Externality DSE 答題技巧
做Econ past paper時遇到externality的題目經常無從入手？
寫了一大堆東西卻只有一分？
不知道不同題型的提問關鍵字？
那麼，這篇文章一定十分適合你。
今天學博小編為大家整理了3大DSE常見的externality題型，還會附上相應的答題flow及例題，希望能幫助到大家。
DSE externality 的長題目大概可以分成3類，每一類都有著密不可分的關係，而且必定能在 6個stpes 內寫完並全齊分數。
每類題型需要寫的steps如下：
Type 1: 1 – 2
Type 2: 1 – 4
Type 3: 1 – 6
只要分清每一類題型的提問關鍵字，即能在最短的時間內輕鬆全取分數。
Type 1: why involve externality
答題flow
Positive externality
-Explain how the affecting party benefits the affected party without receiving compensation from the affected party.
-There exists external benefit/is a divergence between private and social benefit/is a positive externality, with marginal social benefit greater than marginal private benefit.
Negative externality
-Explain how the affecting party affect (negatively) the affected party without paying compensation to the affected party.
-There exists external cost/is a divergence between private and social cost/is a negative externality, with marginal social cost greater than marginal private cost.
例題
2016/DSE/II/4
These years many customers like to take photos of the food they have in restaurants and share them on social media. However, some high-end restaurants do not allow their customers to take photos. Explain how the ‘’photo-taking-and-sharing’’ behaviour of the customers may involve externality. (3 marks)
Marking scheme
Taking photos may disturb other people in the restaurants/sharing he photos in the social media may disclose the design of dishes. Both possibilities may have an undesirable effect on the revenue/profit of the restaurants, but such effects are not compensated (financially or otherwise) by the photo-takers. Such photo-taking-and-sharing behaviour may thus involve positive externality (external benefit is involved). (3)
OR
Taking photos and sharing them in social media may have a promotion effect., attracting more customers-bringing hinger revenue/profit to the restaurant, but the photo takers do not receive compensation for such benefits. such photo-taking-and-sharing behaviour may thus involve negative externality (external cost is involved). (3)
Type 2: inefficiency
答題flow
Positive externality
-Explain how the affecting party benefits the affected party without receiving compensation from the affected party.
– There exists external benefit/is a divergence between private and social benefit/is a positive externality, with marginal social benefit greater than marginal private benefit.
-Marginal social benefit is greater than marginal social cost.
-The number of existing _____ is lower than the efficient level.
Negative externality
-Explain how the affecting party affect (negatively) the affected party without paying compensation to the affected party.
– There exists external cost/is a divergence between private and social cost/is a negative externality, with marginal social cost greater than marginal private cost.
– Marginal social cost is greater than marginal social benefit.
-The number of existing _____ would exceed the efficient level.
例題
2017/DSE/II/4
Pokémon Go is popular game for which gamers need to move around different places with their smartphone to catch the cyber-pets. Its developer has placed hotpots in different areas where many gamers are attracted to gather. Some restaurants in remote areas found their business sharply increase as they are located near these hotpots.
a) Based on the above information, explain, in terms of externality, how the placing of the hotspots may result in inefficiency. (3 marks)
b)How may such a problem of inefficiency be relieved by market? (2 marks)
Marking scheme
a) Positive externality. Restaurant in remote areas enjoy benefits from increased business due to the game developer’s choice of hotspots locations without paying the developer. So external benefit exists and marginal social benefit is greater than marginal social cost. The number of existing hotspots near the restaurants is lower than that required by the efficient level. (3)
b) The restaurants may pay the game developer to increase the hotspots nearby. (2)
OR
The game developer may charge the restaurants for placing more hotspots near them. (2)
Type 3: How efficiency improves?
答題flow
Positive externality
-Explain how the affecting party benefits the affected party without receiving compensation from the affected party.
– There exists external benefit/is a divergence between private and social benefit/is a positive externality, with marginal social benefit greater than marginal private benefit.
-Marginal social benefit is greater than marginal social cost.
-The number of existing _____ is lower than the efficient level.
-_____ (e.g., subsidisation) can increase the quantity of _____ towards the efficient level.
-This can narrow the gap between marginal social benefit and marginal social cost.
Negative externality
-Explain how the affecting party affect (negatively) the affected party without paying compensation to the affected party.
– There exists external cost/is a divergence between private and social cost/is a negative externality, with marginal social cost greater than marginal private cost.
– Marginal social cost is greater than marginal social benefit.
-The number of existing _____ would exceed the efficient level.
-_____ (e.g., taxation/charges/penalties) can reduce the quantity of _____ towards the efficient level.
-This can narrow the gap between marginal social benefit and marginal social cost.
例題
2019/DSE/II/4
Getting vaccinated is an effective way to prevent infection and protect oneself from flu viruses. Using the concept of externality, explain why the government provision of subsidy on Seasonal Influenza Vaccination (接種季節性流感疫苗) may improve economic efficiency. (4 marks)
Marking scheme
Getting vaccinated protects oneself as well as lowering the chances of others being infected by flu. Since the person receiving vaccination is not compensated by others (whose chances of being infected are reduced), there exists external benefit, with marginal social benefit exceeding marginal social cost. This implies that the number of people getting vaccinated is below the efficient level. Subsidy can increase the quantity of vaccination towards the efficient level and thus narrow the gap between marginal social benefit and marginal social cost. (4)
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DSE Econ 文章系列
Microeconomics
Macroeconomics
- 經濟表現的量度 Measure of economic performance
- 國民收入決定及價格水平 National income determination and price level
- 貨幣與銀行 Money and Banking
- 宏觀經濟問題和政策 Macroeconomic Problems and policies
- 國際貿易和金融 International Trade and Finance
