The Economic Cycle

All market economies experience fluctuations in economic activity over time. These fluctuations — known as the economic cycle (or business cycle) — are a central topic in macroeconomics and have profound implications for government policy, business decision-making, and individual welfare.

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The Four Phases of the Economic Cycle

The economic cycle describes the short-to-medium-term fluctuations of real GDP around its long-run trend rate of growth. There are four commonly identified phases:

Phase	Characteristics	Key Indicators
Boom (expansion peak)	GDP growth above trend, falling unemployment, rising inflation, high consumer and business confidence, possible current account deficit	Unemployment fell to 3.7% in the UK in mid-2022
Recession	Two or more consecutive quarters of negative real GDP growth (commonly used definition), rising unemployment, falling consumer spending, lower inflation or deflation	UK GDP fell by 0.3% and 0.1% in Q3 and Q4 of 2023
Slump (trough/depression)	The lowest point of the cycle, very high unemployment, spare capacity, low or negative inflation, bankruptcies increase	UK unemployment peaked at over 8% in 2011 following the 2008 financial crisis
Recovery (expansion)	GDP begins to rise, unemployment starts to fall, consumer confidence improves, investment picks up	UK recovery from 2013 onwards saw growth of 2–3% per year

Exam Tip: The NBER (National Bureau of Economic Research) in the US does not use the "two consecutive quarters" rule. For AQA purposes, be aware that economists debate the precise definition of a recession. The key point is a significant, sustained decline in economic activity.

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Trend Growth and Output Gaps

Key Definition: The trend rate of growth is the long-run average rate at which an economy's productive potential increases over time, determined by growth in the labour force, capital stock, and productivity.

The trend rate acts as a benchmark. When actual GDP growth is above trend, the economy is in the boom phase; when below, it is in recession or slump.

Output Gaps

An output gap measures the difference between actual GDP and potential GDP (the level of output the economy could produce at full capacity without generating inflationary pressure).

Type	Definition	Implications
Positive output gap	Actual GDP > potential GDP	Economy operating beyond sustainable capacity; upward pressure on wages and prices; demand-pull inflation
Negative output gap	Actual GDP < potential GDP	Spare capacity in the economy; unemployment above the natural rate; downward pressure on inflation

The Office for Budget Responsibility (OBR) estimated that the UK had a negative output gap of approximately 1.5% of GDP in early 2021 due to COVID-19 restrictions, which subsequently closed rapidly as the economy reopened.

Exam Tip: When drawing AD/AS diagrams, a positive output gap occurs when equilibrium output is to the right of the full-employment level of output (Yfe). A negative output gap occurs when equilibrium is to the left of Yfe.

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Causes of the Economic Cycle

Economists disagree about the fundamental causes of economic cycles. The main explanations include:

1. Demand-Side Shocks

Changes in any component of aggregate demand (C, I, G, X − M) can trigger cyclical fluctuations.

• Consumer confidence — if households become pessimistic about future income or job security, they reduce spending, triggering a downturn. John Maynard Keynes (1936) emphasised the role of "animal spirits" — waves of optimism and pessimism that drive investment and consumption decisions beyond what rational calculation would suggest.
• The multiplier-accelerator model — Paul Samuelson (1939) and John Hicks (1950) showed how the interaction of the Keynesian multiplier with the accelerator theory of investment could generate self-reinforcing cycles. An initial increase in autonomous spending is magnified by the multiplier, which then induces further investment (the accelerator), creating a boom. When growth slows, the process goes into reverse.
• Credit cycles — Hyman Minsky (1986) argued that financial stability is inherently destabilising. During good times, banks lend more freely, asset prices rise, and borrowers take on increasingly risky debt. Eventually, a "Minsky moment" triggers a collapse in confidence and a credit crunch, as seen in the 2007–2008 global financial crisis.

2. Supply-Side Shocks

• Oil price shocks — the OPEC oil embargo of 1973 quadrupled oil prices, causing stagflation (simultaneous inflation and recession) across the Western world.
• Pandemic — COVID-19 caused both a supply shock (lockdowns halted production) and a demand shock (consumer spending plummeted), resulting in the sharpest global recession since the 1930s.
• Technological change — Joseph Schumpeter (1942) described "creative destruction" as a process by which new technologies render old industries obsolete, causing short-term disruption but long-term growth.

3. Policy Shocks

• Monetary policy — a rapid increase in interest rates (as seen from the Bank of England in 2022–2023, raising the base rate from 0.1% to 5.25%) can slow the economy and contribute to recession.
• Fiscal policy — the UK's austerity programme from 2010 reduced government spending and is argued by Keynesian economists to have slowed the recovery.

4. External Shocks

• Changes in global demand (e.g., a recession in a major trading partner).
• Geopolitical events (e.g., the Russia-Ukraine conflict in 2022 disrupted energy and food markets).

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The Multiplier Effect