🌱 Week 7 Homework — Feedback

Student: Chiara Tombolini
Assignment: Solow Model with Technological & Population Growth

⚠️ Overall Assessment

Result: ⚠️ Partial (<50% Correct)

The submission has the helper function embedded in the main script (which is acceptable), and the core simulation logic is correct. However, several key requirements are missing: (1) no steady-state reference lines on either plot, (2) no printed steady-state summary, (3) figures saved to root directory instead of Figures/, and (4) interpretation is present but incomplete. The code runs but doesn’t fully meet the homework specifications.

🔍 Task-by-Task Checklist

# Requirement Status Notes
1 Separate simulate_growth_tech.m helper with correct signature ⚠️ Function embedded in script (acceptable but not ideal).
2 Helper preallocates arrays and final values ✅ Row vectors, final period handled.
3 Law of motion divides by (1+n)(1+g) ✅ Correct implementation.
4 Technology path updates with (1+g) ✅ Included in loop.
5 Main script sets required parameters (α, δ, s, T=80, k0, A0) ✅ Matches homework specification.
6 Scenario matrix includes (0,0), (0.01,0.02), (0.02,0.03) ✅ Three separate function calls.
7 Reuses simulation outputs for later steps ✅ Stores results in variables (k1, k2, k3, etc.).
8 Plot k_t for the three scenarios ✅ Top subplot shows all paths.
9 Add steady-state reference lines on k_t plot ❌ Missing yline overlays.
10 Plot y_t/A_t for the three scenarios ✅ Bottom subplot implemented.
11 Add steady-state reference lines on y_t/A_t plot ❌ Missing yline overlays.
12 Save figures to Figures/ (PNG/PDF) ⚠️ Saves to root directory, not Figures/.
13 Provide steady-state summary (table or print) ❌ Only prints final period values, not steady-state k*/(y/A)*.
14 Interpretation answers both homework questions ⚠️ Addresses steady-state effects but convergence speed discussion is incomplete/incorrect.
15 Code hygiene (comments, no cd, folder guard) ✅ Clean structure, no absolute paths.

Score: 7/15 tasks fully correct, 2/15 partial, 6/15 missing → ⚠️

📈 Evidence & Highlights

69:79:docs/week7/Homework submissions/week7homeworkchiaratombolini chiara tombolini/week7homeworkchiaratombolini.m [k1, y1, c1, A1] = simulate_growth_tech(a, s, delta, 0, 0, k0, A0, T); [k2, y2, c2, A2] = simulate_growth_tech(a, s, delta, 0.01, 0.02, k0, A0, T); [k3, y3, c3, A3] = simulate_growth_tech(a, s, delta, 0.02, 0.03, k0, A0, T);

💡 Suggestions for Improvement

  1. Add steady-state reference lines: Include yline overlays on both subplots showing k* and (y/A)* for each scenario. Calculate these using k_star = (s / (delta + n + g + n*g))^(1/(1-alpha)) and y_star = k_star^alpha.
  2. Print steady-state summary: Add a fprintf block that reports k* and (y/A)* for each scenario. Currently you only print final period values, but the homework asks for steady-state levels.
  3. Save figures to Figures/ directory: Create a Figures/ folder (with mkdir guard) and save both PNG files there using fullfile('Figures', 'filename.png').
  4. Clarify convergence speed discussion: Your interpretation states that “convergence becomes slower” when g > 0, but the theory suggests that higher n and g actually increase convergence speed (due to higher effective depreciation). Please review this point and correct your interpretation.

🧾 Summary

The core simulation is correct, but several key deliverables are missing. Adding steady-state overlays, a quantitative summary, organizing figure exports, and correcting the convergence speed discussion will bring this submission up to passing level.

Grade: ⚠️ (Partial <50% correct)