Externalities Definition (Examples, Positive, Negative) - BoyceWire
Externalities Definition

Externalities Definition

Externalities Definition
Examples, Positive, Negative

WRITTEN BY PAUL BOYCE | Updated 23 March 2021

Externalities Definition

The origins of ‘externality’, comes from the Latin word ‘externus’ – meaning ‘outside’ or ‘outward’. Essentially, it translates to the state of being outside – although its economics definition is more meaningful.

In economics, externalities are a cost or benefit that is imposed onto a third party that is not incorporated into the final cost. For example, a factory that pollutes the environment creates a cost to society, but those costs are not priced into the final good it produces.

These can come in the form of ‘positive externalities’ that create a benefit to a third party, or, ‘negative externalities’, that create a cost to a third party. What’s more, these externalities occur both during production and/or consumption.

Key Points
  1. An externality is a cost or benefit imposed onto a third party, which is not factored into the final price.
  2. There are four main types of externalities – positive consumption externalities, positive production externalities, negative consumption externalities, or negative production externalities.
  3. Externalities create a social cost where goods are undersupplied or create damage to the environment.

Production externalities occur when a manufacturer releases pollution into the atmosphere during its production process. There are also consumption externalities that occur during the consumption of a good. For example, smokers release toxic fumes into the atmosphere that can be detrimental to the health of those who inhale the fumes – thereby creating a negative externality through pollution.



Positive Externalities

Positive externalities occur when a third party benefits at no direct cost. For example, there are hundreds of shops in the mall, but the average consumer doesn’t go to see them all. Instead, they go to a few specific shops that they want to buy from. Yet other stores may benefit if the consumer goes into more stores than originally planned. Consequently, other stores can benefit from the popularity of its surrounding stores.

Another example of a positive externality is where new software increases the productivity of a business. For instance, if businesses are more productive and efficient, they have lower production costs, which, in turn, allow it to charge lower prices to consumers. So indirectly, the consumer benefits from such advances.

Positive Externality Example

We also have public goods, which tend to have positive externalities. For example, street lights provide drivers and pedestrians with enhanced visibility during the night. Both benefit without a direct cost being imposed on them. However, they don’t just benefit from greater visibility, but also a lower risk of an accident, which not only benefits drivers and pedestrians but also insurance companies.

As we can tell from this brief example, certain goods can benefit more than one third party. Not only do drivers benefit from fewer accidents, but insurance companies also benefit from fewer claims. However, the quantifiable benefit is impossible to calculate – we cannot simply work out how much each party gained.

It is impossible to predict how much this saves insurance firms, nor how many lives it saves. So whilst we consider such a positive externality, there are equal negative externalities to consider.

“Street lights provide drivers and pedestrians with enhanced visibility during the night. Both benefit without a direct cost being imposed on them.”

As with any government spending, it takes money away from private hands and directs this to areas where it sees fit. The external cost is that private firms and individuals have less disposable income. So although positive externalities are created, they are balanced out by potential negative externalities. This is because the private sector has fewer funds in order to be able to invest in productive equipment.


Examples of Positive Externalites

Positive externalities can be split down into two types: production, and consumption. Let us look at some examples of these below.

Examples of Positive Production Externalities
Examples of Positive Consumption Externalities

Positive Production Externalities

Positive production externalities occur when a third party benefits from the production of another. The issue arises when the third party cannot be charged for receiving such benefits. For example, a bakery may send the smell of fresh bread through the mall. Yet all those who benefit are not charged, and the baker has no way of charging them either.

Some examples include:

examples of Positive production externalities

1. Local Construction

The construction of new local businesses and other amenities may increase the value of local properties – thereby creating a positive benefit to local residents. They also create jobs that provide income to residents, which can then further stimulate economic activity in the locality. In turn, local residents benefit even if they do not use such a business.

2. New Technology / Process

The advancement of technology has inevitably’ created private benefits. Many firms benefit from productivity gains, which has created positive spillover effects.

For example, if business A is spending $10 million less on producing jumpers, it means those resources can be spent elsewhere. Rather than $10 million being spent on producing the same number of jumpers, it can be spent on producing a new style of pants or more staff. Those new pants may become incredibly popular, but wouldn’t be achieved without the initial productivity gains from technology.

