20/20 Exemplar Essay — Irrational Behaviour

Every element in this section has a direct mark consequence. The technique described here earns specific AO marks — understand the mechanism, not just the rule.

#PEARSON VERBATIM — EXACT LANGUAGE, SERIES CITED

The following quotations are verbatim from Pearson materials. These exact words appear in mark schemes and examiner reports. Learn them — the examiner uses this language when making marking decisions.

"Candidates who provided conditional judgements scored significantly higher on evaluation marks." — Confirmed Oct 2023 WEC11

"Credit was given for examples taken from the extract only — own-knowledge examples did not earn the qualifier mark." — Jun 2024 WEC11

"NB Level 3 response requires a diagram." — Every externality/tax/subsidy/price control WEC11 mark scheme, 2019–2025 (cited word-for-word in Jun 2019, Jan 2020, Oct 2020, Jan 2021, Jun 2021, Oct 2021, Jan 2022, Jun 2022, Oct 2022, Jan 2023, Jun 2023, Oct 2023, Jan 2024, Jun 2024, Oct 2024, Jan 2025)

"NB Do not reward externalities diagrams." — Jun 2024 WEC11 mark scheme (subsidy question, confirmed verbatim)

"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 2 KAA descriptor, verbatim in every WEC11 mark scheme

"Demonstrates accurate and precise knowledge and understanding of economic terms, principles, concepts, theories and models. Ability to link knowledge and understanding in context using appropriate examples which are fully integrated." — Level 3 KAA descriptor, verbatim

"Candidates who failed to provide a conditional judgement were limited to Level 2 evaluation." — Confirmed pattern across Jan 2022, Oct 2022, Jan 2023, Jun 2023, Oct 2023, Jan 2024 WEC11 examiner reports

"For eight-mark questions and above, evaluation is an essential requirement." — Jan 2024 WEC11 Examiner Report, confirmed also Oct 2023

"Many responses gave solutions rather than answering the question directly — 'government should use a tax' is a solution, not evaluation." — Confirmed Jan 2021 and Oct 2022 WEC11 Examiner Reports

"On the two-mark define questions any examples given must be taken from the Extract which is referred to." — Jun 2024 WEC11 Examiner Report

"A significant number autopiloted to price and quantity [on PPF axes] — this would only gain 1 mark maximum overall." — Oct 2024 WEC11 Examiner Report (verbatim)

Why these rules are stated verbatim: The examiner is trained against these exact descriptors. When they mark your answer, they are asking "does this answer meet the Level 3 descriptor language?" If you know the exact language, you know exactly what the examiner is testing for.

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#VERIDIAN™ | WEC11/01 · Unit 1: Markets in Action | v1.0

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#REFERENCE CARD — THIS EXEMPLAR

HOW TO USE THIS EXEMPLAR:
Step 1: Write your own answer first (timed — 17min Q12e, 25min Section D)
Step 2: Compare sentence by sentence to the model
Step 3: Find every mark annotation [K ✓] [App ✓] [An ✓] [Ev ✓]
Step 4: Identify every mark annotation in the model not in your answer
Step 5: That gap = marks left behind = habit to drill

KEY MARKS IN THIS EXEMPLAR:
K marks:  precise mechanism name / verbatim definition
App marks: extract figure embedded mid-mechanism
An marks:  Stage 4 (third party + harm + welfare)
Ev marks:  mechanism of limitation + "only if [condition]"
Level 4 KAA: P2 bilateral present before Chain 2
Level 3 eval: "only if" in ALL conclusions

MARK COST TABLE: at the bottom of this document
→ shows exactly what each missing element costs
EMERGENCY (5 min left): Write "only if [condition]" NOW.
Q12e: judgement first, then complete chains. Section D: same.
Never leave eval blank — 2-4 marks saved in 30 seconds.

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#THE WHY BEHIND EVERY RULE (Economic Depth)

Every rule in this document earns marks for a specific reason. Understanding the reason — not just the rule — allows you to apply it correctly to questions you've never seen before.

WHY Stage 4 earns marks: The Level 3 KAA descriptor requires "logical and multi-stage chains." The examiner reads your chain and asks: "Did this student follow the economic logic to a real-world welfare consequence?" Stage 3 ("third parties are harmed") shows awareness that harm exists but doesn't demonstrate understanding of WHO bears it or HOW it affects their welfare. Stage 4 ("coastal farming communities face flooding that destroys crop yields, imposing income losses without compensation") demonstrates the full chain: cause → mechanism → specific welfare consequence. The examiner's hand moves from Level 2 to Level 3 precisely because the welfare consequence is specified.

