Wec11 Mark Scheme Content Bank

W11-T3-4 | Version 1 — N-Standard | VERIDIAN™

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#Pearson Edexcel IAL Economics WEC11/01

All content derived from published Pearson WEC11 mark schemes 2019–2025. Not affiliated with or endorsed by Pearson Edexcel.

#LEVEL DESCRIPTORS — VERBATIM FROM WEC11 MARK SCHEMES

These are confirmed WEC11 descriptors. They differ slightly from WEC12.

#KAA BAND (essays — 8 marks for 14-mark Discuss / 12 marks for 20-mark Evaluate)

Level 1 (1–3 marks): "Displays isolated, superficial or imprecise knowledge and understanding of economic terms, principles, concepts, theories and models. Use of generic material or irrelevant information or inappropriate examples. Descriptive approach, which has no chains of reasoning."

Level 2 (4–6 marks): "Displays elements of knowledge and understanding of economic terms, principles, concepts, theories and models. Ability to apply knowledge and understanding to some elements of the question. Some evidence and contextual references are evident in the answer. Chains of reasoning in terms of cause and/or consequence are evident but they may not be developed fully or some stages are omitted."

Level 3 (7–8 marks for 8mk KAA / 7–10 for 12mk KAA): "Demonstrates accurate and precise knowledge and understanding of economic terms, principles, concepts, theories and models. Ability to link knowledge and understanding in context using relevant examples which are fully integrated to address the broad elements of the question. Analysis is clear, coherent, relevant and focused. The answer demonstrates logical and multi-stage chains of reasoning in terms of cause and/or consequence."

CONFIRMED DIAGRAM RULE (multiple WEC11 mark schemes): "NB Level 3 response requires a diagram." This appears in every externality, tax, subsidy, and price control essay mark scheme. No diagram = maximum Level 2 KAA regardless of chain quality.

#EVALUATION BAND (essays — 6 marks for Discuss / 8 marks for Evaluate)

Level 1 (1–2 marks): "Evaluative comments are made but there is limited support for those comments. The response is superficial."

Level 2 (3–4 marks / or 3–6 for Evaluate): "Evaluative comments are supported and there is some evidence of reasoned judgement. The answer offers a perspective based on analysis but the conclusion is not conditional."

Level 3 (5–6 marks / or 7–8 for Evaluate): "Evaluative comments are well supported with evidence and show reasoned judgement. An informed judgement is presented. The answer offers a well-reasoned, conditional perspective consistent with the analysis presented."

The critical phrase: "conditional perspective." An unconditional conclusion — "therefore indirect tax is effective" — is Level 2. A conditional conclusion — "indirect tax is effective only if demand is price-elastic" — is Level 3. Identical to WEC12.

#INDIRECT TAX — CONFIRMED INDICATIVE KAA CONTENT

From Oct 2020 Q13, Jan 2021 Q13, Jun 2021 Q13, Oct 2021 Q13, Jan 2022 Q13, Jun 2023 Q13, Jun 2024 Q13, Jun 2025 Q13 mark schemes:

KAA points (any of these earn credit):

Indirect tax → raises production costs → supply curve shifts LEFT (specific tax = parallel shift; ad valorem = pivoting steeper shift)
Price rises from Pe to P1 → quantity falls from Qe to Q1 → consumption of negative externality good falls
Consumer incidence = area between Pe and P1 × Qe (loss of consumer surplus)
Producer incidence = area below Pe (loss of producer surplus)
Government tax revenue = tax × Q1 (rectangle between P1 and Pnet × Q1)
Moves consumption closer to social optimum → reduces welfare loss triangle
External costs fall as quantity of negative externality production/consumption falls
Tax can fund remediation of external costs (NHS spending, environmental cleanup)

Confirmed diagram required:

Supply shifts LEFT from S to S+Tax
New equilibrium at higher P, lower Q
OR: negative externality diagram showing MSC > MPC, welfare loss triangle, social optimum

