality of jobs change over time. They are shaped by labour-force participation, sectoral demand, technology, trade, demographics, institutions and the business cycle.

A fall in employment in one sector can coexist with overall employment growth if new sectors expand. Distinguish the number of jobs from hours, productivity, pay, security and who can access them.

Automation may reduce routine manufacturing jobs while raising demand for maintenance and design; the net employment effect depends on product demand, retraining and the speed of adjustment.

A rising employment rate does not prove every group benefits, and technological change is not automatically job-destroying or job-creating.

Geographical mobility is the ability to move between locations; occupational mobility is the ability to move between jobs or industries. Skills, housing, transport, family ties, immigration rules and information affect both.

High mobility helps labour markets match vacancies and can reduce structural unemployment, but moving has costs and may harm communities losing workers. Training raises occupational mobility only when it matches real opportunities.

A worker may be qualified for a vacancy but unable to relocate because housing is unaffordable; a short course may help occupational movement if employers recognise the skill.

Mobility is not simply willingness to move, and more mobility is not always socially costless or equally available to all workers.

Policies include demand management for cyclical unemployment, training and mobility support for structural unemployment, job-search services for frictional unemployment, and measures affecting participation or incentives.

Expansionary fiscal or monetary policy can raise employment when demand is weak but may cause inflation or debt. Supply-side measures take longer and may not help a recession caused by missing demand.

A recession may call for temporary demand support; a region losing its main industry may need retraining, transport and relocation support instead.

No unemployment policy works for every type, and reducing the measured rate by changing eligibility is not the same as creating productive jobs.

Money performs four functions: medium of exchange, unit of account, store of value and standard of deferred payment. Good money is durable, portable, divisible, recognisable and scarce enough to retain confidence.

Using money avoids the double coincidence of wants required by barter and provides a common way to compare prices. Inflation weakens its store-of-value function; instability weakens willingness to accept it.

A phone payment lets a seller accept value without wanting the buyer’s particular goods, and the price label provides a unit of account for comparing alternatives.

Money is not identical to income or wealth, and an asset is not automatically money unless it is readily accepted for transactions.

The money supply is the quantity of money in circulation or in relevant bank accounts, depending on the measure used. Narrow measures contain highly liquid cash and deposits; broader measures include less liquid assets.

Credit creation, bank lending, central-bank operations, government balances and public preferences can change the measured supply. The definition and boundary of the monetary aggregate must be stated.

A bank loan credits a borrower’s deposit, increasing spendable bank money, while a repayment can destroy that deposit money. The central bank’s reserve balance is not identical to household money.

The money supply is not just notes and coins, and a larger monetary aggregate does not mechanically create the same increase in real output.

The quantity equation is MV = PY: money supply times velocity equals the price level times real output. It becomes a theory of inflation only when assumptions about velocity and real output are made.

If velocity is stable and real output is determined by real factors in the long run, a sustained increase in money can raise the price level. In the short run, velocity, spare capacity and expectations may change.

If M rises 5%, V and Y are unchanged, the equation implies P rises about 5%. If banks hoard liquidity or output responds, the price effect is different.

MV=PY is an identity in measured data; the causal claim that money causes proportional inflation needs the additional assumptions.

Commercial banks accept deposits, make loans, facilitate payments and provide other financial services. They transform short-term liquid liabilities into longer-term, less liquid assets and earn income from the spread and fees.

Banks face credit, liquidity, interest-rate and operational risks. Capital requirements, reserves, collateral and confidence constrain lending; a bank cannot safely lend every deposited dollar indefinitely.

A bank may fund a five-year business loan with a mixture of deposits and longer-term finance, but must still meet withdrawals and absorb defaults.

Banks are not simply passive intermediaries transferring pre-existing savings, and a loan creates a deposit but also creates a liability for the borrower.

The money supply can expand when banks create new deposits through lending or when central-bank and government operations add liquidity; it can contract through repayment, asset sales, tighter lending or withdrawal of deposits.

The simple money-multiplier story is conditional: banks may hold excess reserves, borrowers may not want loans, and households may change cash preferences. Capital regulation and risk appetite matter as much as reserve availability.

A central-bank asset purchase may increase bank reserves, but if firms are pessimistic and banks tighten standards, deposit creation and spending may rise little.

A reserve injection is not the same as a guaranteed multiple increase in broad money, and money growth need not translate one-for-one into real GDP.

Demand-pull inflation can be restrained by contractionary fiscal or monetary policy; cost-push inflation may require supply-side action, targeted support or acceptance of a temporary price rise.

Policies work through different lags and side effects. Higher rates can reduce demand but increase debt-service costs; taxes can reduce spending but affect incentives; supply improvements take time and may not lower prices immediately.

If inflation follows an overheated demand boom, rate rises may be appropriate. If it follows a one-off energy shock, aggressive demand reduction may cut output while leaving the initial energy price unchanged.

No anti-inflation policy is costless or guaranteed, and a lower inflation rate is not the same as falling prices.

The demand for money is the amount of money people wish to hold rather than spend or invest. Transaction and precautionary motives generally rise with income; speculative demand depends on expected interest rates and asset prices.

Holding money has a liquidity benefit but an opportunity cost: the interest that could have been earned on bonds or other assets. Uncertainty, payment technology and confidence also affect the demand.

A household may hold more cash before a large bill, while an investor may hold liquid funds when expecting bond prices to fall and interest rates to rise.

Money demand is not the same as demand for goods, and a higher income does not necessarily raise every component by the same amount.

An interest rate is the price of borrowing or the return to saving. In a money-market model it is determined where money demand meets the available money supply; in a loanable-funds model it balances saving and borrowing demand.

State the model before explaining a shift. A larger money supply can lower the equilibrium rate in a simple liquidity model, while higher investment demand or lower saving can raise the rate in a loanable-funds model.

If the central bank supplies more liquid balances and money demand is unchanged, the market rate may fall, encouraging borrowing; if confidence simultaneously raises investment demand, the net movement is less clear.

“The interest rate” is not one universal number, and the policy rate, market yields and loan rates can differ.