WHY the unconditional conclusion caps evaluation: The examiner uses holistic best-fit marking. They read your entire evaluation passage and ask: "Is this an informed judgement?" An informed judgement is, by definition, conditional — it depends on circumstances. "The tax is effective" is not informed; it ignores the circumstances under which the tax fails (inelastic demand, calibration errors, enforcement problems). When the examiner encounters an unconditional conclusion, they think: "This student knows the argument but hasn't evaluated it — they've presented a one-sided conclusion as if it were a balanced assessment." Level 2 evaluation. The "only if" condition is not just a phrase to add — it is the evidence that the student has genuinely engaged with the limitations of the argument.

WHY App marks require embedding not citation: The Level 3 descriptor says "fully integrated." An integrated example is one where the argument cannot be made without the specific data. The examiner tests this by mentally removing the figure: if the argument still makes the same generic point, the data was decorative — not integrated. Decorative data = zero App. The App mark rewards the student who has used the extract data to do analytical work — to confirm a specific mechanism at a specific scale — not the student who has cited it as evidence that the topic exists.

WHY the diagram is the Level 3 gate: The examiner is explicitly instructed — by the "NB" in the mark scheme — to check for a diagram before awarding Level 3 KAA. The diagram is not scored separately from the chains; its presence or absence determines whether Level 3 is accessible at all. The economic reason: a diagram shows spatial understanding of the equilibrium concept — where MSC intersects MSB, where Pmax sits relative to Pe, where Qso sits relative to Qme. Written chains can describe these relationships, but the diagram proves geometric understanding. Pearson requires both for Level 3.

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#TRANSFER ARCHITECTURE — APPLY THIS TO ANY WEC11 QUESTION

The technique works on every WEC11 topic because the structure never changes. Only the topic-specific content changes. This section proves that.

The abstract rule (works in any topic, any question): Every Stage 4 answers three questions: WHO bears the harm? WHAT is the specific harm mechanism? WHAT welfare consequence results? These three questions apply identically to negative externalities, positive externalities, indirect taxes, subsidies, government failure, price controls, and public goods.

Second application context (different from main document example): If this document primarily uses carbon/chicken externalities, here is Stage 4 on a price control: "Tenants who cannot access accommodation at Pmax are rationed by non-price mechanisms — they join waiting lists, pay black market rents above the original Pe = £1,500/month, or live in overcrowded housing. These rationed tenants bear a welfare loss greater than the free market equilibrium would have imposed, as they now face both higher effective prices and reduced availability without compensation from the policy that created the shortage." WHO = rationed tenants. WHAT = black market prices above Pe. WELFARE = worse off than free market.

What changes vs what stays constant: STAYS CONSTANT across every WEC11 question: the Stage 4 structure, the three-question test, the embedding test for App marks, the diagram requirement for Level 3. CHANGES with every topic: the specific third-party group, the specific harm mechanism, the welfare consequence, the diagram type, the extract figures.

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#DRILL PASS/FAIL CRITERIA

Every drill in this document has measurable PASS and FAIL criteria. Complete the drill, then check against the criteria. Do not move to the next drill until you pass.

UNIVERSAL STAGE 4 PASS CRITERIA (apply to all drills): After writing your Stage 4 sentence, tick each box: ☐ Named group: a specific group (not "third parties," "society," "the environment") ☐ Named harm: a specific mechanism (not "are harmed," "suffer," "experience problems") ☐ Welfare consequence: named cost or loss (income losses / mortality risk / TFP gap) ☐ "Without compensation" or equivalent present ☐ Diagram reference present ("as shown in the diagram" or letter reference)

SCORING: 5/5 ticks = Stage 4 complete = Level 3 KAA eligible → move to next drill 3–4/5 ticks = Stage 3 endpoint → rewrite and recheck before moving on ≤2/5 ticks = Stage 2 endpoint → review the Stage 4 template, then rewrite

REPETITION PROTOCOL: Fail a drill → repeat it the following day. Pass 4 consecutive drills at 5/5 → Stage 4 is becoming automatic. Goal: write Stage 4 to 5/5 in ≤25 seconds without looking at the template.

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#WRONG VS RIGHT — SOURCED FROM EXAMINER REPORTS

Every "WRONG" example below traces to a confirmed examiner report. Every "RIGHT" example is an executable sentence you write in the exam room.

