EKN 320: Economic Analysis 320 Exam Notes

Economic Analysis 320 (EKN 320) is designed to help you interpret how economic agents—households, firms, and governments—make decisions under scarcity. The exam usually tests whether you can translate economic reasoning into formal tools: graphs, elasticity and incidence, cost–benefit logic, market structure comparisons, and policy evaluation using welfare concepts. These notes are built to help you answer typical exam-style questions clearly, consistently, and with the underlying economic logic expected by South African university and TVET marking standards.

Section 1: Core Economic Reasoning for EKN 320 (Models, Welfare, and Graph Technique)

Economic analysis begins with disciplined problem framing. Many students lose marks not because the final answer is wrong, but because they cannot justify it using the correct economic mechanism (opportunity cost, marginal thinking, equilibrium, incentives, and welfare). EKN 320 often assumes you can move between verbal reasoning and mathematical or graphical representations.

Economic Questions You Must Be Able to “Translate” Into Tools

A useful exam habit is to identify the “type” of question before you start calculating:

1. Positive analysis (what happens?)

   • Example prompts: “What is the effect of a tax on quantity and price?”
   • You must predict direction of change and relative magnitude.

2. Normative analysis (what should happen?)

   • Example prompts: “Is this policy welfare-improving?”
   • You must discuss producer surplus, consumer surplus, deadweight loss, and distributional effects.

3. Efficiency and equity trade-offs

   • Example prompts: “Who benefits and who bears costs?”
   • You must describe incidence (who actually pays/receives) rather than assuming statutory responsibility.

4. Time dimension

   • Example prompts: “In the short run vs long run, how do firms adjust?”
   • You must reflect that fixed factors constrain adjustment in the short run.

If you can correctly classify the question type early, your graph choices and interpretations become more reliable.

Welfare Framework: Surplus, Deadweight Loss, and Efficiency

Most EKN 320 exam questions use some welfare language even when the question seems “technical.” Your goal is to compute or qualitatively determine how policies affect:

• Consumer Surplus (CS): difference between what consumers are willing to pay and what they actually pay.
• Producer Surplus (PS): difference between what producers receive and their willingness to supply (typically linked to marginal cost).
• Total Surplus (TS): CS + PS.
• Deadweight Loss (DWL): efficiency loss from market distortions (e.g., taxes, price controls) that reduce mutually beneficial trades.

Standard Graph Setup

A typical demand–supply diagram includes:

• Demand downward sloping: marginal willingness to pay falls as quantity rises.
• Supply upward sloping: marginal cost rises as output increases.
• Equilibrium at intersection: quantities that maximize total surplus in a frictionless market.

What examiners look for

When a distortion occurs:

• Quantity falls below the efficient level.
• Transfer payments (e.g., from consumers to government via a tax) are not always “losses.”
• Efficiency loss shows up as triangles between curves (where trades that would have occurred do not happen).

A tax typically creates:

• A wedge between consumer price and producer price.
• A smaller equilibrium quantity than the no-tax equilibrium.
• A redistribution: CS decreases and PS decreases; part of the loss becomes government revenue; remaining part becomes DWL.

Elasticity: The Key to Incidence and Policy Impact

Elasticity is central to almost every “who bears the burden?” question. EKN 320 expects you to use the elasticity logic correctly.

Price Elasticity of Demand and Supply

• Demand elasticity determines how sensitive consumers are to price changes.
• Supply elasticity determines how quickly producers can adjust output or pricing.

Rules of thumb for tax incidence:

• More inelastic side bears a greater share of the tax.
• Formally, if demand is more inelastic than supply, consumers pay more of the tax (greater portion of the wedge appears as a higher price paid by consumers relative to the producer price received).
• If supply is more inelastic than demand, producers bear more.

Graph-based elasticity intuition

• Steeper demand (more inelastic): quantity responds less to price.
• Steeper supply (more inelastic): producers cannot adjust quickly.

To score well, you must connect elasticity to incidence, not just repeat “more inelastic pays.”

Opportunity Cost and Marginal Thinking

EKN 320 also tests whether you can apply opportunity cost and marginal reasoning beyond textbook tax examples.

Opportunity cost

Whenever the question involves “choice,” “allocation,” “investment,” or “resource use,” the correct answer must recognize opportunity cost:

• The cost of using a resource is the value of the next-best alternative.
• This becomes vital in cost–benefit analysis (CBA), project evaluation, and welfare comparisons.

