IBonomics2026-W35
Diagrams: multi-effect shifts are the weakest area this week
Aggregate results show strong performance on single-effect AD questions but clear weaknesses when multiple forces must be shown in one diagram.
Published September 6, 2026
Total attempts
131
Average score
83%
Question accuracy
80.0%
Unique students
35
Longest avg question time
≈55.6 min (outlier)
1. Weekly Overview
Students handle single-effect AD shifts well but struggle with multi-factor diagram questions.
Average score across the week was 83% with particularly high accuracy on straightforward AD questions. The lowest scores occurred on tasks requiring combined shifts or multiple diagrams (micro supply/demand with expectations and macro three-curve shifts). Time-on-question varied widely, with some definition items showing unusually long times.
Student takeaway: Prioritise practice on combined diagram problems (Unit 2.2) and three-curve AD/SRAS/LRAS reasoning (Unit 3.2).
2. Key Patterns
Main Insights
Biggest weakness — multi-effect diagram questions (Micro, Unit 2.2)
Items asking students to show multiple simultaneous effects in a single supply/demand diagram had very low correct rates (one key item 0% correct; others ~33–43%). These problems also sometimes took longer than average, suggesting hesitation or stepwise errors.
Advice: When drawing combined shifts, write the sequence of effects first (what changes demand, what changes supply), label each shift clearly, and redraw the final equilibrium. Practice with 2-effect scenarios (e.g., subsidy + rising expectations) until you can explain each shift in one sentence before drawing.
Macro three-curve questions show confusion about which curve shifts
Several AD/SRAS/LRAS items had low correct rates (~25–31%); students correctly answer many single-effect AD items but struggle when asked which of AD, SRAS or LRAS moves for longer-term capacity changes versus short-run price changes.
Advice: Use the rule: AD moves with demand/policy changes; SRAS moves with short-run costs and supply shocks; LRAS moves only with changes to productive capacity (labour, capital, technology). Practice classifying shocks first, then place shifts on the three-curve diagram.
Strength — clear understanding of standard AD effects
Students performed strongly on single-effect AD questions (several items 95–100% correct), indicating reliable grasp of how taxes, confidence and public spending affect AD.
Advice: Keep practising single-effect AD scenarios to maintain speed, then build up to combined scenarios by adding one extra factor at a time.
Time-outliers on short definition items — interpret cautiously
A few definition/definition-style items show extremely long average times (minutes to tens of minutes). These are likely outliers from small attempt counts, possibly reflecting interruptions or careful reading rather than difficulty.
Advice: If you find yourself spending several minutes on a definition, pause and check the exact wording; practise concise definitions under timed conditions.
3. Revision Plan
Priority Areas
Combined supply & demand shifts (two-factor diagrams) · 2.2
Lowest correct rates concentrated on multi-effect micro diagram questions.
Action: Practice 10 mixed-shock problems: identify each shock first, state direction for supply and demand, then draw final diagram and explain equilibrium changes in one sentence.
Three-curve AD/SRAS/LRAS reasoning · 3.2
Many errors about which curve shifts for long-run capacity versus short-run shocks.
Action: Create a 2-column cheat sheet (short-run vs long-run causes) and run 8 practice questions distinguishing AD, SRAS and LRAS shifts.
Policy plus expectation combinations · 2.2
Items combining policy (subsidy/tax) with expectations produced mixed answers and longer times.
Action: Work through 6 examples where a policy and a demand/supply expectation change at once; label sequence and check income/price effects.
Timed definition recall · 2.9
Some definition items show long times despite correct answers — practice under time to avoid time-risk in exams.
Action: Do 20 timed flashcards (60s max each) for key definitions and stakeholder roles.
4. Question Evidence
Featured Questions
Most Wrong Questions
| Question | Topic | Unit | Attempts | Correct | Wrong | Avg Time |
|---|---|---|---|---|---|---|
| If AI chip producers expect much higher prices for AI chips next year and ramp up production now, what happens to the current market supply of AI chips? | Microeconomics | 2.2 | 21 | 33.3% | 66.7% | 1.6 min |
| In a single diagram for electric cars, show the impact of falling battery costs and rising incomes that make more households able to afford EVs. | Microeconomics | 2.2 | 11 | 0.0% | 100.0% | 35.3 s |
| Due to an AI takeover that ends in all technology being wiped out, many firms end up operating with outdated machinery and inefficient production methods. In the three-curve diagram, which curve is most directly influenced and in which direction does it shift? | Macroeconomics | 3.2 | 12 | 25.0% | 75.0% | 29.8 s |
| A government launches a long-term infrastructure plan, building new highways, ports and digital networks that permanently expand the economy’s productive capacity. In the standard macroeconomic diagram with AD, SRAS and LRAS, which curve is most likely to shift and in which direction? | Macroeconomics | 3.2 | 13 | 30.8% | 69.2% | 25.5 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 | 14 | 42.9% | 57.1% | 1.4 min |
Most Correct Questions
| Question | Topic | Unit | Attempts | Correct | Wrong | Avg Time |
|---|---|---|---|---|---|---|
| How is the long-run aggregate supply curve affected if a country experiences a sustained increase in net immigration of skilled workers, expanding the available labour force? | Macroeconomics | 3.2 | 27 | 85.2% | 14.8% | 1.1 min |
| How is aggregate demand affected when households become more confident about the future and expect their incomes to rise? | Macroeconomics | 3.2 | 21 | 100.0% | 0.0% | 16.2 s |
| What happens to aggregate demand if the government raises income taxes on households, reducing their disposable income? | Macroeconomics | 3.2 | 22 | 95.5% | 4.5% | 14.9 s |
| If the government implements austerity measures and cuts public spending on welfare benefits and public sector wages, what happens to aggregate demand in the short run? | Macroeconomics | 3.2 | 20 | 100.0% | 0.0% | 14.6 s |
| How is the economy impacted when there is a significant improvement in worker productivity due to automation? | Macroeconomics | 3.2 | 17 | 100.0% | 0.0% | 10.2 s |
Most Time Spent Questions
| Question | Topic | Unit | Attempts | Correct | Wrong | Avg Time |
|---|---|---|---|---|---|---|
| What does competitive supply mean in economics? | microeconomics | 2.2 | 4 | 100.0% | 0.0% | 55.6 min |
| What problem arises when people can consume a good without paying for it? | Microeconomics | 2.9 | 7 | 71.4% | 28.6% | 20.7 min |
| Who are the main stakeholders affected by government intervention in markets? | Microeconomics | 2.7 | 8 | 75.0% | 25.0% | 15.6 min |
| What is the intended purpose of a price ceiling? | Microeconomics | 2.7 | 9 | 88.9% | 11.1% | 9.4 min |
| Which characteristic defines a common pool resource? | Microeconomics | 2.8 | 9 | 88.9% | 11.1% | 6.1 min |
5. Conclusion
Focus practice on combined diagrams
Start with single-effect diagrams to maintain speed, then add one extra effect and practise the sequence (identify cause → label curve → redraw equilibrium). Short, focused diagram drills in Units 2.2 and 3.2 will give the most immediate improvement.
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 for the week; no individual student data is shown.