Classifying goods and services
Classifying goods and services: build the core model, apply it to evidence and qualify conclusions where outcomes depend on context.
Section 1.6 · Classification of goods and services
9708 section 1.6; AS Level. Checked against Cambridge's 2026–2028 Version 2 (latest version published December 2025) and 2029 Version 1 (published September 2026). Cambridge states that neither version has significant changes affecting teaching. Always follow the syllabus for the candidate's examination year.
Before you begin
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which pair defines a pure public good?
What you will learn
- Distinguish free goods from private economic goods
- Explain public goods using rivalry and excludability
- Explain merit and demerit goods through imperfect information
Core model and terms
A private economic good is scarce and typically rival and excludable. A public good is non-rival and non-excludable: one person’s use does not substantially reduce others’ use, and excluding non-payers is difficult. These properties can weaken a private seller’s ability to collect payment.
Apply and evaluate
Merit goods may be under-consumed and demerit goods over-consumed when consumers have imperfect information about benefits or costs. These are not the same classifications as public and private goods; classify the information problem and use characteristics, not the label alone.
Pause and explain
Which statement best applies classifying goods and services?
Worked example
Explain why a city may provide street lighting even when residents cannot be charged per use.
Show the worked solution
- Lighting is shared and non-rival
- Excluding non-payers is difficult
- A private seller may not recover the full social benefit
Answer Lighting is shared and non-rival → Excluding non-payers is difficult → A private seller may not recover the full social benefit
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Explain why a city may provide street lighting even when residents cannot be charged per use.
Give me a hint
Identify the relevant idea in classifying goods and services, then trace the economic chain.
Compare my reasoning
- Lighting is shared and non-rival
- Excluding non-payers is difficult
- A private seller may not recover the full social benefit
Lighting is shared and non-rival Excluding non-payers is difficult A private seller may not recover the full social benefit
Look for these in your work
- Lighting is shared and non-rival
- Excluding non-payers is difficult
- A private seller may not recover the full social benefit
A vaccination protects a patient and reduces disease transmission to others. Identify the relevant classification issue.
Give me a hint
Separate the private benefit from the effect on third parties.
Compare my reasoning
- The patient receives a private benefit
- Others receive an external benefit
- Imperfect information may also reduce uptake
The patient receives a private benefit Others receive an external benefit Imperfect information may also reduce uptake
Look for these in your work
- The patient receives a private benefit
- Others receive an external benefit
- Imperfect information may also reduce uptake
A park charges entry but one visitor does not use up the whole park. Is it automatically a pure public good?
Give me a hint
Check both rivalry and exclusion.
Compare my reasoning
- Entry fees can exclude non-payers
- Crowding can make use rival
- It may not satisfy both public-good conditions
Entry fees can exclude non-payers Crowding can make use rival It may not satisfy both public-good conditions
Look for these in your work
- Entry fees can exclude non-payers
- Crowding can make use rival
- It may not satisfy both public-good conditions
A consumer underestimates long-term harm from a product. Explain why the merit/demerit distinction may matter.
Give me a hint
Trace the information gap to the consumption decision.
Compare my reasoning
- Consumers may not perceive full costs
- Demand can exceed the informed choice
- Information or other policy may be considered
Consumers may not perceive full costs Demand can exceed the informed choice Information or other policy may be considered
Look for these in your work
- Consumers may not perceive full costs
- Demand can exceed the informed choice
- Information or other policy may be considered
Common mistakes
- Treating merit goods as public goods or claiming every privately sold good is socially efficient.
What can you explain now?
Which pair defines a pure public good?
Compare with the explanation
Non-rival and non-excludable
Both features explain why charging individual users may be difficult.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Before moving on, explain the central idea in classifying goods and services and state one condition that could change its effect.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.