Staggered Synthetic Control Estimation and Inference R package stagsynth version 0.1.0 Implements the Staggered Synthetic Control (SSC) method for estimating treatment effects in panel data with staggered adoption, as proposed by Cao, Lu, and Wu (2020) <doi:10.48550/arXiv.1912.06320>. Constructs synthetic control weights via constrained quadratic programming, estimates heterogeneous treatment effects and event-time average treatment effects on the treated (ATT), and provides placebo-in-time confidence intervals and p-values. Software Depends: R (>= 3.5.0) Imports: quadprog Suggests: ggplot2, testthat (>= 3.0.0) Zhanchao Fu <fuzhanchao2001@gmail.com> Comprehensive R Archive Network (CRAN) Zhanchao Fu [aut, cre], Jianfei Cao [aut] GPL (>= 3) 2026-04-28 application/tgz https://CRAN.R-project.org/package=stagsynth doi:10.32614/CRAN.package.stagsynth