3. Training

A business may train its employees with a specific skill, with the business and employee both sharing the benefits and productivity gains. However, when the employee leaves, the new employer will benefit from the original training and skills acquired.

Examples include training such as First Aid, or Mental Health training, whereby third parties can save lives or help individuals outside of the company. Therefore training can also benefit parties from outside of the firm as well.

4. Pharmaceuticals

Innovation in the pharmaceutical market is a debated and highly charged topic. For instance, it charges high prices due to research and development costs and risk factors. However, it can provide positive external benefits. If a new drug saves a life, it produces a private benefit to the company as well as the saved individual. At the same time, other parties also benefit. For example, family and friends no longer have to fear losing a close friend or loved one, and the grief it would bring.



Positive Consumption Externalities

Positive consumption externalities occur when a third party benefits from somebody else’s consumption. Let us take some examples:

Positive consumption externalities examples


1. Advertising

When McDonalds, Walmart, or some other big firm advertises, it solves a market failure. For example, it allows services such as Twitter, free-to-air television, and YouTube, remain free. So when you’re watching a YouTube video; you are benefiting from advertisers paying YouTube. Whilst adverts can be annoying, they allow us to view and use such services for free.

2. Education

The procurement of any form of education has the potential to benefit a third party. For example, learning how to read and write at school benefits society as a whole because we communicate more effectively. Without an education, we would not be able to read now, nor would we be able to communicate effectively. For every article or post you read, you are the third party that benefits from that individual’s education.

3. Insurance

Having insurance can create a positive externality. For example, when a third party has their vehicle totaled by a reckless driver, it can create a nightmare situation. There may be $30,000 worth of damages and without the culprit having insurance, they may have to shoulder the cost themselves.

The reckless driver may not have the money to pay for the damages so the third-party has a cost imposed upon them. However, insurance resolves this issue. Should a third party be injured or their car damaged, they can make a claim.

4. Local Investment

Neighbours may invest in their property – developing a new drive or making their house more pleasantly attractive. In turn, this can result in increased market values to third parties in the local area if it makes the area seem more desirable and picturesque.

5. Vaccinations / Personal Hygiene

When we receive vaccinations or take steps to prevent ourselves from contracting a contagious disease, we pass on a benefit to a third party. As a result, we decrease the likelihood of disease from spreading.



Negative Externalities

Negative externalities impose a cost onto a third party without prior knowledge or consent. These externalities occur during an economic transaction between two parties. There are then negative consequences that result, which the third party is not compensated for.

It is said that these negative externalities cause social costs. For example, CO2 contributes to global warming, damage to the environment, and the ozone layer. This is a social cost that is burdened upon all of society. Therefore, the use of CO2 emitting goods creates a negative externality that brings a cost to society. One solution that is frequently cited, is to enforce payment on such individuals or organizations and then redistribute this to the affected parties.

Examples of Negative Externalities

A negative externality is where a cost is imposed onto a third party involuntarily. In turn, governments generally look to step in to resolve such issues. After all, it is hardly fair to have to pay for something that is somebody else’s fault.

These externalities can be split down into production and consumption:

Examples of Negative Production Externalities
Examples of Negative Consumption Externalities

Negative Production Externalities



1. Air pollution

As manufacturers produce cars, televisions, and other goods – they leave Carbon emissions. An example of this was visible in 1952 during ‘The Great Smog of London’. Over the course of 5 days, it is estimated that 6,000 died from air pollution. Obviously this is a very extreme case but is an example of how there can be serious external effects from air pollution.

2. Noise pollution

You may live on a main road, or have noisy neighbours. Either way, a third party cost is imposed upon you through noise pollution. In some studies, this can be associated with increased blood pressure and heart conditions. Obviously a very serious externality.

3. Construction of New Houses

If more houses / apartments are being built in the local area; the value of the surrounding houses will likely take a hit. As there is more supply in the area, existing home-owners may find it less profitable to sell.