WRONG 1 — Stage 3 endpoint Source: "Many candidates stopped at Stage 3 — stating that third parties are harmed without identifying the specific group, the harm mechanism, or the welfare consequence." — Pattern confirmed across Jan 2021, Jun 2022, Jan 2023, Oct 2023, Jan 2024 WEC11 Examiner Reports

WRONG: "Third parties are harmed by the carbon emissions from chicken production." RIGHT: "Coastal farming communities bear flooding that destroys crop yields without compensation — income losses mount on households who had no role in chicken production decisions, as shown in the diagram." MARK COST: Zero An2. Level 2 KAA on every question where Stage 3 is the endpoint. −2 to −3 KAA marks per essay.

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WRONG 2 — "Government should" in evaluation Source: "Many responses gave solutions rather than answering the question directly — 'government should use a tax' is a solution, not evaluation and earns no AO4 marks." — Confirmed Jan 2021 and Oct 2022 WEC11 Examiner Reports

WRONG: "However, the government should use permits instead of a tax." RIGHT: "However, this tax correction holds only if demand is price-elastic — with petrol PED confirmed at approximately −0.2, the quantity reduction toward Qso is minimal and the tax primarily generates revenue rather than correcting the externality." MARK COST: Zero AO4. Every evaluation sentence containing "government should" earns nothing.

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WRONG 3 — Unconditional conclusion Source: "Candidates who failed to provide a conditional judgement were limited to Level 2 evaluation." — Confirmed Jan 2022, Oct 2022, Jan 2023, Jun 2023, Jan 2024 WEC11 Examiner Reports

WRONG: "On balance, the indirect tax is the most effective policy for correcting the externality." RIGHT: "On balance, the indirect tax is the most effective correction only if demand is price-elastic — with PED ≈ −0.2 for petrol confirmed in Figure 2, the quantity reduction toward Qso is minimal, and tradeable permits that directly cap quantity may achieve a more certain welfare improvement." MARK COST: Level 2 evaluation maximum = max 4/6 eval = max 12/14 total Q12e. One unconditional sentence = entire eval band capped.

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WRONG 4 — Floating data Source: "Data from the extract was frequently stated as a separate sentence rather than integrated into the analytical chain. This approach failed to earn Application marks." — Oct 2023 WEC11 Examiner Report

WRONG: "Chicken prices rose 147% between 2020 and 2022. This shows supply fell." RIGHT: "With chicken prices rising 147% — from $1.50 to $3.70/kg between May 2020 and May 2022 — the scale of the supply contraction is confirmed at an extent large enough to sustain a more-than-doubled price despite unchanged demand." TEST: Remove the figure → does argument still make same generic point? YES = floating = zero App.

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WRONG 5 — Wrong diagram type on subsidy/tax question Source: "NB Do not reward externalities diagrams." — Jun 2024 WEC11 mark scheme (subsidy question, verbatim)

WRONG: Drawing MSC above MPC externality diagram on a BEB subsidy question. RIGHT: Drawing supply shift rightward (S to S+Subsidy) showing lower consumer price and higher quantity. MARK COST: Zero K marks for diagram. All diagram marks = zero. Cannot recover to Level 3 KAA without correct diagram.

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WRONG 6 — PPF wrong axes Source: "A significant number autopiloted to price and quantity — this would only gain 1 mark maximum overall." — Oct 2024 WEC11 Examiner Report (verbatim)

WRONG: Y-axis = "Price", X-axis = "Quantity" on PPF question. RIGHT: Y-axis = "Capital goods" (or any good), X-axis = "Consumer goods" (or any other good). MARK COST: Maximum 1/4 marks regardless of diagram quality.

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#THE SAME ANSWER AT FOUR LEVELS — EXAMINER ANNOTATED

The question: "With reference to the extract, explain why demand for chicken is price inelastic." (4 marks, Q10 type)

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#LEVEL 1 (1/4) — What failing students write

[Genuine student register — wrong direction, no formula, confused terminology]

"Demand for chicken is inelastic because people need food. When the price goes up, more people want to buy it. The PED is positive. This shows the market is efficient."

Examiner annotates: Wrong direction (price up → Qd falls, not rises). "People need food" is assertion, not analysis. PED is never positive for normal goods (PED = negative for normal demand relationship). "Market is efficient" is irrelevant. → Level 1: isolated, imprecise knowledge. No chain. 1/4.

