Economics 9708/33 — May/June 2015

Background Concept

Economic efficiency is a central concept in welfare economics. It is often defined in terms of allocative efficiency (producing the mix of goods most desired by consumers) and productive efficiency (producing at minimum cost). The ultimate condition for allocative efficiency is Pareto optimality: a state where no reallocation of resources can make one individual better off without making another worse off. This is the benchmark for evaluating resource allocation.

Understanding the Question

The question asks for the condition under which economic efficiency is achieved in an economy. It presents four alternative statements. The correct statement is the one that captures the essence of Pareto efficiency. The other options are plausible distractors that relate to other macroeconomic concepts but are not definitions of efficiency.

Approach

Recognise that the question is testing the definition of Pareto optimality. Eliminate options that are not definitions of efficiency: B is about unemployment, C about social costs (related to externalities but not efficiency per se), D about growth. The correct answer is A.

Step-by-Step Reasoning

• Option A: "when nobody can become better off without somebody else becoming worse off" – this is the exact definition of Pareto optimality, a condition for allocative efficiency. Hence correct.
• Option B: "when the economy is operating at its natural rate of unemployment" – this refers to the long-run equilibrium where there is only frictional and structural unemployment, but it does not ensure efficiency; there could be inefficiencies elsewhere.
• Option C: "when the level of social costs is minimised" – minimising social costs is desirable but it is not the definition of efficiency; it is more about internalising externalities. Efficiency requires that marginal social benefit equals marginal social cost, not just minimising costs.
• Option D: "when the rate of economic growth is maximised" – growth can occur with inefficiency, and efficiency does not guarantee maximum growth; it is a separate objective.

Thus, only A correctly defines economic efficiency.

Key Takeaways

• Pareto optimality is the standard notion of efficiency in economics.
• Efficiency is about the allocation of resources, not about other macroeconomic objectives like low unemployment, minimised costs, or high growth.
• In multiple-choice questions, it is important to identify the exact definition.

Common Mistakes

• Confusing efficiency with equity or other outcomes.
• Thinking that minimising social costs is the same as efficiency – but efficiency requires that benefits are considered too.
• Choosing the natural rate of unemployment because it sounds like "efficient" in a labour market context, but it is not a general condition.

Things to Be Careful About

• Read the options carefully; the wording of A is precise.
• Do not overthink: the question is a straightforward test of the definition.