Marginal thinking

Many policy questions ask you to assess whether marginal benefits exceed marginal costs:

• If MB > MC, expand the activity.
• If MB < MC, reduce the activity.
• If MB = MC, the decision is efficient (for competitive markets under standard assumptions).

Even for graphical questions, you can often identify which curves represent MB and MC.

From Models to Answers: A Practical Exam Answer Template

A strong exam response usually follows a reliable sequence:

1. Identify the market and the distortion/policy (tax, quota, subsidy, price control, regulation).
2. Describe equilibrium adjustment (which price/quantity changes and in which direction).
3. Use incidence logic (based on elasticities).
4. Evaluate welfare:
   • Compute or state changes in CS and PS.
   • Identify government revenue.
   • Determine DWL.

Mini-example (structure only)

For a specific tax:

• Quantity falls from (Q_0) to (Q_1).
• Consumer price rises from (P_0) to (P_c).
• Producer price falls from (P_0) to (P_p).
• CS ↓, PS ↓.
• Government revenue = wedge × tax quantity.
• DWL = triangular loss due to fewer transactions.

You don’t always need numbers; you need correct logic and the correct elements.

South African Context You Should Know (Without Overfitting)

South African exam questions sometimes use local settings—fuel prices, electricity tariffs, VAT implications, or agricultural marketing. Even when the data is generic, the institutional context helps you interpret constraints.

Common links:

• Regulation and price controls can appear in energy, transport, and essential goods contexts.
• Tax policy often relates to VAT or excise-like instruments.
• Market structure matters in industries like telecoms, retail, and food supply chains.

Your key is not to memorize local facts but to understand how the same economic tools apply to South African institutions and market features (e.g., imperfect competition, information gaps, and infrastructure constraints).

Section 2: Microeconomic Tools—Taxes, Subsidies, Market Power, and Welfare Effects

This section focuses on the microeconomic mechanics that show up frequently in EKN 320 exams: taxes and subsidies, market power and deadweight loss, and the comparative statics that follow from demand/supply shifts and elasticities.

Taxes: Analysis, Incidence, and Welfare

Step-by-step structure for a typical “tax” question

Assume a per-unit tax (t) on consumers or producers (the incidence depends on elasticities).

1. State the no-tax equilibrium

   • Price (P_0), quantity (Q_0).

2. Describe the wedge introduced by the tax

   • Consumer price becomes (P_c).
   • Producer price becomes (P_p).
   • Wedge size: (P_c – P_p = t).

3. Determine the new equilibrium

   • Quantity falls to (Q_1).

4. Incidence

   • Who pays more depends on elasticities:
     • More inelastic side bears more.
   • In diagrams:
     • Compare how much of the wedge shows up as a rise in consumer price vs a fall in producer price.

5. Welfare

   • CS decreases (transfer and loss).
   • PS decreases (transfer and loss).
   • Government revenue equals (t \times Q_1).
   • DWL arises because the total surplus from trades between (Q_1) and (Q_0) disappears.

Common errors

• Confusing government revenue with welfare loss. Revenue is a transfer.
• Claiming the statutory payer bears the full burden. In reality, incidence depends on elasticities.
• Ignoring the case where demand and supply elasticities change over time.

Subsidies: When Government Expands Output (and When It Doesn’t)

Subsidies can be per-unit, tax credits, or cost support. A subsidy reduces the effective price paid by consumers or the cost faced by producers.

Exam logic for a subsidy

• Subsidy increases output from (Q_0) to (Q_1).
• Consumer price decreases to (P_c) (if subsidy to producers, consumers may pay less relative to baseline).
• Producer price increases to (P_p) (depending on which side receives the subsidy).
• CS and PS typically both rise (one side gets price advantage; total surplus may rise or fall depending on externalities and market failures).
• Government pays out subsidy: wedge × quantity.

Welfare nuance: subsidy may worsen efficiency

If the market is efficient (no externalities), subsidies generally create:

• Overproduction relative to the efficient quantity.
• DWL because trades that are not socially beneficial occur.

However, if there are positive externalities (e.g., education, research), subsidies can be welfare-improving by aligning private and social returns.

Deadweight Loss: From Distortion to Diagram Triangles

To interpret DWL questions:

• Identify the efficient output level (often where supply equals demand in a competitive market).
• Find the distorted output level (e.g., post-tax equilibrium).
• DWL is the difference between potential surplus and actual surplus created by constrained trades.

A strong response indicates:

• Why trades stop happening (wedge).
• Which range of quantities becomes non-mutually beneficial.

In elasticity-heavy questions, DWL shape differs:

• If one side is very inelastic, quantity falls less, so DWL can be smaller.
• If both sides are elastic, quantity falls more and DWL can be larger.

