Public Goods (DP IB Economics)

Revision Note

Steve Vorster

Written by: Steve Vorster

Reviewed by: Jenna Quinn

Characteristics of Public Goods

  • A public good is substantially different to a private good

  • Private goods are goods which firms are able to provide to generate profits. They can generate profits as these goods are excludable and rivalrous

    • The firm is able to exclude certain customers from purchasing their goods through the use of the price mechanism. If customers cannot afford to buy them, then they are excluded

    • Customers can also compete for these goods which are limited in supply and this rivalry helps to generate profits for firms

  • Public goods are goods that are beneficial to society (e.g. roads, parks, lighthouses, national defence) but which will not be provided by private firms due to the principles of non-excludability and non-rivalry 

    • Non-excludability refers to the inability of private firms to exclude certain customers from using their products. In effect, the price mechanism cannot be used to exclude customers e.g. street lighting

    • Non-rivalry refers to the inability of the product to be used up, so there is no competitive rivalry in consumption to drive up prices and generate profits for firms

    • Therefore, governments will often provide these beneficial goods themselves, and so they are called public goods

  • If firms decided to provide these goods anyway, it would give rise to what is called the ‘free rider’ problem

    • This is a situation where customers realise that they can still access the goods, even without paying for them

    • If they are paying, they stop and continue to enjoy the benefits. They are ‘free-riding’ on the backs of other paying customers

    • Over time, any customers who are paying for the goods will stop

    • At some point firms will cease to provide these goods and they will become under-provided in society

Examiner Tips and Tricks

Make sure that you know the difference between public goods and merit goods. The key idea is that private firms will not provide public goods, so under-provision (or no provision) occurs in society.

On the other hand, private firms will provide some merit goods as they are able to make a profit from them. However, due to the profit incentive and high prices that firms charge, not all members of society will be able to afford these goods. So merit goods are also under-provided, but there is some provision for them.

Government Intervention in Response to Public Goods

  • Governments have three possible responses to the under-provision of public goods

  1. Do nothing:  no provision is offered

  2. Provide the good/service themselves e.g. libraries, parks

  3. Contract out: accept bids from private companies who wish to provide the good/service, choose the lowest priced bid and pay the company to provide the good/service 

  • Both option 2 and 3 require the provision to be paid for by governments

    • There is an opportunity cost to any funding decision

Examiner Tips and Tricks

Government provision is an excellent way to address inequality in society. More government provision usually reduces inequality and less government provision usually increases inequality. Government provision often increases when an economy is booming and reduces when an economy is in recession or struggling. 

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Steve Vorster

Author: Steve Vorster

Expertise: Economics & Business Subject Lead

Steve has taught A Level, GCSE, IGCSE Business and Economics - as well as IBDP Economics and Business Management. He is an IBDP Examiner and IGCSE textbook author. His students regularly achieve 90-100% in their final exams. Steve has been the Assistant Head of Sixth Form for a school in Devon, and Head of Economics at the world's largest International school in Singapore. He loves to create resources which speed up student learning and are easily accessible by all.

Jenna Quinn

Author: Jenna Quinn

Expertise: Head of New Subjects

Jenna studied at Cardiff University before training to become a science teacher at the University of Bath specialising in Biology (although she loves teaching all three sciences at GCSE level!). Teaching is her passion, and with 10 years experience teaching across a wide range of specifications – from GCSE and A Level Biology in the UK to IGCSE and IB Biology internationally – she knows what is required to pass those Biology exams.