Two-Stage Difference-in-Differences Following Gardner (2021) R package did2s version 1.2.1 CRAN Task View: CausalInference (https://CRAN.R-project.org/view=CausalInference) CRAN Task View: Econometrics (https://CRAN.R-project.org/view=Econometrics) Estimates Two-way Fixed Effects difference-in-differences/event-study models using the approach proposed by Gardner (2021) <doi:10.48550/arXiv.2207.05943>. To avoid the problems caused by OLS estimation of the Two-way Fixed Effects model, this function first estimates the fixed effects and covariates using untreated observations and then in a second stage, estimates the treatment effects. Software Depends: R (>= 3.5.0), fixest (>= 0.13.2) Imports: boot, broom, data.table, did, didimputation, dreamerr, ggplot2, HonestDiD, Matrix, rlang, staggered, stats Suggests: haven, knitr, rmarkdown, testthat (>= 3.0.0) Kyle Butts <buttskyle96@gmail.com> Comprehensive R Archive Network (CRAN) Kyle Butts [aut, cre] (ORCID: <https://orcid.org/0000-0002-9048-8059>), John Gardner [aut] (ORCID: <https://orcid.org/0000-0002-4028-6862>), Grant McDermott [ctb] (ORCID: <https://orcid.org/0000-0001-7883-8573>), Laurent Berge [ctb] MIT + file LICENSE (https://CRAN.R-project.org/package=did2s/LICENSE) 2026-03-05 application/tgz https://CRAN.R-project.org/package=did2s doi:10.32614/CRAN.package.did2s