Original collectionUnder development

Under development — library extension. This report is part of the expanded-library work, not the original collection. Source preparation, methods and results are subject to revision.

Provisional eligibility assessment — under development. TreatImp and TreatExp are continuous import/export tariff-reduction exposures interacted with the NAFTA period. The design is continuous-treatment DiD, outside this binary-treatment template rather than invalid DiD. This working assessment is not fully vetted and may change. See the report below for its recorded replication or assessment status. Provisional eligibility log

Free Trade and the Formation of Environmental Policy: Evidence from US Legislative Votes

Jevan Cherniwchan; Nouri Najjar (2025). American Economic Journal: Economic Policy.

Under development — community extension. This is a provisional source-design assessment, not a new successful replication or a final eligibility ruling.

Extension index · Provisional eligibility log · Assessment JSON · QMD · Reproduction code

Source design and template applicability

TreatImp and TreatExp are continuous import/export tariff-reduction exposures interacted with the NAFTA period. The design is continuous-treatment DiD, outside this binary-treatment template rather than invalid DiD.

No DiD estimates, uncertainty intervals or homogeneity-test decision were computed in this tranche. No point is added to the calibration plots. This is not a zero effect or a failed statistical test.

Recorded treatment-column measurement

405 distinct nonmissing values in TreatImp.

Observed support in the indicated source frame; missing values excluded. N=52,312; missing=0. Frame: selected_source_data. Source: /Volumes/LAL_BAK/did-cardinality-work/packages/Cherniwchan_Najjar_AEJ-Policy_2025_201822/processed/analysis/nafta_house_1990_2001_clean.dta.

These are the existing data-measured counts, not counts inferred from design labels. A binary instrument, group indicator or interaction component need not be the treatment of interest; the source-design assessment above takes precedence for template applicability.

Replication status

This tranche: unsupported design; source code/documentation inspected, no estimator run.

Supplied library: verified; verification: verified; preparation: runs_with_shim. These are the library’s labels, not new verification claims. Missing data and unsupported designs are separate issues.

Evidence and provenance

The following files in the supplied library were inspected. Their SHA-256 digests are recorded in the downloadable assessment JSON. Source archives and microdata are not redistributed.

• AEJ-Policy/Cherniwchan_Najjar_AEJ-Policy_2025_201822/R/128_cherniwchan_najjar_figure.R (84 lines)
• AEJ-Policy/Cherniwchan_Najjar_AEJ-Policy_2025_201822/R/128_cherniwchan_najjar_replicate.R (271 lines)
• AEJ-Policy/Cherniwchan_Najjar_AEJ-Policy_2025_201822/verdict.md (71 lines)
• AEJ-Policy/Cherniwchan_Najjar_AEJ-Policy_2025_201822/aeraej-128.md (240 lines)