AP® Microeconomics · Unit 3 · Topic 3.7
Allocative and Productive Efficiency
Allocative efficiency means price equals marginal cost, so the last unit made is worth exactly what it cost society. Productive efficiency means producing at the lowest point on average total cost. Long-run perfect competition delivers both at once.
Allocative efficiency asks whether the market is making the right amount of a good, not just making it cheaply. It happens when price equals marginal cost. Price measures what the last unit is worth to buyers; marginal cost measures what that last unit costs to produce. When they match, the value society places on one more unit exactly equals the resources used to make it, so nothing is gained by producing more or less. If price exceeds marginal cost, that unit is worth more than it costs, and too little is being made. If marginal cost exceeds price, too much is being made.
Productive efficiency is a narrower idea about how a given quantity gets made. A firm is productively efficient when it produces at the minimum point of its average total cost curve, the cheapest possible cost per unit given its technology. A firm can hit this minimum point while still producing the wrong quantity for the market as a whole. Cheap production and the right amount of production are separate questions, and only one firm structure reliably answers both.
Long-run perfect competition is the case where free entry and exit push price down to the minimum of average total cost. Since firms also set marginal revenue equal to marginal cost, and price equals marginal revenue under perfect competition, price ends up equal to both marginal cost and minimum average total cost at once. That single quantity is both allocatively and productively efficient, which is why the long-run competitive outcome gets treated as the benchmark against which monopoly and other market structures fall short.
Key terms
- Allocative efficiency
- The condition where price equals marginal cost, so the last unit produced is worth exactly what it costs to make.
- Productive efficiency
- The condition where a firm produces at the minimum point of its average total cost curve.
- Marginal cost
- The additional cost of producing one more unit of output.
- Long-run competitive equilibrium
- The state where free entry and exit drive price to equal both marginal cost and minimum average total cost.
Watch it explained
- How it worksHow does price equal to marginal cost mean the last unit was worth exactly what it cost?
- How it worksShow me productive efficiency as production at the very bottom of average total cost.
- Common mistakeWhy isn't a firm producing at lowest cost automatically producing the right quantity?
- Ties togetherHow does long run competitive equilibrium deliver both kinds of efficiency at once?
Check yourself
End of topic.