2023 Cambridge IAL Economics (9708) 模擬試題連答案詳解

1. Market Classification: A 75% market share indicates an extremely high concentration ratio. While a pure monopoly is a single seller (100% market share), in practice, a firm with 75% market share acts as a dominant firm monopoly or operates within a highly concentrated oligopolistic structure. Both classifications are acceptable if justified by the high concentration of market power.

2. Impact on Supernormal Profits: Commission fees represent the price of the platform's service. Increasing this fee from 15% to 25% increases Platform A's average revenue (AR) and marginal revenue (MR). Since Platform A has a dominant 75% market share, delivery riders and consumers have few viable alternatives, making demand for its platform services relatively price inelastic. Consequently, total revenue will rise significantly. Provided that any increase in operational costs does not exceed the increase in revenue, Platform A's supernormal profits will expand in the short run.

Up to 2 marks for market classification and justification:
- 1 mark for identifying the structure as an oligopoly, a dominant-firm oligopoly, or a monopoly.
- 1 mark for explaining this choice by referencing the high market concentration (75% market share).

Up to 3 marks for analysis of supernormal profits:
- 1 mark for explaining that raising the fee increases average and marginal revenue per transaction.
- 1 mark for explaining that demand is likely to be price inelastic because of Platform A's dominant market position and lack of close substitutes.
- 1 mark for concluding that supernormal profits will increase if total revenue rises more than total costs.

1. Binding Minimum Wage: The statutory minimum wage of $11.00 is set above the market equilibrium rate of $8.50, which means it is a binding minimum wage that prevents the market from clearing naturally.

2. Quantity Demanded vs. Quantity Supplied: At the higher wage of $11.00, the marginal cost of hiring increases for platform companies, leading to a contraction in the quantity of labour demanded. Conversely, the higher wage attracts more workers to the delivery sector, leading to an expansion in the quantity of labour supplied.

3. Market Outcome: This mismatch between the higher quantity of labour supplied and the lower quantity of labour demanded results in a market disequilibrium, specifically an excess supply of labour (unemployment/surplus of delivery riders). In the platform economy, this surplus may manifest as platforms restricting rider access, increasing shift competition, or raising fees on consumers.

- 1 mark for identifying that the statutory minimum wage of $11.00 is binding because it is set above the current market equilibrium wage of $8.50.
- 1 mark for explaining the contraction in the quantity of labour demanded by platforms due to higher wage costs.
- 1 mark for explaining the expansion in the quantity of labour supplied as more riders are attracted to the higher wage.
- 1 mark for identifying the resulting excess supply of labour (unemployment/surplus of workers).
- 1 mark for applying the analysis to the gig-economy context (e.g., platforms limiting active rider logins, increasing consumer delivery fees, or reducing bonuses).

1. Private Costs: These are the internal costs incurred directly by the consumers or producers involved in the transaction. In this case, private costs include the cost of fuel, moped depreciation and maintenance, and platform commission fees paid by the riders and platforms.

2. External Costs: These are negative spillover effects imposed on third parties who are not involved in the transaction. According to the data, these include the 40% increase in localized carbon emissions (air pollution affecting residents' health) and the 18 hours of additional congestion delays suffered by other road users.

3. Market Failure: Because economic agents (riders and consumers) only consider their private costs and private benefits, the market equilibrium is established where Marginal Private Cost (MPC) equals Marginal Private Benefit (MPB). Since external costs are ignored, the Marginal Social Cost (MSC) is greater than the Marginal Private Cost (MPC). This leads to the overproduction and overconsumption of delivery services, where MSC exceeds Marginal Social Benefit (MSB), resulting in allocative inefficiency and a deadweight welfare loss to society.

- 1 mark for defining private costs with an appropriate example from the case study (e.g., fuel, moped maintenance).
- 1 mark for defining external costs with reference to the case study's data (e.g., 40% emission increase or 18 hours of congestion delays).
- 1 mark for defining social cost as the sum of private and external costs (or stating that MSC > MPC).
- 2 marks for explaining why market failure occurs (overproduction/overconsumption due to ignoring negative externalities, leading to MSC > MSB at the market equilibrium, causing a deadweight welfare loss).

