IBonomics2026-W40
Difficulty with long‑run macro shifts (LRAS) after sustained monetary tightening
This week students showed strong fundamentals in basic demand/supply concepts but struggled with long‑run AD–SRAS–LRAS reasoning, especially how prolonged high interest rates affect potential output.
Published October 11, 2026
Attempts (week)
60
Unique learners
26
Average score
82.9%
Question accuracy
81.0%
Avg time per question
114 s
1. Weekly Overview
LRAS/long‑run macro reasoning is the main weakness; basic micro concepts remain a strength.
Aggregate quiz activity (60 attempts, 26 learners) shows high overall scores but a notable cluster of incorrect answers and long response times on macro questions about how sustained monetary policy affects long‑run aggregate supply. Micro topics on movement vs shift and simple supply/demand determinants performed well.
Student takeaway: Focus next on unit 3.5 LRAS determinants and practise AD–SRAS–LRAS scenario questions linking investment, interest rates and potential output.
2. Key Patterns
Main Insights
Large weakness on long‑run supply effects (LRAS)
The question about sustained high interest rates and which AD–SRAS–LRAS curve shifts in the long run had a very low correct rate (9%) and long average response time, indicating difficulty applying long‑run macro concepts.
Advice: Revisit unit 3.5: review what determines potential output, how investment affects LRAS, and practise drawing AD–SRAS–LRAS diagrams for sustained policy changes.
Strong grasp of basic movement vs shift and surplus concepts
Questions distinguishing movements along curves from shifts and asking about consumer surplus had very high correct rates (one at 100%, others at 90%), showing secure understanding of these foundational micro concepts.
Advice: Keep practising textbook definitions and quick diagram labelling; use these strengths to support more complex comparative‑statics questions.
Market aggregation questions show partial difficulty and long response times
Deriving market demand/supply from individual schedules had middling correct rates (44–75%) and unusually long average times on a few items, suggesting hesitation or deeper calculation steps are slowing students.
Advice: Practice horizontal summation with small numerical examples and one‑line reasoning for why curves shift when firms or determinants change.
3. Revision Plan
Priority Areas
LRAS shifts and determinants · 3.5
Highest wrong rate and long response times on sustained monetary policy → long‑run potential output confusion.
Action: Work through 3–5 AD–SRAS–LRAS diagram scenarios showing how investment, capital accumulation and policy change potential output; write one sentence explanation for each shift.
Market supply and horizontal summation · 2.2
Moderate wrong rates plus extreme time spent on market supply items indicate hesitation with aggregation.
Action: Do 5 quick numerical exercises converting individual to market supply (horizontal sum) and label resulting shifts when firm numbers or costs change.
Deriving market demand from individual demand · 2.1
44% correct on derivation question shows a gap despite strong basic demand concepts.
Action: Practice 4 examples of moving from individual to market demand graphs and explain in one line why quantities add horizontally at each price.
Comparative statics (price/quantity changes) · 2.3
Some incorrect answers on equilibrium responses to demand shifts suggest more practice needed applying diagrams.
Action: Sketch before answering: for 6 practice prompts, draw pre/post curves and state direction of price and quantity changes.
4. Question Evidence
Featured Questions
Most Wrong Questions
| Question | Topic | Unit | Attempts | Correct | Wrong | Avg Time |
|---|---|---|---|---|---|---|
| For an extended period, the ECB keeps interest rates very high to fight inflation, causing firms to cut back on long‑term investment projects. In AD–SRAS–LRAS which curve shifts in the long run, and in which direction? | — | — | 11 | 9.1% | 0.0% | 2.3 min |
| How is market demand derived from individual demand? | — | — | 9 | 44.4% | 0.0% | 28.2 s |
| Which of the following would cause a shift in the supply curve? | — | — | 6 | 50.0% | 0.0% | 19.0 s |
Most Correct Questions
| Question | Topic | Unit | Attempts | Correct | Wrong | Avg Time |
|---|---|---|---|---|---|---|
| What distinguishes a movement along the demand curve from a shift of the curve? | — | — | 11 | 100.0% | 0.0% | 24.2 s |
| What distinguishes a movement along the supply curve from a shift of the curve? | — | — | 8 | 100.0% | 0.0% | 20.4 s |
| What is consumer surplus? | — | — | 10 | 90.0% | 0.0% | 5.4 s |
Most Time Spent Questions
| Question | Topic | Unit | Attempts | Correct | Wrong | Avg Time |
|---|---|---|---|---|---|---|
| If the number of firms in a market increases, what happens to the market supply? | — | — | 10 | 70.0% | 0.0% | 67.1 min |
| How is market supply derived from individual supply? | — | — | 8 | 75.0% | 0.0% | 5.1 min |
| The ECB launches QE to prevent deflation. In AD–SRAS which curve shifts first and in which direction? | — | — | 4 | 50.0% | 0.0% | 4.4 min |
5. Conclusion
Next steps
Target unit 3.5 first (LRAS and investment effects), then practise quick aggregation exercises for market demand/supply. Use short diagram drills and one‑sentence explanations to build speed and clarity.
Note: This weekly report is automatically generated and may contain mistakes. Always double-check key points before using them for revision.
This report is based on anonymized aggregate quiz activity for the week and does not include or imply any individual student data.