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title: "Pre-Event Trends in the Panel Event-Study Design"
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[Simon Freyaldenhoven; Christian Hansen; Jesse M. Shapiro (2019)](https://doi.org/10.1257/aer.20180609). *American Economic Review*.

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

[Extension index](development.html) · [Provisional eligibility log](development.html#eligibility-log) · [Assessment JSON](aeraej-154.json) · [QMD](aeraej-154.qmd) · [Reproduction code](collection-code.zip)

## Source design and template applicability

The source x_0 is the change in the number of daily newspapers, not a binary entry event. The turnout equation is a count-exposure panel event-study target; thresholding changes its estimand.

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

**14 distinct nonmissing values** in `x_0`.

Observed support in the indicated source frame; missing values excluded. N=15,627; missing=0. Frame: selected_source_data. Source: AER/Freyaldenhoven_Hansen_Shapiro_AER_2019_116213/R/154_freyaldenhoven_hansen_shapiro_replicate.R.

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.

- `AER/Freyaldenhoven_Hansen_Shapiro_AER_2019_116213/R/154_freyaldenhoven_hansen_shapiro_replicate.R` (171 lines)
- `AER/Freyaldenhoven_Hansen_Shapiro_AER_2019_116213/verdict.md` (38 lines)
- `AER/Freyaldenhoven_Hansen_Shapiro_AER_2019_116213/aeraej-154.md` (225 lines)