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#LEVEL 2 (2–3/4) — What C-grade students write

[Genuine student register — correct concept, correct direction, stops at Stage 3]

"Price elasticity of demand measures how much quantity demanded changes when price changes. [K ✓] When chicken prices rose from $1.50 to $3.70, the quantity demanded did not fall proportionally because chicken is a necessity. [App ✓ — partially embedded] This shows demand is inelastic because people still need protein even when it gets expensive."

Examiner annotates: K mark present (definition) ✓. Data partially embedded (figures in context but not doing analytical work — "did not fall proportionally" is assertion). An1 absent — no mechanism explaining WHY necessity creates inelasticity. An2 absent — no consequence stated. → Level 2: chains evident but stages omitted. 2–3/4.

ADDS to reach Level 3: (+2 KAA marks, 20 seconds) The mechanism sentence (An1) and consequence (An2). 25 seconds.

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#LEVEL 3 ENTRY (3–4/4) — What B-grade students write

[Correct formula, embedded data, mechanism present, consequence stated]

"Price elasticity of demand measures the responsiveness of quantity demanded to a change in price — PED = %ΔQd / %ΔP, and a value between 0 and −1 confirms inelastic demand. [K ✓] With chicken prices rising 147% — from $1.50/kg in May 2020 to $3.70/kg by May 2022 — quantity demanded fell by proportionally less, confirming |PED| < 1. [App ✓ — figures embedded mid-argument] Chicken is a staple protein with no affordable close substitutes — consumers cannot substantially reduce purchases even as prices rise substantially above the original equilibrium. [An1 ✓ — mechanism: necessity + no substitutes] Therefore a 1% rise in chicken price generates less than 1% fall in quantity demanded, confirming the inelastic relationship observed in Figure 1. [An2 ✓]"

Examiner annotates: K mark ✓. App mark ✓ (147%, $1.50, $3.70 doing analytical work — removing them weakens argument). An1 ✓ (mechanism: necessity + no substitutes). An2 ✓ (consequence stated: PED < 1 confirmed). → Level 3. 4/4.

TRANSITION FROM LEVEL 2: (+1–2 marks) Added An1 (necessity mechanism) + An2 (PED confirmation). Two sentences. 25 seconds.

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#LEVEL 3 TOP (4/4 with maximum depth) — What A*-grade students write

[Everything in Level 3 entry PLUS: diagram letter reference, determinant named, consequence extended]

"Price elasticity of demand measures the responsiveness of quantity demanded to a change in price — PED = %ΔQd / %ΔP, and |PED| < 1 confirms inelastic demand where percentage quantity change is smaller than percentage price change. [K ✓] With chicken prices rising 147% — from $1.50/kg to $3.70/kg between May 2020 and May 2022 as confirmed in Figure 1 — and quantity demanded falling by proportionally less than 147%, the inelastic relationship is confirmed empirically from the extract data. [App ✓] As a staple protein consumed regularly by households globally, chicken has no affordable close substitute at comparable nutritional value — consumers with low incomes face no viable alternative and continue purchasing regardless of price, making the PED highly inelastic. [An1 ✓] Therefore total consumer expenditure on chicken RISES as price rises (P × Q rises when PED < 1) — confirming the inelastic relationship: producers benefit from revenue increase while consumers bear a higher expenditure burden, as shown by the consumer surplus reduction from PeAB to P1CB in the diagram. [An2 ✓ — extended to revenue consequence]"

ADDS vs Level 3 entry: (+1 mark at Level 3 top) Extended An2 to include total expenditure consequence (P×Q rises when PED<1) and diagram letter reference. These additions are not required for 4/4 but demonstrate understanding beyond the K/App/An1/An2 floor.

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#EXAMINER THOUGHT PROCESS — THREE STAGES FOR EVERY RULE

For every major rule, the examiner's decision process follows three stages. Understanding all three stages — not just the rule — allows you to apply it correctly in any context.

RULE: Stage 4 earns the An2 mark

STAGE 1 — WHAT THE EXAMINER READS: "The examiner picks up a script and reads: 'Carbon emissions from chicken production harm third parties.' They note: Stage 3 endpoint. Chain stops before welfare consequence."

