What causes the economy to move through booms and recessions?
Describe the phases of the business cycle, explain the causes of cyclical fluctuations including cumulative processes and shocks, and explain how turning points and stabilisers shape the cycle
WACE Year 12 Economics Unit 4 on the business cycle: the expansion, peak, contraction and trough phases, the cumulative multiplier and confidence processes that drive fluctuations, the turning points, and how automatic stabilisers and shocks shape the path of activity.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
Jump to a section
What this dot point is asking
SCSA wants you to describe the phases, explain why the economy oscillates rather than growing smoothly, and identify the forces that create and reverse the cycle. Expect a labelled diagram and a short or extended response linking the cycle to unemployment and inflation.
The phases of the cycle
A standard cycle has four phases:
- Expansion (recovery and boom): output, employment and incomes rise; confidence and investment grow; inflation pressure builds as the economy approaches capacity.
- Peak (upper turning point): activity reaches its maximum; resources are fully stretched and growth can no longer accelerate.
- Contraction (downturn or recession): output and employment fall; if real GDP falls for two consecutive quarters it is commonly called a recession.
- Trough (lower turning point): activity bottoms out before recovery begins.
On a diagram, real GDP is plotted against time as a wave oscillating around an upward-sloping trend line representing the economy's long-run productive capacity.
What drives the fluctuations
The cycle is the result of several reinforcing forces.
- The multiplier process. An initial change in spending generates successive rounds of further spending, amplifying the original change and giving the cycle momentum in both directions.
- Confidence and expectations. Optimistic consumers and firms spend and invest more, fuelling expansion; pessimism causes them to cut back, deepening contraction. These swings are often self-fulfilling.
- Investment and the accelerator. Firms invest heavily when demand is rising and slash investment when it slows, making investment the most volatile component of aggregate demand.
Turning points
The cycle reverses at upper and lower turning points.
- The upper turning point arrives when the economy hits supply constraints (labour shortages, capacity limits, rising inflation) that choke off further growth, often reinforced by central banks raising interest rates to contain inflation.
- The lower turning point arrives when activity falls far enough that automatic stabilisers, lower interest rates, falling prices and eventual replacement spending revive demand.
Shocks and stabilisers
External shocks disturb the cycle. Demand-side shocks include the 2008 Global Financial Crisis; supply-side shocks include the COVID-19 pandemic and oil price spikes. Automatic stabilisers (progressive taxation and unemployment benefits) dampen the cycle by withdrawing demand in booms and supporting it in downturns without any policy decision.
Australia's cycle in context
Australia experienced an unusually long expansion of nearly three decades from 1991 until the COVID-19 recession of 2020, the longest run without a technical recession in the developed world. The 2020 contraction was a sharp, pandemic-driven supply-and-demand shock, followed by a rapid policy-supported recovery. This history is useful evidence in extended responses on the cycle and stabilisation policy.