Analysing Prediction Stability of Non-Deterministic Prediction Models R package APS version 1.0.1 Provides methods to analyse the stability of non-deterministic prediction models. Prediction stability is quantified either as data-based prediction stability (phi) or as model-based prediction stability (psi). The package implements measures for categorical, ordinal, and metric predictions based on repeated model fitting and corresponding predictions. Methods are based on Lange et al. (2025) <doi:10.1186/s12859-025-06097-1>. Software Depends: R (>= 3.6.0) Imports: stats Suggests: ranger, covr, rmarkdown, spelling, testthat Thomas Martin Lange <thomas.lange@uni-goettingen.de> Comprehensive R Archive Network (CRAN) Thomas Martin Lange [cre, aut] (ORCID: <https://orcid.org/0000-0003-4351-7950>), Felix Heinrich [ctb] (ORCID: <https://orcid.org/0000-0002-6093-8522>) GPL (>= 2) 2026-04-16 application/tgz https://CRAN.R-project.org/package=APS doi:10.32614/CRAN.package.APS