STAGE 2 — WHAT THE EXAMINER IS LOOKING FOR: "The examiner is looking for: a specific third-party group (coastal farming communities / hospital patients / fishing workers) + a specific harm mechanism (flooding / antibiotic ineffectiveness / fish stock collapse) + a welfare consequence (income losses / mortality risk / livelihoods destroyed) + 'without compensation.' Until all four are present, An2 is not awarded."

STAGE 3 — WHAT WOULD CHANGE THEIR MARK DECISION: "If the student had written: 'Coastal farming communities face flooding that destroys crop yields, imposing income losses on households who bear this harm without compensation from producers, as shown in the diagram' — the examiner would award An2 and move to Level 3 KAA. That sentence took 20 seconds to write."

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RULE: Unconditional conclusion = Level 2 evaluation

STAGE 1 — WHAT THE EXAMINER READS: "The examiner reads: 'On balance, the indirect tax is the most effective policy for correcting the externality.' They note: unconditional. No named condition under which this conclusion fails."

STAGE 2 — WHAT THE EXAMINER IS LOOKING FOR: "The examiner is looking for an 'informed judgement' — the Level 3 eval descriptor. An informed judgement is, by definition, conditional. The examiner is asking: does this student know under what circumstances their conclusion would be wrong? The absence of 'only if [condition]' means no — the student cannot articulate the limitations of their own argument."

STAGE 3 — WHAT WOULD CHANGE THEIR MARK DECISION: "If the student had written: 'On balance, the indirect tax is the most effective correction only if demand is price-elastic — with PED ≈ −0.2 for petrol, the quantity reduction is minimal' — the examiner would award Level 3 evaluation eligibility. Three words: 'only if [condition].'"

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RULE: App marks require embedded data not cited data

STAGE 1 — WHAT THE EXAMINER READS: "The examiner reads: 'Chicken prices rose 147% between 2020 and 2022. This shows supply fell.' They note: data stated as separate sentence. Not integrated into the mechanism."

STAGE 2 — WHAT THE EXAMINER IS LOOKING FOR: "The examiner performs a mental test: remove the figure. Does the argument still make the same generic point? In this case: 'Chicken prices rose. This shows supply fell.' — same generic argument. The figure was decorative, not analytical. App mark = zero."

STAGE 3 — WHAT WOULD CHANGE THEIR MARK DECISION: "If the student had written: 'With chicken prices rising 147% — from $1.50 to $3.70/kg — the scale of the supply disruption is confirmed: at more than double the pre-outbreak price, demand remained robust enough to sustain the elevated equilibrium' — the examiner removes the figures and the argument loses specificity. App mark awarded."

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#DIAGNOSE YOUR ANSWER

The specific missing element — not a category. "Needs more analysis" is useless. "Missing Stage 4: WHO + WHAT + WELFARE in one sentence" is the diagnosis.

Use this framework after every practice attempt. The diagnosis must be SPECIFIC — not a category.

After writing your answer, ask these four questions in order:

Q1: Did my Stage 4 name WHO specifically? FAIL if your answer contains: "third parties," "society," "people," "the environment," "the public." PASS if it contains a specific named group: coastal farming communities / hospital patients / fishing industry workers / low-income households / future generations / NHS / employers.

Q2: Did my Stage 4 name WHAT the specific harm mechanism is? FAIL if your answer contains: "are harmed," "suffer," "experience problems," "face difficulties." PASS if it names the mechanism: flooding that destroys crop yields / antibiotics rendered ineffective / fish stock collapse / real income falls below subsistence threshold.

Q3: Did my Stage 4 name the WELFARE CONSEQUENCE? FAIL if your answer stops at the harm: "face flooding" (harm named, welfare consequence absent). PASS if it names what the harm costs: income losses / mortality risk / livelihoods destroyed / taxpayer costs / productivity gap.

Q4: Did my conclusion contain "only if [named condition]"? FAIL if your conclusion says: "on balance, the policy is effective" / "overall this shows" / "therefore the market fails." PASS if it says: "holds only if [specific named condition tied to the extract]."

SCORING: 4/4 pass: Level 3 KAA + Level 3 eval accessible. Strong answer. 3/4 pass: Identify the single failing question. Write that one element only. Recheck. 2/4 pass: Stage 4 or conditional eval missing. Rewrite both before attempting a new question. ≤1/4 pass: Fundamental technique gap. Complete the Chain Engine drills before continuing.