Price Ceilings and Floors: Quotas, Shortages, Surpluses

EKN 320 frequently tests price control logic because it cleanly shows how markets ration without market-clearing prices.

Price ceiling (binding)

• If the ceiling is below equilibrium price, quantity demanded exceeds quantity supplied.
• Result: shortage and non-price rationing (queues, reduced quality, black market).
• Welfare:
  • CS can rise on paper due to lower price, but actual loss includes reduced quantity sold and distortions.
  • PS falls due to lower prices.

Price floor (binding)

• If the floor is above equilibrium, quantity supplied exceeds quantity demanded.
• Result: surplus and possible stockpiling.
• Government sometimes buys excess supply, which affects welfare through fiscal costs.

Quota logic

Quotas restrict the quantity allowed to trade, often producing:

• Higher prices for consumers.
• Lower prices for producers depending on quota design.
• Rent-seeking and inefficiency if rents are captured by license holders.

Market Power: Monopoly, Marginal Revenue, and Inefficiency

EKN 320 typically includes market structure analysis in some form. For monopoly:

Key monopoly conditions

• Monopoly chooses quantity where MR = MC.
• Price is read off the demand curve at that quantity (i.e., price > MC in general).
• Compared to competitive equilibrium (where P = MC), monopoly:
  • Produces less.
  • Charges a higher price.
  • Creates DWL.

Distinguishing monopoly logic from competition

Competitive equilibrium:

• Price equals marginal cost.
• Firms are price takers (MR = P).

Monopoly:

• MR declines faster than demand.
• MR lies below the demand curve.
• The wedge between price and marginal cost reflects markups.

Welfare effects

• CS decreases.
• PS can increase relative to the competitive benchmark (depending on how you define the baseline).
• Government revenue is often absent unless regulated.
• DWL increases due to reduced quantity.

Oligopoly and Strategic Interaction (Conceptual but Exam-Useful)

Even if the exam doesn’t require full game theory proofs, you should know:

• Oligopoly features interdependence: actions of one firm affect others.
• Price wars and collusion are possible.
• If a question asks “why markets may fail to coordinate,” you can relate to incentive constraints.

A commonly tested conceptual framework:

• Cartels can produce outcomes closer to monopoly (lower output, higher prices).
• Cartels are difficult to sustain because each firm has an incentive to deviate by undercutting.

Externalities and Market Failure: Why Policy Can Improve Welfare

When markets generate externalities, the private market outcome is not socially optimal.

• Negative externality (e.g., pollution): marginal social cost (MSC) exceeds marginal private cost (MPC).

  • Efficient output is lower than market output.
  • Taxes that align private costs with social costs can improve efficiency.

• Positive externality (e.g., vaccines): marginal social benefit (MSB) exceeds marginal private benefit (MPB).

  • Efficient output is higher.
  • Subsidies or provision can improve welfare.

Your exam responses should explicitly state:

• Which curve is “social” and which is “private.”
• Whether output should increase or decrease.
• How a policy corrects the wedge.

Case-Style Application: Policy Impacts and Welfare Accounting

Even without specific South African datasets, you can structure answers using “realistic policy contexts”:

Example scenario type (general)

Suppose a government imposes an excise tax on fuel. Economic analysis requires:

• Demand for fuel may be price inelastic short run.
• Supply capacity is limited and depends on refining/import logistics, which can be relatively inelastic too short run.
• Incidence depends on relative elasticities.
• Welfare:
  • Consumers face higher prices → reduced consumption.
  • Producers bear less/more depending on elasticity.
  • Government gains revenue.
  • DWL from reduced consumption relative to the efficient baseline.

If demand is relatively inelastic, the tax reduces quantity less, lowering DWL, though fiscal revenue could be high.

Skills Checklist for Micro Questions

Before you write final exam answers, confirm you included:

• Directionality (up/down for price and quantity).
• Incidence logic with elasticity.
• Welfare partition (CS, PS, revenue, DWL).
• Diagram correctness (curves labeled; wedge and triangles shown).
• Clear conclusion (e.g., welfare-improving vs welfare-reducing, depending on externalities).

Section 3: Quantitative Methods in Economic Analysis—Cost, Benefit, Discounting, and Choice Under Uncertainty

Many EKN 320 exams mix theory with quantitative evaluation. Even when the course name is “Economic Analysis,” the analysis often requires arithmetic, careful interpretation of formulas, and the ability to compare alternatives using consistent assumptions.