#NEGATIVE EXTERNALITY — CONFIRMED INDICATIVE KAA CONTENT

From Oct 2019 Q12e, Oct 2020 Q13, Jun 2021 Q13, Oct 2021 Q12e, Jun 2023 Q12e, Oct 2025 Q14 mark schemes:

KAA points:

External costs = negative impact on third parties not involved in the transaction
MSC = MPC + external costs (MSC curve above MPC curve)
Free market produces at Qme where MPB = MPC (private equilibrium)
Social optimum is at Qso where MSB = MSC (lower quantity than market)
Overproduction: Qme > Qso → welfare loss triangle between social optimum and market equilibrium
Third parties bear external costs without compensation — negative impact on welfare
Specific contexts: carbon emissions → global warming → flooding/drought → reduced farm incomes; air pollution → respiratory disease → NHS costs; fertiliser runoff → river contamination → fishing industry losses

Confirmed diagram required (verbatim from mark schemes):

MSC above MPC
Qme above Qso (overproduction shown)
Pme below Pso (price too low at market equilibrium)
Welfare loss triangle between Qso and Qme

#POSITIVE EXTERNALITY / SUBSIDY — CONFIRMED INDICATIVE KAA CONTENT

From Jan 2019 Q13, Jan 2021 Q13, Jan 2022 Q14, Jan 2023 Q14, Jun 2023 Q14, Jan 2024 Q14, Jun 2024 Q13 mark schemes:

KAA points:

External benefits = positive impact on third parties not involved in the transaction
MSB = MPB + external benefits (MSB curve above MPB curve)
Free market produces/consumes at Qme where MPB = MPC (private equilibrium)
Social optimum at Qso where MSB = MSC (higher quantity than market)
Underconsumption: Qme < Qso → welfare loss triangle → too little of the good produced/consumed
Subsidy → supply shifts RIGHT → price falls from Pe to P1 → quantity rises from Qe to Q1 → consumption rises toward social optimum
Consumer surplus increases; producer surplus increases; government pays cost of subsidy
From Jan 2024 subsidy mark scheme: "Subsidy is €400 → reduces cost of production → supply shifts right → price falls from Pe to P1 → quantity increases from Qe to Q1 → consumer surplus increases from PeEF to P1CF"

Diagram confirmed from Jun 2024 mark scheme (BEB subsidy):

Supply shifts right (S to S+Subsidy)
Price falls Pe to P1
Quantity rises Qe to Q1
Consumer surplus: PeEF → P1CF (increase shown)
Producer surplus: PeEG → P1CH (increase shown)
Government cost: ACP1P2 area

#GOVERNMENT FAILURE — CONFIRMED INDICATIVE KAA CONTENT

From Oct 2019 Q13, Jun 2022 Q13, Oct 2023 Q13, Oct 2025 Q14 mark schemes:

Definition (verbatim from Jan 2020 examiner report): Government failure occurs when government intervention leads to a net welfare loss or a misallocation of resources. This must be explicit in the definition — "government doing bad things" alone = zero.

KAA points:

Unintended consequences: tax on imported cars → smuggling → tax revenue lost AND black market activity increases — net welfare loss from additional crime/safety risks
Information gaps: regulator lacks sufficient information to set optimal tax/price → tax either too high (over-correction, excess burden) or too low (under-correction, welfare loss persists)
Regulatory capture: regulatory agency advances interests of regulated firms rather than public — intervention fails to correct market failure
Administrative costs: cost of implementing/enforcing intervention may exceed welfare gain
Moral hazard from intervention: tax on negative externality may create perverse incentive if firms find cheaper route (smuggling, regulatory arbitrage)

The key evaluation condition: "Government failure holds only if the intervention is poorly calibrated — if the tax equals the exact marginal external cost (Pigouvian tax), government failure does not occur. The information gap that prevents accurate calibration is the binding constraint."

