2026-W21
Students struggle with simultaneous shifts and supply-response reasoning
This week’s quizzes show strong grasp of basic shift rules but clear confusion when multiple shocks interact or when cost shocks are mistaken for demand changes.
Published May 31, 2026
Total quiz attempts
311
Active students (unique)
35
Average score
83.3%
Overall question accuracy
80.8%
Average time per question
41.8s
1. Weekly Overview
Good basics; difficulties with multi-shock diagrams and supply causation
Aggregate results (311 attempts, 35 learners) show high accuracy on single-shift items (taxes, subsidies, complements/substitutes) but large error rates on questions that require drawing or interpreting simultaneous shifts and separating cost shocks from demand shifts.
Student takeaway: Prioritise diagram practice on simultaneous demand/supply shifts and on identifying whether a price change is driven by demand or cost-side supply factors.
2. Key Patterns
Main Insights
Largest weakness — interpreting simultaneous shifts
Two high-attempt items (unit 2.1 and 2.2) had very low correct rates (~13.6%): learners often mis-predict prices/quantities when demand and supply are affected at the same time (e.g., subsidy + expectation shocks).
Advice: When two curves move, draw both shifts, label direction for quantity and price, and then compare effects on price and quantity separately — practice with simple magnitude reasoning (which shift is likely larger?).
Confusion between cost shocks and demand changes
A sizable subset of learners misattributed price rises from higher input costs to increases in supply; interpretations of supply shifts driven by input costs remain weak.
Advice: Practice identifying the cause: if an input becomes more expensive, shift supply left (higher price, lower quantity); demand remains unchanged unless buyer preferences or incomes change.
Strength — clear knowledge of single-shift rules and complements/substitutes
Several easy items scored near-perfectly (e.g., effects of subsidies, indirect taxes, complements/substitutes), indicating reliable recall of basic diagram rules and textbook comparative statics.
Advice: Keep using timed single-shift practice to keep these fundamentals fast and automatic, then layer complexity (second shift) once single shifts are secure.
3. Revision Plan
Priority Areas
Simultaneous shifts (demand & supply) · 2.2
Highest evidence of error on multi-shock diagram questions with many attempts and very low correct rates.
Action: Practice 6–8 diagram questions that combine two shocks; on each, write separate short notes: (1) which curves shift, (2) short-run effect on price, (3) short-run effect on quantity, and (4) where the answer is ambiguous without magnitudes.
Cost shocks vs demand changes · 2.2
Frequent mistakes attributing price rises to supply increases instead of cost-driven supply decreases.
Action: Work through examples where input costs change (e.g., cocoa, fuel) and explain aloud or in writing why supply shifts left/right while demand stays constant.
Equilibrium adjustments and comparative statics · 2.1
Some learners expect firms to 'instantly' increase supply in response to higher demand without considering short-run constraints.
Action: Do timed practice drawing short-run supply curves and annotate which adjustments require time (capacity, production) vs immediate price effects.
AD–SRAS short-run responses to fiscal/wage shocks · 3.2 / 3.6
Low correct rates and long response times on macro questions about wage-led inflation and currency appreciation effects.
Action: Review AD/AS diagrams: practice 4 scenarios (fiscal expansion, wage shock, currency appreciation, demand shock) and state the short-run curve movement and expected price/output effect.
4. Question Evidence
Featured Questions
Most Wrong Questions
| Question | Topic | Unit | Attempts | Correct | Wrong | Avg Time |
|---|---|---|---|---|---|---|
| A student says: “When demand for concert tickets increases, firms will increase their supply, so prices will fall back down.” Using a demand and supply diagram, what actually happens when demand for concert tickets rises? | Microeconomics | 2.1 | 44 | 13.6% | 86.4% | 19.7 s |
| In a single diagram for solar panels, show the effects of a government production subsidy and rising expectations that future electricity prices will be much higher. | Microeconomics | 2.2 | 44 | 13.6% | 86.4% | 29.8 s |
| A student says, 'Because the price of chocolate bars has risen, supply must have increased,' but the price rise was caused by higher cocoa costs. What happens to demand and supply? | Microeconomics | 2.2 | 34 | 50.0% | 50.0% | 44.5 s |
| What happens if the domestic currency appreciates significantly, making imports cheaper and exports more expensive to foreigners? | Macroeconomics | 3.2 | 26 | 42.3% | 57.7% | 34.9 s |
| How is the economy affected when nominal wages rise significantly across the economy due to strong trade union bargaining? | Macroeconomics | 3.2 | 18 | 27.8% | 72.2% | 1.1 min |
Most Correct Questions
| Question | Topic | Unit | Attempts | Correct | Wrong | Avg Time |
|---|---|---|---|---|---|---|
| If the price of sugar increases, what happens to the demand for tea, a complementary good? | Microeconomics | 2.1 | 50 | 100.0% | 0.0% | 9.3 s |
| What happens to the demand curve when consumer income increases? | Microeconomics | 2.1 | 50 | 100.0% | 0.0% | 48.3 s |
| What are the effects on demand and supply from a government subsidy? | Microeconomics | 2.2 | 47 | 100.0% | 0.0% | 14.4 s |
| The government introduces a higher indirect tax on sugary drinks. What happens to the market supply of sugary drinks? | Microeconomics | 2.2 | 42 | 100.0% | 0.0% | 10.8 s |
| Laptops and tablets are substitutes, while laptops and laptop cases are complements. A large fall in the price of tablets occurs at the same time as a small fall in the price of laptop cases. If the substitution effect from tablets is stronger than the complement effect from cheaper laptop cases, what happens to the demand for laptops? | Microeconomics | 2.1 | 43 | 97.7% | 2.3% | 31.4 s |
Most Time Spent Questions
| Question | Topic | Unit | Attempts | Correct | Wrong | Avg Time |
|---|---|---|---|---|---|---|
| What does unitary price elastic supply mean? | microeconomics | 2.6 | 4 | 100.0% | 0.0% | 96.2 min |
| A key production technology used in producing electric cars becomes obsolete and must be replaced with more expensive equipment. What happens to the market supply of electric cars in the short run? | Microeconomics | 2.2 | 11 | 100.0% | 0.0% | 19.4 min |
| Consider game consoles (e.g., PS5) and high-end gaming PCs as substitutes, and PS5 consoles and PS5 games as complements. The price of gaming PCs rises significantly, while the average price of PS5 games falls slightly. Assuming both effects work in the same direction, what happens to the demand for PS5 consoles? | Microeconomics | 2.1 | 10 | 100.0% | 0.0% | 11.9 min |
| Ibonomica enters a deep recession with high cyclical unemployment. The government responds by increasing spending on infrastructure and cutting income taxes. In a standard AD–SRAS diagram, which curve is most likely to shift in the short run, and in which direction? | Macroeconomics | 3.6 | 22 | 100.0% | 0.0% | 10.1 min |
| Which indicator is most likely to include measures of life satisfaction, housing, and education? | Macroeconomics | 3.1 | 5 | 80.0% | 20.0% | 7.4 min |
5. Conclusion
Next steps for the week
Keep practising single-shift diagrams to maintain strengths, then focus short sessions on paired-shift problems and cost-versus-demand scenarios; write one-line explanations for each diagram to make reasoning explicit.
Note: This weekly report is automatically generated and may contain mistakes. Always double-check key points before using them for revision.
This report summarises anonymized aggregate quiz activity from the indicated week; no individual learner data is shown.