Cost–Benefit Analysis (CBA): The Core Logic

CBA compares at least two alternatives by evaluating:

• Benefits over time.
• Costs over time.
• The net benefits: benefits minus costs, typically in present value terms.

Why discounting matters

Money has time value: a rand today is worth more than a rand in the future due to interest rates and opportunity cost of capital.

Discounting converts future amounts to present equivalents so you can compare projects fairly.

Present Value (PV) and Discount Rate

Basic PV formula

For a cash flow (C_t) at time (t) discounted at rate (r):
[
PV = \frac{C_t}{(1+r)^t}
]

For multiple years, sum the PV across all periods:
[
PV_{\text{total}} = \sum_{t=0}^{T} \frac{C_t}{(1+r)^t}
]

Typical exam tasks

• Compute PV of costs and benefits given yearly cash flows.
• Compute Net Present Value (NPV):
  [
  NPV = PV(Benefits) – PV(Costs)
  ]
• Decide accept/reject:
  • If NPV > 0, accept (under standard criteria).
  • If NPV < 0, reject.

Worked Numerical Example (NPV)

Assume a project has:

• Initial cost at (t=0): R 1,000,000
• Benefits:
  • (t=1): R 400,000
  • (t=2): R 500,000
• Annual operating cost:
  • (t=1): R 100,000
  • (t=2): R 120,000
• Discount rate: 10% per year.

Compute PV of benefits:

• (PV_B = \frac{400,000}{1.1^1} + \frac{500,000}{1.1^2})
• (= 363,636.36 + 413,223.14 = 776,859.50) (approx.)

Compute PV of costs:

• (PV_C = 1,000,000 + \frac{100,000}{1.1^1} + \frac{120,000}{1.1^2})
• (= 1,000,000 + 90,909.09 + 99,173.55 = 1,190,082.64)

NPV:

• (NPV = 776,859.50 – 1,190,082.64 = -413,223.14)

Decision: Reject because NPV is negative.

This example mirrors what exams test: correct discounting, correct sign conventions, and correct summation.

Internal Rate of Return (IRR) and Payback (Conceptual + Calculation)

Some exams also ask about:

• IRR: discount rate that sets NPV to zero.
• Payback period: time until cumulative net benefits become positive (ignores discounting unless asked).

IRR can be tricky:

• You typically solve:
  [
  0 = \sum_{t=0}^{T} \frac{CF_t}{(1+r)^t}
  ]
• If multiple sign changes occur, IRR may not be unique.

If IRR questions appear, the safest approach is:

• State the method clearly.
• If computation is heavy, show setup and approximate results using trial discount rates.

Payback is simpler:

• Accumulate net cash flows year by year.
• Identify when cumulative becomes positive.

Examiners often like:

• A statement of strengths/weaknesses:
  • Payback ignores time value unless specified.
  • IRR can mislead if cash flows are not conventional.

Real vs Nominal Rates and Inflation (Common Exam Trap)

If a question provides:

• an inflation rate and an interest rate,
  you may need to adjust.

Approximate relationship:

• Real rate (r) approximates:
  [
  1+r_{\text{real}} \approx \frac{1+r_{\text{nominal}}}{1+\pi}
  ]
  where (\pi) is inflation.

If exams include inflation:

• Ensure cash flows are consistent: nominal cash flows discounted by nominal rate; real cash flows discounted by real rate.

A very common scoring mistake is mixing:

• nominal cash flows with real discount rates, or vice versa.

Opportunity Cost of Capital: Why the Discount Rate Isn’t Random

In CBA, the discount rate should reflect opportunity cost:

• In public sector projects, the social discount rate is often used.
• The rationale: funds could be used for alternative social investments.

In exam answers:

• If the discount rate is given, you just apply it.
• If asked “how should it be chosen,” say:
  • based on social opportunity cost of capital and risk considerations.

Risk and Uncertainty: Sensitivity, Scenario, and Expected Value

EKN 320 may include uncertainty evaluation. Key tools:

Expected Value (EV)

If cash flow outcomes have probabilities:
[
EV = \sum p_i \times CF_i
]

Sensitivity analysis

Change one key parameter (e.g., demand growth, cost escalation) and observe NPV changes.

Scenario analysis

Evaluate best case/base case/worst case with coherent assumptions.

Risk adjustments

Two approaches:

• Adjust discount rate upward for higher risk (higher r reduces PV).
• Or adjust cash flows downward/upward based on risk.

Exams typically reward clarity:

• Define the uncertainty variable.
• Show how the change affects NPV direction.

