Multivariate Difference Between Two Groups R package multid version 1.0.2 Estimation of multivariate differences between two groups (e.g., multivariate sex differences) with regularized regression methods and predictive approach. See Ilmarinen et al. (2023) <doi:10.1177/08902070221088155>. Deconstructing difference score correlations (e.g., gender-equality paradox), see Ilmarinen & Lönnqvist (2024) <doi:10.1037/pspp0000508>. Includes also tools that help in understanding difference score reliability, conditional intra-class correlations, tail-dependency, and heterogeneity of variance estimates. Package development was supported by the Academy of Finland research grant 338891. Software Depends: R (>= 3.5) Imports: dplyr (>= 1.0.7), glmnet (>= 4.1.2), stats (>= 4.0.2), pROC (>= 1.18.0), lavaan (>= 0.6.9), emmeans (>= 1.6.3), lme4 (>= 1.1.27.1), quantreg (>= 5.88), lmerTest (>= 3.1.3), ggpubr (>= 0.6.0), ggplot2 (>= 3.4.4), rlang (>= 1.1.6) Suggests: knitr (>= 1.39), rmarkdown (>= 2.14), overlapping (>= 1.7), rio (>= 0.5.29) Ville-Juhani Ilmarinen <vj.ilmarinen@gmail.com> Comprehensive R Archive Network (CRAN) Ville-Juhani Ilmarinen [aut, cre] (ORCID: <https://orcid.org/0000-0001-9493-379X>) GPL-3 2025-09-23 application/tgz https://CRAN.R-project.org/package=multid doi:10.32614/CRAN.package.multid