What is an output gap and how do you show it on an AD AS diagram

• →An output gap exists when an economy's actual real GDP diverges from its potential output, the level of output consistent with stable inflation that an economy can sustain over the long run.
• →A negative output gap arises when actual GDP falls below potential GDP, meaning productive resources such as labour and capital are underutilised. This means that unemployment rises above its natural rate and firms operate below full capacity.
• →A positive output gap, occurs when actual GDP exceeds potential GDP, typically because aggregate demand has expanded rapidly, e.g, during a sustained credit boom such as the period preceding the 2008 financial crisis in the UK. As a result, inflationary pressure builds as firms struggle to expand output further and begin to bid up wages and input prices.
• →The output gap is a key indicator of where an economy sits within the economic cycle: a negative gap signals recessionary conditions, while a positive gap signals an overheating economy. The size of the gap influences monetary and fiscal policy decisions, as policymakers attempt to return actual output to its trend level without generating excessive inflation or unemployment.

• →Potential output (trend GDP) is the level of real output an economy can produce when all factors of production are employed at their normal rates — it grows over time as productive capacity expands through capital investment and improvements in technology.
• →Actual GDP fluctuates around trend GDP over the economic cycle; when actual growth persistently exceeds trend growth, a positive output gap opens; when actual growth falls short of trend growth, a negative output gap widens.
• →A negative output gap is associated with spare capacity, cyclical unemployment, and downward pressure on wages and prices; a positive output gap is associated with inflationary pressure and labour shortages.
• →Economic shocks can shift an economy between gap positions: a large positive demand shock (such as a sharp rise in consumer confidence or a fiscal stimulus) can move an economy from a negative to a positive output gap, while a supply-side shock (such as new technology raising productive capacity) can widen the negative gap if demand does not keep pace.
• →The output gap cannot be directly observed in data — it must be estimated — which makes it a source of genuine uncertainty for policymakers and economists alike.

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This diagram shows the boundary of an economy's productive potential at a point in time. A negative output gap can be represented as a point operating inside the PPF, where resources are underutilised, while a positive output gap corresponds to temporary production beyond the sustainable frontier. The outward shift of the PPF over time illustrates how trend (potential) output grows, providing the baseline against which actual output is compared when measuring the gap.

This question tests understanding of the economic cycle and the relationship between actual and potential output. It draws on Edexcel spec point 2.5.2.c, which covers the concept of the output gap, and AQA spec point 4.2.3.1 — Economic growth and the economic cycle, which requires students to distinguish between actual growth and trend growth and to explain how their interaction generates positive and negative output gaps. Students are expected to understand the macroeconomic consequences of each type of gap, including their implications for inflation, unemployment, and the appropriate direction of stabilisation policy.

Examined 5 times across AQA and Edexcel since 2017.

The majority of appearances since 2019 have been on AQA at a single-mark multiple-choice level, with the only extended treatment recorded on Edexcel in 2017.

• →Economic Performance (Advanced) — essential context for understanding how GDP data is used to estimate where actual output sits relative to trend, and what that implies for the macroeconomy.
• →Economic Growth — directly relevant because distinguishing between actual growth rates and trend growth rates is the mechanism through which output gaps open and close.