dev-status.md

Development Status & Monitoring

Current-state notes, monitoring, and platform quirks — not a backlog. Shippable work lives in TODO.md; blocked / parked work and decisions on the record in DEFERRED.md. This file is repo-internal (excluded from the RTD build).

Large Module Files

Target: ideally < 1000 lines per module; modules ≥3000 lines are candidates for splitting, 2000-3000 are monitored, 1000-2000 are accepted as a cohesion / scope trade-off. Updated 2026-07-19.

File	Lines	Action
chaisemartin_dhaultfoeuille.py	8812	Consider splitting (per-path / placebos / survey IF / aggregation)
linalg.py	5424	Consider splitting (vcov surfaces) only if cohesion preserved — unified backend; vcov / solver paths tightly coupled
staggered.py	4992	Consider splitting — grew through survey + aggregation features
had.py	4748	Consider splitting (continuous / mass-point / event-study / survey paths)
had_pretests.py	4664	Consider splitting (Stute / Yatchew / QUG / joint pretests)
diagnostic_report.py	4135	Consider splitting (per-method renderers + provenance)
spillover.py	3655	Consider splitting
two_stage.py	3512	Consider splitting
power.py	3488	Consider splitting (power analysis + MDE + sample size)
utils.py	3483	Consider splitting
synthetic_control_results.py	3294	Consider splitting
honest_did.py	3068	Consider splitting
imputation.py	2898	Monitor
synthetic_did.py	2826	Monitor — variance methods + survey paths
business_report.py	2728	Monitor — per-method narrative renderers
survey.py	2681	Monitor — grew with Phase 6 features
synthetic_control.py	2526	Monitor
prep_dgp.py	2524	Monitor
estimators.py	2441	Monitor
continuous_did.py	2431	Monitor
sun_abraham.py	2314	Monitor
triple_diff.py	2231	Monitor
wooldridge.py	2192	Monitor
practitioner.py	2113	Monitor — grew with per-estimator handlers (was 1511 on 2026-07-13)
efficient_did.py	2083	Monitor
chaisemartin_dhaultfoeuille_results.py	2004	Monitor
results.py	1948	Acceptable
_rdrobust_port.py	1913	Acceptable
pretrends.py	1879	Acceptable
prep.py	1878	Acceptable
efficient_did_covariates.py	1818	Acceptable
staggered_triple_diff.py	1680	Acceptable
trop_local.py	1662	Acceptable
lpdid.py	1607	Acceptable
stacked_did.py	1589	Acceptable
changes_in_changes.py	1429	Acceptable
_nprobust_port.py	1425	Acceptable
bacon.py	1376	Acceptable
local_linear.py	1325	Acceptable
trop_global.py	1298	Acceptable
datasets.py	1224	Acceptable
rdd.py	1218	Acceptable
staggered_aggregation.py	1204	Acceptable
chaisemartin_dhaultfoeuille_bootstrap.py	1175	Acceptable
conley.py	1140	Acceptable
rdplot.py	1135	Acceptable
trop.py	1026	Acceptable
profile.py	1001	Acceptable

Standard Error Consistency

vcov_type has subsumed the previously-proposed se_type knob. DifferenceInDifferences and TwoWayFixedEffects accept vcov_type ∈ {classical, hc1, hc2, hc2_bm, conley} (the validated set in linalg.py::_VALID_VCOV_TYPES); cluster-robust variance comes from cluster= alongside the heteroscedasticity kind (hc1+cluster ⇒ CR1 Liang-Zeger; hc2_bm+cluster ⇒ CR2 Bell-McCaffrey, including the weighted WLS-CR2 port; the N>1 absorbed-FE + weights composition is supported via iterative alternating-projection demeaning, #586); wild cluster bootstrap is the separate inference="wild_bootstrap" path. Threading vcov_type through the 8 standalone estimators is complete (Phase 1b); four (CallawaySantAnna, TripleDifference, ImputationDiD, EfficientDiD) are permanently narrow to {hc1} per their influence-function variance, and TwoStageDiD is likewise narrow (Gardner GMM meat has no single cross-stage hat matrix). The per-estimator vcov_type="conley" extensions: SunAbraham + WooldridgeDiD-OLS are shipped; the IF/GMM estimators are tracked in DEFERRED.md → Paper-gated.

Type Annotations

mypy diff_diff is enforced at zero errors by the Lint CI workflow's Mypy job at the pinned mypy==2.3.0 (ungated, every PR push; pins synced with the dev extra via TestLintWorkflowPinSync). [tool.mypy] python_version targets "3.10" (mypy >= 2.2 cannot target 3.9); the Python 3.9 library floor is covered by a dedicated runtime leg in the gated test matrix instead. Zero is reached with documented suppressions — tightening them is tracked in TODO.md → Testing / docs:

• Global disable_error_code = ["arg-type", "return-value", "var-annotated", "assignment"] (numpy-stub compatibility, long-standing).
• Per-module override: diff_diff.prep_dgp disables [index] (seeded-DGP Optional covariate arrays; see the comment in pyproject.toml).
• matplotlib.* / plotly.* use follow_imports = "skip" so local and CI runs see identical Any surfaces regardless of what plotting stubs are installed.
• A handful of reasoned inline # type: ignore[code] comments, each with a why-comment; warn_unused_ignores = true prevents them from going stale.

Mixin cross-class attribute access uses TYPE_CHECKING-guarded attribute/method stubs in the bootstrap mixin classes; keep stubs in sync with implementations (stub drift shows up as [misc] unpack-arity errors).

Test Coverage

Visualization tests skip when matplotlib / plotly are not installed (see pytest.importorskip markers in tests/test_visualization*.py).

RuntimeWarnings — Apple Silicon M4 BLAS bug (numpy < 2.3)

Spurious RuntimeWarnings ("divide by zero", "overflow", "invalid value") are emitted by np.matmul/@ on Apple Silicon M4 + macOS Sequoia with numpy < 2.3, for matrices with ≥260 rows. They do not affect correctness (coefficients/fitted values are valid, designs full rank). Root cause: Apple's BLAS SME kernels corrupt the FP status register (numpy#28687, #29820; fixed in numpy ≥ 2.3 via PR #29223). Not reproducible on M3, Intel, or Linux.

• linalg.py:162 — warnings in fitted-value computation (X @ coefficients); seen in test_prep.py during treatment-effect recovery (n > 260).
• triple_diff.py:307,323 — warnings in propensity-score computation (IPW/DR with covariates); logistic-regression overflow in edge cases (separate from the BLAS bug).
• Long-term: revert to the @ operator when numpy ≥ 2.3 becomes the minimum supported version.