Position on the PPC
Definition
Productive efficiency: a situation in which an economy produces on its production possibility curve, using all resources fully so that more of one good can be made only by making less of the other.
- Where an economy produces relative to its PPC reveals how well it is using its resources.
- A chosen output can lie on the curve, inside the curve or beyond the curve.
- Each of these positions carries a different economic meaning.
Key Idea
- A point on the curve shows productive efficiency and full employment of resources.
- A point inside the curve shows spare capacity and unemployed or misallocated resources.
- A point beyond the curve is currently unattainable.
On the curve
- A point on the curve means all resources are fully and efficiently employed.
- Output of one good can rise only if output of the other falls, so an opportunity cost is unavoidable.
- This is the position of productive efficiency, though it says nothing about whether the mix produced is the one society most wants.
Inside the curve
- A point inside the curve means some resources are idle or used inefficiently.
- This spare capacity is often linked to unemployment or to a recession, such as the sharp fall in output during the 2008 financial crisis when factories stood idle.
- Output of both goods could rise together simply by putting the idle resources to work, so there is no opportunity cost of the recovery itself.
Example
- Suppose an economy could produce 100 units of good X and 100 units of good Y on its curve.
- Because of unemployment it actually produces only 70 of each — a point inside the curve, 30% below capacity.
- Employing the idle resources could raise output back to the curve (+30 of each) with no sacrifice of either good.
Beyond the curve
- A point beyond the curve lies outside the current boundary of production.
- It cannot be reached with today's resources and technology, however they are allocated.
- It becomes attainable only if the curve shifts outward through economic growth.
Note
- Moving from inside the curve to the curve raises output with no opportunity cost, because idle resources are used.
- Moving along the curve does carry an opportunity cost, because resources must be reallocated from one good to the other.
Why position matters
- The position shows whether an economy is wasting resources or using them fully.
- It links directly to unemployment, spare capacity and the phase of the trade cycle.
- It guides policy, since an economy inside its curve can raise output without the sacrifice needed by one already on it — so the right response depends on which position the economy is in.
Exam technique
- Identify whether a point is on, inside or beyond the curve before analysing it.
- Link a point inside the curve to unemployment or spare capacity.
- Explain that reaching a point beyond the curve needs an outward shift, not reallocation.
Common Mistake
- Do not treat productive efficiency as meaning the best mix of goods for society.
- It only means resources are fully used, not that the right goods are being made.
- Do not confuse using spare capacity with economic growth.
- A move to the curve uses idle resources, while growth shifts the curve outward.
Self review
- What does a point on the curve represent?
- What does a point inside the curve represent?
- Why can output of both goods rise from a point inside the curve?
- What must happen for a point beyond the curve to become attainable?
- What does productive efficiency mean?