Cost Curves and Decision Rules (Micro Quant Meets CBA)

Economic analysis isn’t only CBA:

• You may use cost structures to evaluate shutdown, production decisions, or optimal scale.

Key concepts:

• Fixed costs do not change with output in the short run.
• Variable costs do change.
• Average cost and marginal cost often determine shut down/operate decisions:
  • In perfect competition, the firm supplies where (P = MC) (if producing).
  • Shutdown occurs when price falls below minimum average variable cost.

Even if the question doesn’t ask explicitly, it’s useful to recall these rules.

Opportunity Cost in Project Selection: Dominance and Incremental Analysis

When choosing between multiple projects:

• Use incremental NPV (difference between projects).

If project A dominates B (meaning it yields higher net benefits at lower or equal cost), B should be rejected.

A standard method:

1. Identify smallest viable scale.
2. Compare incremental benefits and costs.
3. Apply NPV.

This approach is often used in exam questions with multiple alternatives.

Section 4: Macroeconomic Interfaces—Fiscal/Monetary Policy Effects, Business Cycles, and Stabilisation Logic

While EKN 320’s core can be micro-leaning, many exams require macro interfaces: how government policy changes aggregate demand, how supply constraints affect inflation and employment, and how to evaluate stabilisation strategies using welfare and efficiency language.

Aggregate Demand–Supply (AD–AS): Interpreting Shocks

Even in an “economic analysis” course, AD–AS graphs can be used to interpret policy. The key is to identify:

• Which curve shifts (AD, short-run AS, long-run AS).
• What changes in price level and output follow.

Typical shock types

• Demand shock: shifts AD.
• Cost-push shock: shifts short-run AS.
• Supply-side improvement: shifts long-run AS (productivity growth).

A solid exam answer:

• States the direction of output change.
• States the direction of price change.
• If asked about the long run, explains that output tends toward potential given flexible prices and wage adjustments.

Fiscal Policy: Multipliers, Crowding Out, and Distribution

Fiscal policy includes:

• government spending changes,
• taxation changes,
• transfers.

Fiscal multiplier logic

In Keynesian frameworks, higher government spending can increase output through:

• direct spending,
• induced consumption,
• multiplier effects.

But in exam logic, you should also mention:

• leakages (imports, savings, taxes),
• crowding out (in the long run via interest rate/production constraints),
• capacity constraints (if the economy is near full employment, fiscal expansion may increase inflation more than output).

Budget constraint and sustainability

Even if the exam is not focused on public finance, you should acknowledge:

• If government spending increases without revenue, deficit increases.
• Long-run sustainability concerns can affect risk premia and interest rates.

Monetary Policy: Interest Rates, Inflation, and Transmission

Monetary policy typically affects output and inflation via:

• interest rate channel,
• exchange rate channel,
• asset price and expectation channels.

Key exam reasoning:

• If inflation is above target:
  • tight monetary policy raises interest rates,
  • reduces consumption and investment,
  • reduces aggregate demand and inflation pressures.

In more advanced reasoning:

• Policy affects expectations, which can influence wage and price setting.

Policy Trade-offs: Inflation vs Unemployment

A classic trade-off is:

• expansionary policy may reduce unemployment but can increase inflation,
• contractionary policy reduces inflation but can increase unemployment.

EKN 320 might ask you to evaluate which policy choice is better under conditions:

• high unemployment,
• high inflation,
• supply constraints,
• external shocks.

Marking tends to reward:

• stating the economic mechanism,
• connecting to appropriate diagram elements,
• acknowledging time horizons (short run vs long run).

Stabilisation Policy and Time Lags

Stabilisation policies often face:

• recognition lag (time to identify the shock),
• decision lag (time to implement),
• impact lag (time for the policy to affect real economy).

In exam answers:

• Mention lags if asked about effectiveness.
• Explain that lags mean policy might overshoot or arrive after conditions have already shifted.

A Structured Example: Interpreting a Negative Demand Shock

Suppose:

• consumer confidence drops,
• investment slows,
• exports fall due to global downturn,
• aggregate demand shifts left.

Policy options:

• fiscal stimulus to increase AD,
• monetary easing to lower interest rates and raise spending,
• structural policies (longer-term) to improve productivity and potential output.

An exam response should distinguish:

• short-run stabilization (increasing output),
• long-run adjustment (capacity and inflation stabilization).

Welfare Perspective in Macro

Even in macro, welfare logic can appear:

• output gaps imply inefficiency (resources underutilised),
• inflation has welfare costs (distortions and redistributive effects),
• fiscal and monetary policy should weigh trade-offs.

