Creates Group Sequential Trial Designs when Early Outcomes are Available R package gsearly version 1.1.1 Methods to construct and power group sequential clinical trial designs for outcomes at multiple times. Outcomes at earlier times provide information on the final (primary) outcome. A range of recruitment and correlation models are available as are methods to simulate data in order to explore design operating characteristics. For more details see Parsons (2024) <doi:10.1186/s12874-024-02174-w>. Software Depends: R (>= 4.1.2) Imports: graphics, grDevices, gsDesign (>= 3.2.1), methods, mvtnorm (>= 1.2-4), nlme (>= 3.1-160), stats, utils Nick Parsons <nick.parsons@warwick.ac.uk> Comprehensive R Archive Network (CRAN) Nick Parsons [aut, cre] (ORCID: <https://orcid.org/0000-0001-9975-888X>) GPL (>= 2) 2026-07-15 application/tgz https://CRAN.R-project.org/package=gsearly doi:10.32614/CRAN.package.gsearly