🌱 Week 7 Homework — Feedback

Student: Pablo Romanella
Assignment: Solow Model with Technological & Population Growth

✅ Overall Assessment

Result: ✅ More than 50% Correct

Good submission with correct helper function and proper parameter calibration. The code runs cleanly and produces clear subplot figures saved to the correct directory. The main gaps are: (1) missing steady-state reference lines on both plots, (2) no printed steady-state summary, and (3) interpretation is present but could be more explicit about convergence speed. The economic discussion addresses steady-state effects but doesn’t clearly answer the convergence speed question.

🔍 Task-by-Task Checklist

#	Requirement	Status	Notes
1	Separate `simulate_growth_tech.m` helper with correct signature	✅	Provided with four outputs.
2	Helper preallocates arrays and final values	✅	Column 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)`	✅	Stored in `n_and_g`.
7	Reuses simulation outputs for later steps	⚠️	Re-runs function for plotting.
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)	✅	Saved to `Figures_week7/` as PNG and `.fig`.
13	Provide steady-state summary (table or print)	❌	No numerical output of `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, `mkdir` guard included.

Score: 9/15 tasks fully correct, 1/15 partial, 5/15 missing → ✅

📈 Evidence & Highlights

23:32:docs/week7/Homework submissions/week7_Romanella Pablo ROMANELLA/Romanella_week7_homework.m subplot(2,1,1) plot(1:T, k, 'LineWidth', 1.5); hold on ... subplot(2,1,2) plot(1:T, y./A, 'LineWidth', 1.5); hold on

💡 Suggestions for Improvement

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.
Print steady-state summary: Add a fprintf block that reports k* and (y/A)* for each scenario. This will provide quantitative backing for your interpretation.
Clarify convergence speed discussion: Your interpretation states that “the economy converges to a steady state at a faster rate” when g > 0, but doesn’t explain why. Please elaborate on the mechanism (higher effective depreciation creates a stronger restoring force). Also, note that higher n and g both increase convergence speed, not just g.

🧾 Summary

Solid implementation with correct economics. Adding steady-state overlays, a quantitative summary, and clarifying the convergence speed discussion will complete the submission.

Grade: ✅ (More than 50% correct)