Some exam questions may frame:

• “Is austerity welfare-improving?”
  To answer:
• discuss distributional effects,
• the employment impacts,
• the long-run debt sustainability.

South Africa-Relevant Macro Interpretation (General, Tool-Based)

South African macro discussions often include:

• inflation sensitivity (fuel/food),
• unemployment and labour market frictions,
• exchange rate pass-through,
• fiscal constraints.

Exams may not ask you to cite numbers, but you can connect:

• if external shocks raise import prices, supply-side pressures shift AS and raise inflation.
• if fiscal consolidation reduces AD, output may fall but inflation may also ease.

Your job is to connect the shock type to the correct curve shift and policy response.

Section 5: Exam-Style Problem Solving—Market Models, Quantitative Practice, and South African Institutional Focus by Course Clusters

This final section turns the theory into exam performance: how to plan answers, avoid common traps, and practice with representative question types. It also structures a “cluster” approach focusing on how EKN 320-type content is often delivered across South African universities, colleges, and TVETs through similar course bundles—without inventing specific module codes or claim-by-claim institutional syllabi. Each cluster stays anchored to one institution and its likely course delivery style in the South African higher education ecosystem, while the economic content remains consistent.

Cluster 1 (University of Johannesburg): Economic analysis and applied economics skills integrated into undergraduate and postgraduate economics/management programmes.
Cluster 2 (University of the Witwatersrand): strong emphasis on formal economic reasoning, welfare analysis, and quantitative economic methods in economics and related degrees.
Cluster 3 (University of Pretoria): applied policy evaluation and micro–macro interfaces with clear graph-based and calculation-based assessments.
Cluster 4 (Stellenbosch University): economic theory application with careful interpretation of models and policy consequences.
Cluster 5 (TVET Colleges: e.g., Central Johannesburg TVET College): practical economic analysis and numeracy with case-based questions and applied decision-making.

5.1 Cluster 1: University of Johannesburg—Applied Economic Analysis and Welfare Accounting in Exam Answers

At institutions like the University of Johannesburg (UJ), EKN 320-type content is frequently evaluated through applied reasoning: you must show that you can interpret policy outcomes using standard economic tools.

Likely exam emphases

• Graph correctness and interpretation.
• Welfare accounting (CS, PS, DWL).
• Incidence via elasticity in taxes/subsidies.
• Cost–benefit reasoning with PV/NPV calculations when quantitative components are included.

Exam strategy for welfare and incidence

When answering a tax question, use this sequence:

1. Label baseline equilibrium: (P_0, Q_0).
2. Create the tax wedge: show (P_c) and (P_p) with (P_c – P_p = t).
3. State quantity change: (Q_1 < Q_0).
4. Incidence:
   • Identify whether demand is more inelastic or supply is more inelastic.
   • State “consumers/producers bear more” using elasticity comparison.
5. Welfare:
   • CS decreases.
   • PS decreases.
   • Government revenue = (t \times Q_1).
   • DWL triangle.

A typical UJ-style “show your work” prompt

Prompt type: “A per-unit tax is imposed. Given that demand is more inelastic than supply, explain who bears the tax and draw the welfare effects.”

What gets marks:

• You don’t only state who bears; you explain why using elasticity.
• You identify transfers vs losses.
• You show DWL.

Numeracy link: If the question gives numbers

If the question includes numeric demand and supply (or elasticity values), the best approach is:

• compute equilibrium without tax,
• compute equilibrium with tax,
• then compute PV if the tax is recurring (if asked),
• or compute CS/PS changes using geometric areas (if diagram with numbers is possible).

5.2 Cluster 2: University of the Witwatersrand—Formal Micro and Quantitative Consistency

At the University of the Witwatersrand (Wits), exam questions for economic analysis often demand tighter formal logic—especially around:

• correct use of MR and MC in monopoly,
• correct sign and magnitude in welfare comparisons,
• correct formulation for discounting and expected values.

Formal reasoning that Wits markers reward

1. Correct decision rules
   • Monopoly: (MR = MC).
2. Correct interpretation
   • price from demand at chosen quantity.
3. Consistency
   • if a model assumes no externalities, don’t introduce them mid-answer without stating the change.

Example monopoly question type

Prompt type: “Compare the welfare effects of monopoly vs perfect competition. Include deadweight loss.”

High-scoring response structure:

• State the competitive benchmark: (P = MC) where supply equals demand at efficient quantity.
• Monopoly chooses where (MR = MC) and sets price above marginal cost.
• Show that quantity under monopoly is less than efficient output.
• Explain DWL as the lost surplus from reductions in trades where marginal benefit exceeds marginal cost.

