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IAI Actuarial Core Principles · Business Economics

Business Activity, Unemployment and Inflation for IAI CB2

This CB2 chapter covers how output moves over time (the business cycle), why it moves (aggregate demand and supply), and two main costs of instability: unemployment and inflation. You solve questions by naming the shock, shifting the right curve, tracing effects on output, jobs and prices, and stating assumptions.

What this chapter covers

This chapter is about the economy as a whole. It starts with the business cycle and growth, which describe how output rises and falls. It then uses aggregate demand and aggregate supply to explain why those movements happen, and what a demand or supply shock does to output and the price level.

The next topics look at two outcomes that policymakers watch closely. Unemployment covers its types, how it is measured and what causes it. Inflation covers how price indices are built, what drives price rises and who gains or loses. The chapter ends with the Phillips curve, which links the two and asks whether a government can trade one for the other.

This chapter sits inside the macroeconomics part of CB2, which carries the larger syllabus weighting (55%) against microeconomics (40%). It connects forward to government policy, fiscal and monetary tools and the international economy. It also links to CM2, where inflation and interest rates feed into economic modelling, and to CB1, where the economic climate affects company decisions.

Macroeconomics carries more than half of the 2026 CB2 syllabus weighting, and this chapter holds its core ideas. The paper opens with multiple-choice questions and then moves to written questions, so you need both quick recall of definitions and the ability to write a clear, reasoned explanation. Aggregate demand and supply analysis, inflation and unemployment come up again whenever policy, trade or exchange rates are discussed, so a solid grasp here lifts your marks in several other chapters. The pass mark for CB2 is at least 50%, so careful marks on a core chapter matter.

Business activity, unemployment and inflation: topics in the order to study them

  1. 1Business Cycle and Economic GrowthStart here because it defines the phases and measures of output that every later topic refers to.
  2. 2Aggregate Demand and Aggregate SupplyNext, because this model explains the cycle and is the tool you use for unemployment and inflation questions.
  3. 3Unemployment: Types, Measurement and CausesStudy it after the AD-AS model, so you can link job losses to weak demand and to structural causes.
  4. 4Inflation: Measurement, Causes and EffectsTake it next, as demand-pull and cost-push causes use the same AD-AS curves you have just learned.
  5. 5Inflation-Unemployment Trade-off and Phillips CurveFinish with it, because it combines the last two topics and needs both to be clear.

How to prepare Business activity, unemployment and inflation

Treat this chapter as one story: shocks move demand or supply, output and prices respond, and jobs follow. Learn the diagram first, then the definitions and the written explanations.

  1. Read the five topics in the study order and write a one-line summary for each before going deeper.
  2. Practise drawing the AD-AS diagram from memory. Label axes, curves and equilibrium, then shift one curve and mark the new equilibrium.
  3. Make a list of causes for each outcome: demand-pull and cost-push inflation, and cyclical, structural and frictional unemployment. For each cause, note which curve shifts.
  4. Learn how an index is built, including weights and the base year, and practise computing an inflation rate from two index values.
  5. Write short answers to questions such as why inflation can rise while unemployment falls, stating assumptions clearly and linking each step to the diagram.
  6. Attempt past multiple-choice questions under time, then review each wrong answer to find whether it was a definition gap or a diagram error.
  7. In the last week, redo the diagrams and the quick revision points without notes.

Common mistakes in Business activity, unemployment and inflation

  • Confusing a movement along a curve with a shift of the curve.

    Fix: A change in the price level moves you along the AD curve. A change in any other factor, such as spending or costs, shifts the curve. State which one you mean.

  • Mixing up the types of unemployment.

    Fix: Link each type to one cause: job search for frictional, skills or location mismatch for structural, and weak demand for cyclical. Use one example for each.

  • Treating inflation and a high price level as the same thing.

    Fix: Inflation is the rate of change of the price level. Prices can be high while inflation is low.

  • Computing inflation with the wrong base in the formula.

    Fix: Always divide the change by the earlier index value, and check the answer is sensible.

  • Presenting the Phillips curve as a permanent, fixed trade-off.

    Fix: Say the trade-off is a short-run relationship that can shift, for example with expectations or supply shocks, and give the reason.

  • Drawing diagrams without labels or without explaining them in words.

    Fix: Label both axes, curves and equilibria, and add two or three sentences explaining the shift and its effect on output and prices.

Last-day revision: Business activity, unemployment and inflation

  • The business cycle has phases: expansion, peak, contraction and trough; economic growth is the long-run rise in potential output.
  • Aggregate demand is total planned spending in the economy; it is made up of consumption, investment, government spending and net exports.
  • A rise in aggregate demand moves the AD curve right, raising output and the price level in the usual short-run case.
  • A fall in short-run aggregate supply, such as higher input costs, raises prices and cuts output.
  • Frictional unemployment comes from job search, structural from a mismatch of skills or location, and cyclical from weak demand.
  • Natural unemployment is the level when the economy is at full employment, with only frictional and structural unemployment.
  • Unemployment rate = unemployed ÷ labour force × 100, where the labour force is employed plus unemployed.
  • Inflation rate = (new index − old index) ÷ old index × 100.
  • Demand-pull inflation comes from excess demand; cost-push comes from rising costs of production.
  • Unexpected inflation redistributes wealth, for example from lenders to borrowers on fixed-rate loans.
  • The short-run Phillips curve shows a trade-off between inflation and unemployment; it does not necessarily hold in the long run.
  • Supply shocks can raise inflation and unemployment together, which the simple Phillips curve cannot explain.

Business activity, unemployment and inflation practice questions

Business activity, unemployment and inflation in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

Business activity, unemployment and inflation: frequently asked questions

How should I start studying this chapter for CB2?

Begin with the business cycle, then learn the AD-AS model well. Unemployment, inflation and the Phillips curve all use that model, so it is the base of the chapter.

Do I need to memorise formulas for this chapter?

There are few formulas, but you should know the unemployment rate and inflation rate calculations and how a price index is built. Most marks come from clear definitions, diagrams and reasoned explanations.

Is diagram work important in the written questions?

Yes. A clear, labelled AD-AS or Phillips curve diagram with a short explanation is often the quickest way to show your reasoning. Always state which curve shifts and why.

How does this chapter link to other parts of CB2?

It leads directly into government policy, since fiscal and monetary tools aim at output, jobs and prices. It also supports the international economy topics, where exchange rates and trade affect inflation and growth.