equalizing_difference#

  • Series: lecture-python-intro

  • File: lectures/equalizing_difference.md

  • Audit date: 2026-08-26

  • Corpus snapshot: a12d17c0ef

  • Categories audited: writing, math, code, figures, references, links, admonitions (JAX out of scope)

  • Overall score: 7.9 / 10

  • Priority: LOW

Score breakdown#

Category

Score

One-line note

Writing

5/10

qe-writing-002 ×5; qe-writing-005 ×2; qe-writing-008 ×42, +1 more.

Math

8/10

qe-math-001 ×2.

Code

7.5/10

qe-code-001 ×5.

JAX

out of scope

JAX rules target lecture-jax.

Figures

5.5/10

qe-fig-006 ×5; qe-fig-005 ×7; qe-fig-008 ×8.

References

9/10

qe-ref-001 ×1.

Links

10/10

no mechanical violations detected.

Admonitions

10/10

no mechanical violations detected.

Issues#

Critical#

None found.

High severity#

  • [qe-code-001] (reviewer) — Follow PEP8 unless closer to mathematical notation. Count: 5. Lines: 190, 316, 565, 569, 611. Example: the closing ): of create_edm at 190 and of create_edm_π at 316 is indented three columns short of the visually-aligned arguments above it; the exercise solutions pad assignments and arguments to align them - gaps_free   = [...] / gaps_costly = [...] at 565-566, ax.plot(T_arr, gaps_free,   'o-', ...) at 569-570, gap_plus  = ... / dϕ_dR_fd  = ... at 611-613 - which PEP8 rules out (multiple spaces before an operator, multiple spaces after a comma) and which the body of the lecture does not do.

  • [qe-fig-005] — Descriptive figure names for cross-referencing. Count: 7. Lines: 233, 249, 268, 345, 512, 562, 648. Example: code-cell figure without mystnb figure metadata.

  • [qe-fig-006] — Lowercase axis labels. Count: 5. Lines: 522, 572, 573, 656, 657. Example: axis label College wage premium $\phi$.

  • [qe-fig-008] — Use lw=2 for line charts. Count: 8. Lines: 238, 254, 273, 350, 519, 569, 570, 654. Example: plot() without lw=.

  • [qe-writing-002] (reviewer) — Keep writing clear, concise, and valuable. Count: 5. Lines: 22, 34, 44, 178, 368. Example: line 22 is a 38-word sentence carrying Friedman’s motive, the dentists/doctors comparison and the entry-barrier alternative at once; line 34 runs 31 words and ends with the redundant “between going to college and not going to college but instead going to work immediately”; line 44 “And doing that will let illustrate how good Python is at doing calculus!” is ungrammatical; line 178 restates line 170 almost verbatim across the section break (“write Python code to compute \(\phi\) and plot it as a function of … its determinants”); and 362-372 spends five sentences re-announcing the calculus section that lines 42-46 already announced in the Overview.

  • [qe-writing-008] — Remove excessive whitespace between words. Count: 42. Lines: 22, 25, 27, 30, 32, 34, 38, 42, 69, 75, …. Example: 3 spaces.

Medium severity#

  • [qe-math-001] — Prefer UTF-8 unicode for simple parameter mentions, be consistent. Count: 2. Lines: 447, 462. Example: unicode γ inside a math environment.

  • [qe-writing-005] (reviewer) — Use bold for definitions, italic for emphasis. Count: 2. Lines: 38, 244. Example: bold used where italic is called for: Wealth of Nations at 38 is a book title, and waiting at 244 is emphasis (“must rise to compensate a prospective high school student for waiting to start receiving income”) - neither is a definition, while the genuine definitions equalizing difference (130) and free college (160) use the same weight.

Low severity#

  • [qe-ref-001] — Use correct citation style. Count: 1. Lines: 25. Example: {cite} in narrative flow: ‘of {cite}’.

  • [qe-writing-003] (reviewer) — Maintain logical flow. Count: 1. Lines: 428. Example: “Thus, as with our earlier graph, we find that raising \(R\) increases the initial college wage premium \(\phi\)” sits directly under the cells at 417-425, which compute and evaluate \(\partial\phi/\partial D\), not \(\partial\phi/\partial R\) - the \(R\) derivative is not computed until 480 and is correctly discussed at 490, so the reader meets the conclusion 60 lines before its evidence.

Strengths#

  • The model is packaged once as a namedtuple plus a create_edm factory with the economics written into the default comments (181-192), so every comparative-statics cell reduces to one list comprehension over create_edm(...) (235, 251, 270, 347) instead of re-deriving \(A_h\) and \(A_c\).

  • Greek parameters in code are Unicode and match the mathematics symbol for symbol - γ_h, γ_c, ϕ, π, ε, w_h0 - so a reader can move between the display equations and the cells without a translation table.

  • Every comparative static is established twice: graphically at 233-277 and again symbolically with SymPy at 376-490, and each derivative’s sign is checked back against the corresponding graph (460, 475, 490).

  • The entrepreneur-worker reinterpretation at 279-356 reuses the same indifference equation with a single extra parameter \(\pi\), which makes the model’s real subject - waiting and risk, not college - visible without new algebra.

  • All four exercises are gated {exercise} / {solution-start} … {solution-end} with :class: dropdown, and three of them close the loop numerically against the lecture’s own symbolic results (531-535, 616-620, 663-667).