Quantitative practice: discounting with multi-year flows

If given cash flows over multiple years, Wits-style marking often rewards:

• using the correct exponent (t) for each year,
• rounding consistently (or leaving in fractional/approximate form),
• and explicitly stating NPV sign and decision.

5.3 Cluster 3: University of Pretoria—Policy Evaluation and Micro–Macro Integration

The University of Pretoria (UP) style commonly stresses:

• connecting micro mechanisms to macro outcomes (e.g., taxes and inflation, supply-side constraints),
• interpreting policy trade-offs,
• and presenting balanced conclusions grounded in economic logic.

What UP examiners commonly look for

• You identify whether a policy affects private incentives or social welfare directly.
• You discuss time horizons and adjustment costs.
• You show awareness of fiscal/monetary constraints.

Example: VAT-like tax vs externalities

If a question involves broad consumption taxation (e.g., VAT) without externalities:

• DWL can arise due to reduced consumption.
• Government revenue redistributes resources, but efficiency loss remains.

If a question involves taxes to correct negative externalities:

• welfare can improve if tax aligns MSC and MPC.

Your answer must explicitly state which scenario applies.

Macro interface tasks

If asked to interpret a shock in a supply-and-demand framework:

• Identify which curve shifts (AD, AS).
• Explain whether output returns to potential in the long run.
• Discuss policy response and whether it changes inflation dynamics.

5.4 Cluster 4: Stellenbosch University—Graphical Interpretation and Efficiency Claims

At Stellenbosch University (SU), answers often receive high marks for:

• clean graph interpretation,
• consistent use of marginal concepts,
• and careful efficiency/welfare statements.

Graphical discipline checklist

• Curves correctly labeled.
• Equilibrium points marked.
• Distortions shown with wedges or quantity restrictions.
• Welfare triangles and rectangles correctly interpreted:
  • rectangles = transfers,
  • triangles = DWL.

Example: price floor with government intervention

If the government buys the surplus at the floor price:

• show the gap between supply and demand at the controlled price,
• indicate government purchase,
• compute welfare:
  • CS change,
  • PS change,
  • government cost,
  • DWL from reduced mutually beneficial trades.

SU-style grading tends to penalize:

• mixing up “losses” with “transfers.”

5.5 Cluster 5: Central Johannesburg TVET College and TVET Course Style—Case-Based Decision Making and Applied Numeracy

TVET colleges often focus on applied economic analysis, decision-making, and numeracy. Using Central Johannesburg TVET College as an anchor, the exam approach for economic analysis tends to be more case-based and less abstract. However, the economic mechanisms are the same: opportunity cost, incentives, and welfare.

Common question style

• “Interpret this scenario with a demand/supply logic.”
• “Calculate simple PV or compare alternatives.”
• “Explain who benefits and who bears costs.”

Skills to practice for TVET-style assessments

1. Explain incidence in words with one diagram description.
2. Do basic calculations:
   • PV factors,
   • NPV sign decisions,
   • EV if probabilities are given.
3. Use consistent units (rands, percentages, years).

Example case-based tax question

A case might describe a tax on a commodity used in everyday living. Your answer should:

• state that consumers face higher prices,
• show that the effect depends on elasticity,
• and discuss welfare loss from reduced purchases.

If the question includes “low-income consumers,” you must add distributional reasoning:

• even if total surplus falls, policy might still be justifiable depending on equity objectives.
• however, the welfare framework (efficiency and distribution) must be separated.

5.6 High-Yield Exam Questions and How to Answer Them (With Consistent Methods)

This subsection provides “exam-ready” templates you can reuse on test day.

Question Type A: Tax with Elasticity Given (Direction + Incidence + Welfare)

Template answer:

1. Identify baseline (P_0, Q_0).
2. Introduce tax wedge (t) causing consumer price (P_c) and producer price (P_p).
3. Conclude (Q_1 < Q_0).
4. Incidence:
   • If demand is more inelastic: consumers bear more.
   • If supply is more inelastic: producers bear more.
5. Welfare:
   • CS decreases.
   • PS decreases.
   • Government revenue = (t \times Q_1).
   • DWL from reduced quantity.

Add one sentence on transfer vs loss:

• Transfers affect distribution but not efficiency loss; DWL is efficiency loss.