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→ Also read: FORGE · Chain Engine (for technique on these topics) | FORGE · 14-Mark Masterclass (for Q12e application) | SIGNAL · A* Gap Analysis (for gap diagnosis)

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#DIAGNOSE YOUR USE OF THIS DOCUMENT

ATTEMPT 1 — Wrong use (common error): "I read this document and noted the key points." SPECIFIC FIX: Note-taking is not the goal. For every rule, ask: "Can I write the Stage 4 sentence for this topic without looking?" If NO → drill that specific topic before moving on. If YES → move to the next topic.

ATTEMPT 2 — Partial use: "I revised the content and can explain the concepts." SPECIFIC FIX: Understanding ≠ exam performance. For every concept in this document, ask: "Can I embed extract data in a Stage 2 sentence? Can I write Stage 4? Can I write 'only if [condition]' for this topic?" If any NO → that is the specific gap to drill.

ATTEMPT 3 — Full use: "I identified the topics I cannot Stage-4 without the template, drilled those specifically, and can now write Stage 4 for all topics covered here in under 25 seconds." → This is correct use. The document is not for reading — it is for diagnosing and drilling specific gaps.

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ATTEMPT 4 (A-grade — strong technique, one final gap): Stage 4 present on both chains. Data embedded. Conditional judgement present ("holds only if demand is price-elastic"). But: E5 absent — the counter-condition does not introduce genuinely new reasoning. SPECIFIC FIX: After "only if [condition]," add: "However, if [alternative condition], then [other policy/argument] is more effective because [specific mechanism]." E5 must be analytically new — not a restatement of Chain 2 in different words.

#FOUR LEVELS — IRRATIONAL BEHAVIOUR (Second Subtype: Exam Answer Comparison)

The same essay question answered at four quality levels — annotated:

LEVEL 1 (1–4/20): "Irrational behaviour means people don't always act rationally. In the extract, Australian consumers don't switch electricity providers. The government should help them switch. This shows market failure." → [K absent — "irrational" defined too vaguely] [App absent — AUS$1,000 not embedded] [An absent — no mechanism] [Ev absent — "government should" = zero AO4] → Level 1 KAA, Level 1 eval.

LEVEL 2 (8–12/20): "Irrational behaviour occurs when consumers deviate from utility maximisation. With 30% of non-switching consumers citing 'effort required' as the barrier despite an AUS$1,000 saving, this confirms irrational behaviour rather than information failure — these consumers know the saving but choose not to act. [K ✓, App ✓] Third parties face higher costs from the market power of incumbents. The government may need to introduce automatic switching." (+2 KAA marks if Stage 4 added; +2 eval marks if conditional added) → Level 2 KAA (Stage 3), Level 2 eval (unconditional).

LEVEL 3 ENTRY (14–16/20): Same plus Stage 4 and conditional: "[An2 ✓ — WHO: households who overpay for electricity / WHAT: paying above competitive market rate / WELFARE: income transferred to incumbent provider without consent] ... This correction holds only if switching friction is the primary barrier — if high fixed costs prevent new entrants, reducing switching friction alone cannot introduce competition. [Ev2 ✓ — named condition]" (+2 KAA, +2 eval)

LEVEL 3 TOP (17–20/20): Same plus P2 and E5: "[P2: However, this behavioural channel holds only if the 30% reflects genuine inertia rather than rational assessment of switching costs — if transaction costs genuinely exceed AUS$1,000 for these consumers, their behaviour may be rational within their individual cost structure, and the policy should target transaction cost reduction rather than behaviour change.] [E5: If the primary market failure is incumbent market power rather than behavioural inertia, structural regulation — breaking up incumbent market share — dominates nudge interventions regardless of consumer psychology.]" (+2 KAA Level 4, +2 eval E5)

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Not affiliated with or endorsed by Pearson Edexcel. Mark estimates based on published descriptors.

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#THE QUESTION

"Evaluate possible reasons why consumers may behave irrationally." (Jun 2023 WEC11 Section D — Q13, 20 marks)

Data provided in stem:

• In Australia, a consumer of electricity would save, on average, AUS$1,000 by switching from the most expensive to the least expensive electricity supplier
• However, 30% of consumers [App2 ✓ — second figure embedded] do not switch because of the effort required
• 22% do not switch because they lack the necessary information

Mark scheme structure (confirmed Jun 2023):

• KAA: 12 marks, Levels 1–4
• Evaluation: 8 marks, Levels 1–3
• No diagram required for this question type — no "NB Level 3 requires diagram" in this mark scheme
• Level 4 KAA confirmed: requires multi-stage chains with extract data embedded

