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fetwfe: Fused Extended Two-Way Fixed Effects

Calculates the fused extended two-way fixed effects (FETWFE) estimator for unbiased and efficient estimation of difference-in-differences in panel data with staggered treatment adoption. This estimator eliminates bias inherent in conventional two-way fixed effects estimators, while also employing a novel bridge regression regularization approach to improve efficiency and yield valid standard errors. Also implements extended TWFE (etwfe) and bridge-penalized ETWFE (betwfe). Provides S3 classes for streamlined workflow and supports flexible tuning (ridge and rank-condition guarantees), automatic covariate centering/scaling, and detailed overall and cohort-specific effect estimates with valid standard errors. Includes simulation and formatting utilities, extensive diagnostic tools, vignettes, and examples. See Faletto (2025) (<doi:10.48550/arXiv.2312.05985>).

Version: 1.5.0
Depends: R (≥ 4.1.0)
Imports: expm, glmnet, grpreg, Matrix (≥ 1.6-0)
Suggests: bacondecomp, knitr, rmarkdown, dplyr, did
Published: 2025-07-02
DOI: 10.32614/CRAN.package.fetwfe
Author: Gregory Faletto ORCID iD [aut, cre]
Maintainer: Gregory Faletto <gfaletto at gmail.com>
BugReports: https://github.com/gregfaletto/fetwfePackage/issues
License: MIT + file LICENSE
URL: https://github.com/gregfaletto/fetwfePackage
NeedsCompilation: no
Citation: fetwfe citation info
Materials: README NEWS
CRAN checks: fetwfe results

Documentation:

Reference manual: fetwfe.pdf
Vignettes: FETWFE Simulation Vignette (source, R code)
fetwfe: A Package for Fused Extended Two-Way Fixed Effects (source, R code)

Downloads:

Package source: fetwfe_1.5.0.tar.gz
Windows binaries: r-devel: fetwfe_1.5.0.zip, r-release: fetwfe_1.5.0.zip, r-oldrel: fetwfe_1.5.0.zip
macOS binaries: r-release (arm64): fetwfe_1.5.0.tgz, r-oldrel (arm64): fetwfe_1.5.0.tgz, r-release (x86_64): fetwfe_1.5.0.tgz, r-oldrel (x86_64): fetwfe_1.5.0.tgz
Old sources: fetwfe archive

Linking:

Please use the canonical form https://CRAN.R-project.org/package=fetwfe to link to this page.

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.
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