1. Frictional vs. Structural Unemployment:
- Frictional unemployment is short-term, temporary unemployment that occurs when workers are in the process of searching for or transitioning between jobs.
- Structural unemployment is long-term unemployment arising from structural changes in the economy (such as the closure of traditional retail stores due to online delivery platforms) that leave workers with skills that do not match the requirements of the available jobs.

2. Gig Economy's Impact:
- Reducing Unemployment: The gig economy has low barriers to entry and rapid onboarding, which helps absorb frictionally unemployed workers quickly, explaining the drop in the official unemployment rate from 6.2% to 4.5%.
- Failure to Solve Structural Issues: However, the gig economy does not solve structural unemployment. Working as a delivery rider or driver does not provide displaced retail workers with the high-level digital or technical skills required in the modern economy. Additionally, it may simply mask underemployment, as these workers are often underemployed in precarious, low-paying roles rather than being securely employed long-term.

- 2 marks for distinguishing between frictional unemployment (short-term, transitional) and structural unemployment (long-term, skill/geographical mismatch due to economic shifts).
- 1 mark for explaining how the gig economy reduces frictional unemployment (low barriers to entry, flexible/immediate absorption of job seekers).
- 2 marks for analyzing why the gig economy does not solve long-term structural issues (does not retrain structurally displaced retail workers, leads to precarious employment/underemployment, and does not build high-value skills).

Introduction: Market failure in the public transport sector arises primarily due to positive externalities of consumption. When individuals use public transport instead of private cars, they reduce road congestion, lower greenhouse gas emissions, and decrease traffic accidents. Because consumers only consider their private benefits (marginal private benefit, \(MPB\)) rather than the wider social benefits (marginal social benefit, \(MSB\)), the market equilibrium where \(MPB\) equals marginal private cost (\(MPC\)) leads to under-consumption and under-provision. The social optimum is achieved where \(MSB\) equals marginal social cost (\(MSC\)). Since \(MSB > MPB\), a deadweight loss is created in a free market, representing allocative inefficiency. Subsidies to Private Operators: A government subsidy paid to private transport operators lowers their production costs, shifting the supply (\(MPC\)) curve downward and to the right. This increases the quantity of public transport services supplied and lowers the market price (fare). If the subsidy is equal to the marginal external benefit (\(MEB\)) at the social optimum, the price falls to the socially optimal level, and consumption increases to the allocative efficient level where \(MSB = MSC\), thus internalizing the positive externality. Maximum Fares: A maximum price (price ceiling) set below the free-market equilibrium fare ensures that public transport remains affordable, particularly for low-income households. This addresses the macroeconomic objective of equity and prevents private monopolies (which often exist in local transit markets) from exploiting consumers through excessively high fares. Evaluation of the Policy Combination: The combination of these two policies can be highly complementary. Ordinarily, a maximum price set below the market-clearing equilibrium creates a shortage (excess demand over supply), leading to queues, black markets, or deterioration in service quality. However, when combined with a subsidy, the downward shift in the supply curve can increase quantity supplied sufficiently to meet the higher demand at the maximum fare, preventing a shortage. However, several limitations exist. First, calculating the precise monetary value of external benefits to determine the correct subsidy is extremely difficult, risking over- or under-subsidization. Second, subsidies carry a significant opportunity cost for government budgets and can breed X-inefficiency, as private firms lose the incentive to minimize operating costs when they rely on state support. Third, if the maximum price is set too low relative to the subsidy, private operators may still lack the financial incentive to maintain vehicle safety or expand routes to less profitable areas, worsening service quality. Alternative and Complementary Policies: Direct state provision (nationalization) could avoid the need to balance subsidies with maximum fares, allowing the government to run the transport network directly at the socially optimal price and output, though this risks public-sector inefficiency. Alternatively, governments could target the substitute market by imposing congestion charges or higher fuel taxes on private car owners. This internalizes the negative externalities of driving, shifting the demand curve for public transport to the right, which reduces the level of subsidy needed to achieve the socially optimal level of public transport consumption. Conclusion: In conclusion, a combination of subsidies and maximum fares is a powerful way to achieve efficient resource allocation, as the subsidy can counteract the shortages typically caused by price ceilings. However, its effectiveness is constrained by fiscal limits and information failures. A more comprehensive approach would combine these supply-side policies with demand-side penalties on private vehicle use to achieve long-term allocative efficiency.