Negative Consumption Externalities

Negative Consumption Externalities Examples

1. Smoking and Air Pollution

Slightly different from industrial pollution; smoking is a form of consumption that impacts on a third party. The effects are widely known and can be associated with a higher risk of cancer not only for the individual smoking, but also those inhaling the fumes.

2. Rising Obesity

Higher obesity levels are associated with health conditions such as heart disease. This is a private cost but can impose an additional cost on third parties. As a result, the treatment required has to be paid for, which can come in the form of higher insurance costs; impacting other customers. Or, in government-run systems, it will be paid for by the taxpayer.

3. Litter

After consuming a beverage or food item, the leftover packaging may be thrown on the floor. This creates a cost to the average passer-by in the form an unpleasant sight, as well as the impact on the natural environment.

4. Traffic

In big cities, traffic is a nightmare. People will spend hours of their lives stuck in it. Yet the third-party that pays the cost is other users.


Private vs Social Costs

To understand externalities, it is important to understand the imposed costs. These come in the form of private, social, and external costs.

  • A Private Cost is essentially the price paid by a person or firm for a product/service.
  • A Social Cost is the sum of the Private Cost in addition to any external costs.
  • An External Cost refers to the externalities discussed above. So for example, the cost of air pollution may come to $50, so would be included as an ‘external cost’.

Social Cost = Private Cost + External Cost


Example of Social Cost

A social cost is the sum of a private cost in addition to an external cost (negative externality). The cost to use your car in the morning may by $5. That is the private cost.

There are external costs that include: air pollution, noise pollution, and traffic. Obviously, it is extremely difficult to value such externalities, which makes calculating the total social cost very complex and open to interpretation. Nevertheless, for this example, let us assume these costs amount to $2.50 – that is the external cost. So the overall social cost would be $5 in private costs plus $2.50 in external costs, leading to a total of $7.50.

Social Cost $5 in Petrol + $2.50 in cost of air and noise pollution


Importance of Social Cost

When the social cost exceeds private cost, we have what is commonly known as market failure. This is because all of the total cost is not paid by the customer. So for example, when a plane flies, it causes noise and air pollution. The customer pays for their flight, but there is an external cost imposed on a third party that is not paid for by the customer. This is essentially what carbon emission taxes seek to address.


Remedies to Externalities

1. Refined Property Rights

When there are refined property rights, all parties are able to negotiate the cost of the externality. For example, an owner of a fishery may be affected by downstream pollution from an industrial firm. The owner of the fishery is able to sue the industrial firm in order to be compensated for the effect it has had on them. In turn, a settlement can be reached to be reimbursed for that negative externality.

2. Taxes

When there are externalities such as pollution, one remedy is to tax them based on units of consumption. For example, a firm that produces 10 thousand tonnes of C02 will be taxed at a rate of $1,000 per tonne. These taxes could then be used to pay for positive externalities such as education and other public goods.

3. Subsidies

Positive externalities are underproduced when the whole social benefit is greater than the private benefit. In such situations, the good is underproduced because private individuals value the good at a lower rate than the overall value it provides to society. One way to resolve this is by offering subsidies and other financial incentives. For instance, many governments offer a ‘green scheme’ to make it more affordable to purchase electric cars.

4. Regulation

Another remedy to address externalities is regulation. By making negative externalities illegal, they may address some of the side effects that occur and reduce its consumption and production. For instance, many countries have now made it illegal to smoke in a public place, which has helped reduce the effects of second-hand smoke.




General FAQs on Externalities

What is an example of an externality?

When McDonalds, Walmart, or some other big firm advertises, it solves a market failure. It allows services such as Twitter, free-to-air television, and YouTube to remain free. So when you’re watching a YouTube video; you are benefiting from advertisers paying YouTube. Whilst adverts can be annoying, they allow us to view and use such services for free.

What are the 4 types of externalities?

The 4 types of externalities can be split between positive and negative. There are positive production and positive consumption externalities, and there are also negative production and negative consumption externalities.

What are externalities in economics?

An externality refers to a cost or benefit that is imposed onto a third party. These can come in the form of ‘positive externalities’ or, ‘negative externalities’.




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