Producing more today does not always expand future productive capacity.
Actual economic growth is an increase in real output over time. Potential growth is an increase in the economy's sustainable productive capacity through improvements in resources, skills, capital, technology or institutions. Higher demand can raise actual output by bringing idle resources into use without immediately expanding capacity. Productive investment may affect both demand now and capacity later. A positive growth rate that becomes smaller still describes rising output; negative growth describes falling output. Neither total growth nor capacity growth alone establishes how gains are distributed or whether wellbeing improves.
- Actual growth
- Actual economic growth means real output rises. Gross domestic product (GDP) measures domestic production; real GDP removes the effect of price changes so we can compare the amount produced. Nominal GDP uses current money prices.
- Potential growth
- Potential growth expands the output the economy can produce on a sustained basis, for example through new equipment, better skills or technology. It differs from simply using existing resources more fully.
- Utilisation
- Utilisation means how much available capacity is being used. Bringing idle machines or workers into production raises actual output without necessarily increasing that capacity.
Output now and capacity later
Level versus rate
Growth slowing from a positive 4% to a positive 2% still means output rises; a negative rate means it falls.
Time horizon
Capital means productive assets such as machinery. Spending on it can raise aggregate demand (AD), planned spending on domestic output, before the equipment starts producing. Capacity gains depend on installation and effective use. Reliable rules and organisations, such as contract-enforcement systems, can also support investment and production.
Evidence needed
Potential output is an estimate of sustained productive capability, not an exact physical ceiling. Environmental sustainability is a separate question about protecting future resources and wellbeing. Check population and who receives the gains as well as total output.
| Measure | Initial | Case A | Case B |
|---|---|---|---|
| Actual output | 100 | 104 | 104 |
| Potential output estimate | 110 | 110 | 115 |
| Actual output change | - | +4% | +4% |
| Potential minus actual | 10 | 6 | 11 |
Worked example: More output, with and without new capacity
Actual-output index rises from 100 to 104. In case A, potential-output index stays at 110. In case B, useful new capital and skills raise potential output from 110 to 115. Both cases start from the same indices.
- These are index numbers, with initial actual output set to 100. Actual output reaches 104 in both cases, a 4% rise; the numbers are not currency amounts.
- In A, more existing capacity is used: potential minus actual output falls from 110 - 100 = 10 to 110 - 104 = 6 index units.
- In B, productive potential expands too. The new difference is 115 - 104 = 11 index units, so actual output remains below the new potential estimate.
- The indices distinguish utilisation from capacity. They do not establish that all workers gain or that a potential-output estimate is an exact hard ceiling.
Watch out for this
Actual and potential growth are just two names for the same output increase.
Actual output can rise through fuller use of unchanged resources. Potential growth requires improved productive capability.
Check your understanding
Output rises because idle equipment is used more fully, while sustainable productive capacity is unchanged. What is shown?
- Potential growth only.
- Actual growth without potential growth in this period.
- A necessary fall in actual output.