Add short aliases for all estimators

[igerber]

Summary

• Add 12 convenience aliases (DiD, TWFE, EventStudy, SDiD, CS, CDiD, SA, BJS, Gardner, DDD, Stacked, Bacon) for verbose estimator class names
• Add aliases to __all__ for discoverability
• Add tests verifying alias identity, __all__ membership, and instantiation
• Document aliases in API reference and quickstart guide

Methodology references (required if estimator / math changes)

• N/A — no methodology changes, only name aliases in __init__.py

Validation

• Tests added: tests/test_aliases.py (3 tests: identity, __all__, instantiation)
• All tests pass: pytest tests/test_aliases.py -v

Security / privacy

• Confirm no secrets/PII in this PR: Yes

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Generated with Claude Code

[github-actions]

Overall assessment: ⚠️ Needs changes

Executive Summary

• Alias exports/tests/docs are the only changes; no estimator math/SE/assumption logic is touched.
• Registry cross-check shows a doc/coverage mismatch: TROP is an estimator in the registry but is not covered by the “all estimators” alias claim.
• No other code quality, performance, or security issues observed in this diff.

Methodology

• P2 — Impact: Docs state “short aliases are available for all estimators,” but the Methodology Registry lists TROP as an estimator and there is no short alias defined/exported for it; this makes the claim inaccurate and can mislead users who expect a missing alias. Concrete fix: either add a short alias for TROP (and include it in alias tests), or reword the docs to “selected estimators” and note that TROP already uses its short canonical name. References: docs/api/estimators.rst:20, diff_diff/__init__.py:162, diff_diff/__init__.py:189, docs/methodology/REGISTRY.md:1019, tests/test_aliases.py:24.

Code Quality
No findings.

Performance
No findings.

Maintainability
No findings.

Tech Debt
No findings.

Security
No findings.

Documentation/Tests
No additional findings. Tests not run in this review.

[igerber]

/ai-review

[github-actions]

🔁 AI review rerun (requested by @igerber)

Head SHA: 36f2d7530b46f23476875a90a310b1bcf6ee085b

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Overall assessment: ✅ Looks good

Executive Summary

• Alias-only changes in diff_diff/__init__.py:162 do not touch estimator logic, weighting, inference, or defaults; Methodology Registry adherence is unchanged.
• Added tests cover alias identity and __all__ membership, with a basic instantiation check. tests/test_aliases.py:1
• Minor documentation categorization issue: Bacon Decomposition is a diagnostic in the Methodology Registry but is presented as an estimator alias in docs/comments, which can mislead users. docs/api/estimators.rst:20, diff_diff/__init__.py:162, docs/methodology/REGISTRY.md:22

Methodology

• No findings. Alias definitions only; no estimator math or assumptions changed. diff_diff/__init__.py:162

Code Quality

• No findings.

Performance

• No findings.

Maintainability

• No findings.

Tech Debt

• No findings.

Security

• No findings.

Documentation/Tests

• Severity: P3. Impact: Bacon Decomposition is categorized under Diagnostics & Sensitivity in the Methodology Registry but is described alongside estimator aliases, which can cause user confusion about its role. Fix: adjust wording to “estimators and diagnostics” or move Bacon to a diagnostics alias list; optionally update the “Estimator aliases” comment. docs/api/estimators.rst:20, diff_diff/__init__.py:162, docs/methodology/REGISTRY.md:22
• No findings. Tests not run in this review.