AO1 and AO2 (Knowledge, Understanding and Analysis) - Max 12 marks. 9 to 12 marks: Clear and detailed analysis of market failure in the public transport sector (positive externalities of consumption, MSB greater than MPB, and allocative inefficiency). Detailed explanation of how a subsidy shifts supply to lower fares and increase output, and how maximum prices ensure affordability and limit monopoly power. High-quality structure with precise economic terminology. 5 to 8 marks: Good understanding of the policies and market failure, but the links between the policies (e.g., how they interact or how they correct the externality) are less developed. Some use of economic concepts but may lack depth. 1 to 4 marks: Superficial answer showing basic knowledge of subsidies or price controls, but with significant omissions or errors. AO3 (Evaluation) - Max 8 marks. 7 to 8 marks: Critical, multi-layered evaluation of the limitations of both policies (opportunity cost, X-inefficiency, risk of shortages). Evaluates the combination of the policies rather than just analyzing them individually. Compares with alternatives like state provision or road pricing. Offers a clear, reasoned conclusion. 4 to 6 marks: Some evaluation of the limitations of the policies, but might focus on them in isolation. Alternative policies are mentioned but not fully integrated into a cohesive judgment. 1 to 3 marks: Unsubstantiated or very brief evaluative comments.

Introduction: Define sustainable economic growth as growth that meets the needs of the present without compromising future generations, balancing economic expansion with environmental preservation. Define full employment and price stability. The thesis is that while these policies can cause short-run structural unemployment and cost-push inflation, these conflicts are not inevitable in the long run if supported by appropriate complementary policies. Section 1 - Analysis of Conflicts: First, conflict with price stability (green inflation / cost-push inflation) occurs because strict environmental regulations and carbon pricing raise marginal costs of production. This can be illustrated with an AD/AS diagram where a leftward shift of the SRAS curve from \(SRAS_1\) to \(SRAS_2\) leads to a higher price level and lower real output. Second, conflict with full employment (structural unemployment) arises as decarbonisation requires winding down carbon-intensive industries, causing workers with non-transferable skills to face structural unemployment. Section 2 - Analysis of Compatibilities: First, compatibility with full employment (green job creation) occurs because government subsidies and public investment in green technology act as an injection, shifting AD to the right and creating new jobs. Second, compatibility with price stability occurs because transitioning to domestic renewable energy reduces vulnerability to international oil and gas price shocks. Over time, green technology advancements shift the LRAS curve to the right, supporting non-inflationary growth. Section 3 - Evaluative Discussion: The conflict is not inevitable. In the short run, transitional friction leads to structural unemployment and inflation. However, in the long run, economies adapt and achieve economies of scale in green tech. The choice of policy matters: investment-based policies are less inflationary than heavy taxation. Furthermore, active labour market policies (like retraining schemes) can mitigate structural unemployment, meaning conflicts can be managed and are not inevitable.

AO1 and AO2 (Analysis): 12 Marks. Level 3 (9-12 marks): Coherent, detailed, and well-structured economic analysis of how green growth policies impact employment and inflation. Explains both conflict channels and cooperative channels. An accurate AD/AS diagram is fully integrated and explained. Level 2 (5-8 marks): Good analysis of the impacts but lacks depth, or focuses on only one objective, or has minor errors in explanations or diagrams. Level 1 (1-4 marks): Superficial or largely descriptive response. AO3 (Evaluation): 8 Marks. Level 3 (6-8 marks): Critical evaluation of the word 'inevitably'. Explicitly discusses the distinction between the short run and the long run, the influence of different policy designs, and the critical role of complementary policy measures (e.g., retraining schemes), leading to a well-reasoned conclusion. Level 2 (3-5 marks): Some evaluative discussion but lacks depth or a well-supported final conclusion. Level 1 (1-2 marks): Minimally evaluative.