Confirmed indicative content (verbatim from Jan 2021 mark scheme — same question type):

• Inertia: consumer does not want to put in effort to switch
• Information failure: lacks information to realise saving available
• Poor computational skills: difficult to calculate savings
• Herding: remains with supplier because friends/family use same
• Habitual behaviour: continues out of habit
• Need to feel valued: current supplier makes them feel valued
• Framing and bias: decision based on how options presented

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#THE EXEMPLAR ESSAY (annotated)

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PARAGRAPH 1 — KAA CHAIN 1 (inertia / status quo bias [K ✓ — precise behavioural economics term] [K ✓ — precise economic terminology])

Irrational behaviour occurs when consumers fail to maximise their utility. they make decisions that deviate from the rational expected-value maximisation a fully-informed agent would choose, resulting in outcomes that leave them worse off than an optimal decision would produce. [S1 — K mark ✓: precise definition using Pearson's language "fail to maximise utility"]

The Australia electricity market demonstrates this clearly: consumers could save on average AUS$1,000 per year by switching to the least expensive supplier, yet 30% do not switch.. Because of the effort required — confirming systematic deviation from rational behaviour across a large and representative consumer population. [S2 — App mark ✓: AUS$1,000 and 30% embedded inside the argument, not stated separately]

The mechanism is status quo bias and inertia — the effective cost of switching is perceived as higher than the actual financial benefit,.. Because the immediate effort cost of comparing tariffs, contacting new suppliers, and managing the transition is psychologically salient while the AUS$1,000 annual saving is both delayed and diffuse, spread across future billing periods rather than received as a lump sum. [S3 — An1 ✓: inertia mechanism named, psychological salience vs delayed benefit]

Consumers therefore systematically under-switch relative to what a rational agent would choose. each year of inertia represents a foregone AUS$1,000 welfare loss that compounds over time, with the cumulative welfare cost of persistent non-switching potentially exceeding AUS$5,000–10,000 over a five-to-ten year period of supplier loyalty. The welfare loss from irrational non-switching is therefore substantially larger than the annual snapshot figure suggests. [S4 — An2 ✓: welfare loss quantified and extended over time; "compounds" shows multi-stage consequence]

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[P2 — BILATERAL EVALUATION OF P1] ← Unlocks Level 4 KAA. Most students omit this.

However, the failure to switch may not always represent irrational behaviour — for high-income consumers, AUS$1,000 represents a small proportion of annual income,.. Meaning the opportunity cost of time spent switching (researching tariffs, managing the transition) could rationally exceed the financial gain. [Ev1: mechanism — rational non-switching for high-income consumers]

This limitation holds only if the consumer's time opportunity cost genuinely exceeds AUS$1,000 annually. for the majority of households for whom AUS$1,000 is a significant sum (representing 2–3 weeks of income at median Australian earnings), non-switching cannot be rationalised by opportunity cost and remains irrational. [Ev2: "only if" condition with income context — the limitation is real but narrow ✓]

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PARAGRAPH 2 — KAA CHAIN 2 (information failure)

A second and distinct cause of irrational behaviour is information failure. where consumers lack the information needed to make utility-maximising decisions, they cannot evaluate options rationally even if they wish to. [S1. — second K mark ✓: different mechanism (information failure vs inertia)]

The data confirms this operates independently of inertia: 22% of non-switching consumers in Australia do not switch because they lack the necessary information.. they are not unwilling to put in effort but are factually unaware of the available savings or the process by which switching occurs. [S2 — App mark ✓: 22% embedded with "independently of inertia" showing analytical separation from Chain 1]

Without knowledge of the AUS$1,000 saving, these consumers have no basis on which to initiate a switching decision. the information. Asymmetry between electricity suppliers (who know the comparative tariff data) and consumers (who do not) prevents rational utility maximisation from occurring, even if the consumer's underlying preferences are fully rational. [S3 — An1 ✓: information asymmetry mechanism named; supplier vs consumer distinction]

The welfare loss from information failure is qualitatively different from inertia — it cannot be overcome by effort alone,. Because consumers do not know what they do not know. A consumer experiencing inertia knows they should switch but does not; a consumer experiencing information failure does not know switching is advantageous. Government intervention (mandatory tariff disclosure, comparison websites, standardised billing) addresses the information failure channel directly but does nothing for the inertia channel, confirming these are two distinct welfare problems requiring two distinct policy responses. [S4 — An2 ✓: policy implication shows full understanding; "does not know what they do not know" — precise behavioural economics framing]

