Output gaps and uncertain potential
| English | 中文 | Pinyin |
|---|---|---|
| output gap/ˈaʊtpʊt ɡæp/ | 产出缺口 | chǎn chū quē kǒu |
| trend growth | 趋势增长 | qū shì zēng zhǎng |
A decision you can investigate
- Real output can grow rapidly while remaining below potential. A revised capacity estimate can reverse the sign of a reported gap even when measured production is unchanged.
- A growth rate and an output gap 产出缺口 answer different questions.
Build the explanation
- Actual growth measures change in real output over time; the long-run trend growth 趋势增长 rate describes the underlying growth path rather than every cyclical fluctuation. The output gap compares actual output with estimated potential at a date: (actual−potential)/potential×100. A negative gap indicates underuse relative to estimated sustainable capacity, often with cyclical unemployment and weaker demand-driven price pressure. A positive gap indicates output above that benchmark, potentially supported temporarily by overtime or unusually intensive use and associated with bottlenecks and inflationary pressure.
- Potential is sustainable capacity, not an absolute physical ceiling. Gap characteristics are tendencies rather than definitions requiring every observed price or labour indicator to move together. Supply shocks can create inflation alongside spare capacity. A trend-growth estimate must not be confused with a directly observed quantity of unused factories.
Work through the evidence
- Actual real output 480 with estimated potential 500 gives (480−500)/500×100=−4%. Actual 525 against potential 500 gives +5%. Production above estimated sustainable capacity can occur temporarily; it does not refute the definition.
- Now actual output rises 480→500, growth 4.17%, while potential rises 500→520, growth 4%. The final gap is (500−520)/520×100=−3.85%, still negative despite positive actual growth.
- With actual output 520 and potential plausibly between 510 and 530, the gap ranges from +1.96% to −1.89%. The uncertainty interval includes zero: confident sign classification would overstate the evidence.
What is the gap at actual 480 and potential 500?
Divide the shortfall 20 by potential 500.
What does actual growth of 4.17% in the worked case establish?
Actual 500 remains below potential 520.
Potential output is directly observed and never revised.
It is estimated using data and assumptions that can change.
Test the limits
- Potential is unobservable and depends on estimates of capital, sustainable labour use, skills, productivity and non-inflationary resource utilization. Data revisions, structural changes and assumptions about trend filters or production relationships can change it; end-of-series estimates are especially sensitive to future information.
- Distinguish uncertainty about the potential level from uncertainty about its growth rate. Positive growth below trend can widen spare capacity; growth above trend can narrow it without producing a positive gap. Monetary/fiscal decisions based on a mistaken gap can over- or under-stimulate demand. Use employment, wages, capacity surveys and price evidence together while acknowledging that none is a perfect independent measure.
At actual 520 and potential 510–530, what is justified?
The endpoint estimates give positive and negative gaps.
Apply and explain your answer
- Why should an analyst hesitate to call the final uncertainty example a positive output gap?
- The defensible potential range places the gap on either side of zero. Measured actual output alone cannot identify sustainable capacity.
Match the terms to their meanings.
Use each term for its stated economic relationship.
Use the terms precisely
- output gap: Actual real output minus estimated sustainable potential, commonly expressed as a percentage of potential.
- trend growth: The underlying long-run rate of real-output growth distinguished from short-run fluctuations.
Actual real output 480 with estimated potential 500 gives (480−500)/500×100=−4%. Actual 525 against potential 500 gives +5%. Production above estimated sustainable capacity can occur temporarily; it does not refute the definition. Now actual output rises 480→500, growth 4.17%, while potential rises 500→520, growth 4%. The final gap is (500−520)/520×100=−3.85%, still negative despite positive actual growth. With actual output 520 and potential plausibly between 510 and 530, the gap ranges from +1.96% to −1.89%. The uncertainty interval includes zero: confident sign classification would overstate the evidence.
Potential is unobservable and depends on estimates of capital, sustainable labour use, skills, productivity and non-inflationary resource utilization. Data revisions, structural changes and assumptions about trend filters or production relationships can change it; end-of-series estimates are especially sensitive to future information. Distinguish uncertainty about the potential level from uncertainty about its growth rate. Positive growth below trend can widen spare capacity; growth above trend can narrow it without producing a positive gap. Monetary/fiscal decisions based on a mistaken gap can over- or under-stimulate demand. Use employment, wages, capacity surveys and price evidence together while acknowledging that none is a perfect independent measure.
Actual growth measures change in real output over time; the long-run trend growth rate describes the underlying growth path rather than every cyclical fluctuation. The output gap compares actual output with estimated potential at a date: (actual−potential)/potential×100. A negative gap indicates underuse relative to estimated sustainable capacity, often with cyclical unemployment and weaker demand-driven price pressure. A positive gap indicates output above that benchmark, potentially supported temporarily by overtime or unusually intensive use and associated with bottlenecks and inflationary pressure.