Bivariate Within- and Between-Cluster Correlations R package wbCorr version 0.3.2 Separates supplied variables into within- and between-cluster components and calculates bivariate correlations for each level separately. For Pearson correlations, the centered-score decomposition corresponds to commonly used between- and within-cluster correlations reviewed by Tu et al. (2025) <doi:10.1002/sim.10326>. The package's descriptive Spearman option is distinct from the clustered rank parameters introduced in that paper. The package is also motivated by the distinction between within- and between-person variation described by Curran and Bauer (2011) <doi:10.1146/annurev.psych.093008.100356> and by Hamaker (2024) <doi:10.1080/00273171.2022.2155930>. The package is intended for longitudinal or otherwise clustered data where researchers need transparent correlation matrices before fitting more complex multilevel models. Software Depends: R (>= 3.5.0) Imports: methods, writexl Suggests: httr, knitr, psych, rmarkdown, spelling, testthat (>= 3.0.0) Pascal Küng <pascal.kueng@psychologie.uzh.ch> Comprehensive R Archive Network (CRAN) Pascal Küng [aut, cre, cph] (ORCID: <https://orcid.org/0000-0001-7346-9414>) MIT + file LICENSE (https://CRAN.R-project.org/package=wbCorr/LICENSE) 2026-07-23 application/tgz https://CRAN.R-project.org/package=wbCorr doi:10.32614/CRAN.package.wbCorr en-US