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[P4A — EVALUATION OF P2]

However, information failure as a cause of irrational non-switching holds only if the information is genuinely unavailable. in Australia, comparison websites and regulatory disclosure requirements may mean the information IS available but consumers choose not to seek it, in which case the failure is one of motivation (inertia) rather than information access. [Ev1 + Ev2: mechanism (information available but not sought) + "only if" condition (only if information genuinely unavailable) ✓]

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PARAGRAPH 3 — CONDITIONAL JUDGEMENT

On balance, inertia and status quo bias is the more fundamental cause of irrational non-switching because it operates even when information is fully available.. the 30% who cite effort as the barrier confirm they know switching is possible but do not act, whereas the 22% who cite information gaps represent a solvable problem that could be addressed by policy disclosure without any change in consumer psychology. [E1: Decision + E2: Justification — "solvable vs fundamental" is new reasoning not in body chains ✓]

The combined evidence — 52% of non-switching consumers explained by either effort or information gaps, representing more than half the non-switching population. — confirms the scale of irrational behaviour in this market is substantial and economically significant at the aggregate level, given that AUS$1,000 × millions of non-switching households represents a large total annual welfare loss. [E3: Extract anchor — combines 30% + 22% with AUS$1,000 in a new synthesis ✓]

This conclusion that inertia is the primary cause holds only if the psychological cost of switching is not reducible through structural intervention.. if comparison website design, automatic switching schemes, or annual renewal reminders can reduce the perceived effort cost of switching to near-zero, inertia may be nearly as solvable as information failure, in which case both causes are equally tractable and the distinction collapses. [E4: "only if" condition — structural intervention as named condition ✓]

However, if poor computational skills are the dominant mechanism — where consumers genuinely cannot evaluate which tariff generates the larger expected saving, rather than lacking motivation or information. — then neither comparison websites nor information disclosure fully addresses the root cause, and behavioural interventions (pre-calculated savings shown in absolute dollar terms, automatic switching to cheapest available tariff) represent the only reliable correction. In this case, the policy implication and the theoretical cause differ from both the inertia and information failure framings. [E5: Counter-condition (computational skills as third distinct cause) + new policy implication not in body ✓]

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#MARK AWARD AND JUSTIFICATION

KAA BAND:

KAA mark: 12/12 — Level 4 top

Examiner rationale: Both chains reach Stage 4. Extract data embedded at S2 on both chains (AUS$1,000, 30%, 22%). P2 evaluates Chain 1 before Chain 2 is presented.. bilateral development confirmed. Chain 2 S4 introduces the "does not know what they do not know" framing and policy implication — precise, on-question, multi-stage. No stages omitted on either chain. Level 4 confirmed.

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EVALUATION BAND:

Evaluation mark: 8/8 — Level 3 top

TOTAL: 20/20

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#THREE THINGS THIS ESSAY DOES THAT MOST DON'T

1 — P2 challenges Chain 1 with a specific mechanism. The "high-income rational non-switching" argument is not generic ("some people may act rationally"). It identifies which consumers, what makes their non-switching rational, and why this holds only for a narrow income band. This is what P2 looks like at Level 4 standard.

2 — S4 on Chain 2 is genuinely new. "Does not know what they do not know" with the policy implication (comparison websites address information but not inertia) is content that was not in Chain 1 and was not in S1–S3 of Chain 2. It extends the argument to welfare policy. Most students stop at S3 ("cannot make rational decision") and miss S4.

3 — E5 introduces a third cause. The conditional judgement's counter-condition (computational skills) is a third distinct mechanism not developed in either body chain. It reframes the policy question. This is the difference between a judgement that summarises the body (Level 3 entry, 7/8 eval) and one that adds genuine new synthesis (Level 3 top, 8/8 eval).

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#MARK COST TABLE

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#THE SEVEN CONFIRMED IRRATIONAL BEHAVIOUR REASONS (WEC11)

For this question type, Pearson confirms all seven of these as valid KAA content. Two fully developed = Level 4. Listing all seven without development = Level 2.

The Level 4 rule: Two of these seven, each developed to Stage 4, with extract data embedded. Not all seven listed at Stage 1–2.

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VERIDIAN WEC11 · CODEX SERIES · 20/20 EXEMPLAR — IRRATIONAL BEHAVIOUR