GMM Estimation of Treatment Effects Under Staggered Adoption R package staggeredGMM version 0.1.0 Estimates cohort-by-time average treatment effects under staggered treatment adoption by the generalized method of moments. Three weighting schemes are provided, corresponding to a pooled stationary covariance, a cohort-specific stationary covariance, and an unrestricted within-cohort covariance. Optional adjustment for baseline covariates by outcome regression, and a serial-correlation robust over-identification test of parallel trends and no anticipation, are also supported. The methods are described in Arora and Bijani (2026) <doi:10.2139/ssrn.6558759>. Software Depends: R (>= 4.1.0) Imports: fixest, MASS, stats, utils Suggests: covr, data.table, knitr, rmarkdown, testthat (>= 3.1.5) Rishabh Bijani <rishabhbijani@gmail.com> Comprehensive R Archive Network (CRAN) Rishabh Bijani [aut, cre, cph] (ORCID: <https://orcid.org/0009-0003-9636-1774>), Parush Arora [aut, cph] (ORCID: <https://orcid.org/0009-0004-6571-3850>) MIT + file LICENSE (https://CRAN.R-project.org/package=staggeredGMM/LICENSE) 2026-09-15 application/tgz https://CRAN.R-project.org/package=staggeredGMM doi:10.32614/CRAN.package.staggeredGMM