#INFORMATION ASYMMETRY / IRRATIONAL BEHAVIOUR — CONFIRMED KAA CONTENT

From Jan 2020 Q14, Oct 2020 Q14, Jan 2021 Q14, Oct 2023 Q14, Oct 2024 Q13, Jun 2025 Q14 mark schemes:

Information asymmetry KAA:

Asymmetric information: seller knows more than buyer (or vice versa) → buyer cannot make informed rational decision
Underconsumption of healthcare/insurance: individuals underestimate probability of illness → purchase insufficient coverage → market equilibrium below social optimum
Moral hazard (from Jan 2021 Q9, confirmed in mark scheme): insured individuals take more risks because costs borne by insurer → higher claims than predicted → adverse selection (high-risk individuals buy insurance, low-risk opt out) → market fails
Adverse selection: high-risk customers disproportionately purchase insurance → insurer cannot price efficiently → market may collapse (Akerlof market for lemons)

Irrational behaviour KAA:

Bounded rationality: individuals lack information or cognitive capacity to process all relevant information → decisions deviate from rational utility maximisation
Herding: individuals follow others' behaviour rather than own information → collective irrationality → under/overconsumption
Status quo bias: habitual behaviour means people do not switch to better alternatives even when available → underconsumption of better products/services
Present bias: individuals over-weight present consumption and under-weight future benefits → underconsumption of education, health insurance, pensions

#PRICE MECHANISM / MAX-MIN PRICES — CONFIRMED KAA CONTENT

From Jun 2020 Q13, Jun 2021 Q14, Jun 2022 Q13, Jan 2024 Q13 mark schemes:

Maximum price (price ceiling — set BELOW equilibrium):

Price ceiling at Pmax < Pe → quantity demanded extends (Qd > Qe) → quantity supplied contracts (Qs < Qe) → excess demand / shortage (Qd - Qs)
Consumer surplus may increase for those who can access the good at lower price
Producer surplus falls → supply may fall further over time
Black market may emerge at price above maximum → unintended consequence / government failure risk
Confirmed context: housing market maximum rent, food price ceilings

Minimum price (price floor / guaranteed price — set ABOVE equilibrium):

Minimum price at Pmin > Pe → quantity supplied extends (Qs > Qe) → quantity demanded contracts (Qd < Qe) → excess supply / surplus (Qs - Qd)
Government must purchase surplus to maintain the minimum price → fiscal cost
Producer surplus increases (those who sell at higher price benefit)
Consumer surplus falls (higher price reduces consumer access)
Confirmed context: agricultural minimum prices, minimum alcohol price

#ELASTICITY CALCULATIONS — CONFIRMED SECTION B CONTENT

PED formula (confirmed across all series): PED = % change in quantity demanded / % change in price

YED formula (confirmed Jan 2020 Q10 — common error identified): YED = % change in quantity demanded / % change in income NOT: % change in income / % change in quantity demanded Examiner report confirmed: inverting is the most common YED error

XED formula: XED = % change in quantity demanded of good A / % change in price of good B

Positive XED = substitutes
Negative XED = complements
Zero XED = unrelated goods

Tax incidence formula: Consumer incidence = price rise × new quantity (rectangle from Pe to P1 × Q1) Producer incidence = price fall received × new quantity (rectangle from Pe to Pnet × Q1)

Common calculation errors from examiner reports:

YED: inverting numerator and denominator (Jan 2020)
XED: confusing with YED formula (Jan 2021)
Percentage point vs percentage change: subtract for pp, formula for % (Jun 2022 Q8)
Adding % sign to elasticity values: elasticities have no % sign (Jan 2020)

#THE CONTEXT CEILING RULE — WEC11 CONFIRMED

Identical to WEC12. Verbatim from multiple WEC11 mark schemes:

"Ability to link knowledge and understanding in context using relevant examples which are fully integrated to address the broad elements of the question."

Without extract data or own-knowledge context embedded in the chain: maximum Level 2 KAA. The context must be INTEGRATED — not mentioned in the introduction and then abandoned.

WEC11-specific application: Context is typically the specific product in the extract (tobacco, petrol, vaccination, electric vehicles). Using figures from the extract (e.g. "a ten-fold increase in fertiliser use between 1960 and 2019") is what earns the application mark — not just naming the product.

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