Question Type B: Subsidy and Externality Alignment

Template answer:

1. Explain subsidy reduces wedge and increases quantity.
2. If externality is positive:
   • Market output is below efficient output (MPB < MSB).
   • Subsidy increases private incentives to match MSB, improving efficiency.
3. If no externality:
   • Subsidy increases output beyond efficient level, creating DWL.

Mark-winning point: state clearly which efficient output is relevant.

Question Type C: Monopoly vs Perfect Competition Welfare

Template answer:

1. Competitive equilibrium: (P = MC), efficient quantity (Q_c).
2. Monopoly: choose (Q_m) where (MR = MC), with (Q_m < Q_c).
3. Price: monopoly sets (P_m) from demand at (Q_m), (P_m > P_c).
4. Welfare:
   • DWL due to reduced output.
   • CS decreases; PS increases relative to CS but total surplus decreases.

If a regulated monopoly appears:

• discuss how regulation can aim to replicate efficient output (e.g., price equals MC policies).

Question Type D: NPV with Given Cash Flows

Template answer:

1. Discount each cash flow using (1/(1+r)^t).
2. Compute PV of benefits and costs.
3. Compute (NPV = PV(B) – PV(C)).
4. Decision:
   • NPV > 0 accept; NPV < 0 reject.

If asked to compare:

• use incremental NPV between options, not just raw NPV sums without context.

Question Type E: Expected Value Under Uncertainty

Template answer:

1. List outcomes and probabilities (p_i).
2. Compute expected cash flow (EV = \sum p_i CF_i).
3. If the question asks about risk:
   • mention variance qualitatively unless calculation is requested.

5.7 Practice Set (Representative Numeric Structures Without Over-Random Data)

To build exam readiness, practice the mechanics—even if your exam uses different numbers.

Practice 1: PV and NPV Setup

Given:

• Initial cost at (t=0): R 800,000
• Benefits:
  • (t=1): R 300,000
  • (t=2): R 300,000
• Operating costs:
  • (t=1): R 80,000
  • (t=2): R 90,000
• Discount rate (r = 12%)

Compute:

• (PV_B = \frac{300,000}{1.12} + \frac{300,000}{1.12^2})
• (PV_C = 800,000 + \frac{80,000}{1.12} + \frac{90,000}{1.12^2})
• (NPV = PV_B – PV_C)

Exam technique:

• Keep at least 4 decimals in intermediate steps if you can.
• Round final to nearest rand if instructed.

Practice 2: Incidence Logic Without Full Numbers

Given:

• Demand is more inelastic than supply.

Question:

• “Who bears more of the tax?”

Answer reasoning:

• Inelastic demand: consumers reduce quantity less when price rises.
• Producers can adjust output/price more through elastic supply.
• Therefore, most of the wedge shows as higher consumer price.
• Consumers bear more burden.

Then add welfare:

• DWL depends on quantity reduction, which may be smaller if one side is very inelastic.

Practice 3: Monopoly Output Condition

Question:

• “A monopolist produces where MR = MC. Explain why monopoly output is inefficient relative to competition.”

Answer:

• Competitive efficient output is where price equals marginal cost (P = MC).
• Monopoly sets MR = MC; because MR < P due to downward-sloping demand, the chosen quantity where MR = MC is less than the competitive quantity where P = MC.
• Less output means trades with MB > MC don’t occur, generating deadweight loss.

Final Exam Performance Checklist (Use on the Last Minute)

1. Draw first (if diagram-based). Label everything.
2. Write the mechanism before the conclusion.
   • “Because demand is more inelastic, consumers bear more.”
3. Separate transfers from losses.
4. Use consistent discounting and time indexing for PV/NPV.
5. Keep units consistent (rands, percentages, years).
6. Conclude clearly: welfare improving vs worsening, accept vs reject.
7. Check arithmetic quickly:
   • Does PV decline with time? (It should.)
   • Does NPV sign match intuition? (Not always, but a sign mismatch often indicates a sign error.)

Consolidated “Most Common Mark-Rich Topics” for EKN 320

• Tax/subsidy incidence using elasticity.
• Welfare decomposition: CS, PS, government revenue, DWL.
• Externalities and the alignment of MSC vs MPC or MSB vs MPB.
• Monopoly: MR = MC, price from demand, inefficiency via DWL.
• Discounting, NPV, IRR setup, and consistent real/nominal handling.
• Expected value and risk interpretation.
• Policy evaluation via time horizons and trade-offs in macro contexts.

If you can consistently apply these mechanisms—graphical, quantitative, and welfare-based—you will be able to produce strong EKN 320 exam answers across the full range of typical question styles used in South African economics and economic analysis assessments.