Abstract
Mobile research methods such as experience sampling, smartphone logging, and daily diary designs produce nested data, in which within-level fluctuations must be distinguished from between-level differences. Yet, there is no established convention for preparing and descriptively reporting such multilevel data. This paper introduces mlstats, an open-source R package that computes multilevel descriptive statistics — including intraclass correlation coefficients and within- and between-group correlations — in a single call, exports publication-ready tables, and decomposes variables for random effects within-between (REWB) modeling. Supporting both frequentist and Bayesian estimation, mlstats is freely available on CRAN with extensive online documentation at https://felixdidi.github.io/mlstats/.