The Iterated Score Regression-Based Estimation R package ISR version 2025.5.16 We use the ISR to handle with PCA-based missing data with high correlation, and the DISR to handle with distributed PCA-based missing data. The philosophy of the package is described in Guo G. (2024) <doi:10.1080/03610918.2022.2091779>. Software Depends: R (>= 3.5.0) Imports: MASS, stats Suggests: testthat (>= 3.0.0) Guangbao Guo <ggb11111111@163.com> Comprehensive R Archive Network (CRAN) Guangbao Guo [aut, cre] (ORCID: <https://orcid.org/0000-0002-4115-6218>), Haoyue Song [aut], Lixing Zhu [aut] MIT + file LICENSE (https://CRAN.R-project.org/package=ISR/LICENSE) 2025-05-16 application/tgz https://CRAN.R-project.org/package=ISR doi:10.32614/CRAN.package.ISR